Water Changes With Normal Parameters

[Bignose]

fish in but lightly stocked and heavily planted

yes there is reason behind it, as the others said above you can get build up of chemicals which needs reduction and water changes can trigger spawning in same fish.

This isn't a limitation. Diana Walstad has shown in her book Ecology of the Planted Aquarium that with good healthy plants you can stock as heavily as a filtered tank. She's had a 55 gal tank with over 60 guppies (and lots of plants, of course) in it for many years now without a problem. This "heavily planted and lightly stocked" is a hangover from the early days of fishkeeping. Today, we know how to keep the plants a lot more healthy, and if you can keep the plants healthy, then you can have just as many fish as the filtered tanks.

SP, you probably will want to read that book. She has very close to a closed system. She only does water changes every few months. She also goes into more detail on the various cycles that occur in the tank. Probably worth finding a copy.

 

[steelhealr]

As mentioned above, each water change usually comes after a period of evaporation. Lets say you have tap water that is 10X of some chemical that you don't measure normally and let's assume that you allow 50% to evaporate (which you normally wouldn't do). You now have 20X. If you simply top off the water with your tap...you've added more 10X concentration water, leaving you with now (uh...Bignose..keep me honest here..) 15X. Each time the concentration would increase. By doing water changes, you remove any buildup of unwanted minerals or chemicals (eg, copper or heavy metals, depending on your pipes or water system).

That is one reason. SH

 

[Miss Wiggle]

fish in but lightly stocked and heavily planted

yes there is reason behind it, as the others said above you can get build up of chemicals which needs reduction and water changes can trigger spawning in same fish.

This isn't a limitation. Diana Walstad has shown in her book Ecology of the Planted Aquarium that with good healthy plants you can stock as heavily as a filtered tank. She's had a 55 gal tank with over 60 guppies (and lots of plants, of course) in it for many years now without a problem. This "heavily planted and lightly stocked" is a hangover from the early days of fishkeeping. Today, we know how to keep the plants a lot more healthy, and if you can keep the plants healthy, then you can have just as many fish as the filtered tanks.

SP, you probably will want to read that book. She has very close to a closed system. She only does water changes every few months. She also goes into more detail on the various cycles that occur in the tank. Probably worth finding a copy.

yeah we've got that book, must confess it's a bit hard going for me but Ian's read it.

he just likes lightly stocked tanks though

 

[Spider Pig]

Interesting article (The Chemical Composition of Settleable Solid Fish Waste (Manure)from Commercial Rainbow Trout Farms in Ontario, Canada STEPHEN J. NAYLOR, RICHARD D. MOCCIA,* AND GORDON M. DURANT) but difficult to extrapolate to home aquarium. Being an intensive fish farm, it is likely that they would have a different diet to aquarium fish, and each species would metabolise nutrients differently. Their food intake contains significant amounts of the trace and heavy metals and it would be interesting to know if aquarium feeds are the same. The values given are for dry waste collected over 24 hours so their is no indication of the concentration of the chemicals in the water. Also the accuracy of the data has to be questioned given the wide error margins- e.g. Hg +/- 0.05, Fe 1942 +/- 1123. Just eyeballing the results it looks like there is fair variation between the studies which is accepted by the authors, making it harder to apply to an aquarium.

The interesting conclusion is that this waste is suitable for fertiliser. Assuming that nutritional needs for aquatic plants are the same as for land plants, one can extrapolate that these nutrients can be used by the plants and so locked away from the fish. I'm sure I heard that Duck weed is particularly effective at stripping heavy metals from water which is why it is used in sewage plants. Another way to remove them would be a carbon filter. Both the effect of the plants using the nutrients and the carbon filter would also have the effect of dropping the TDS by utilising these free ions.

Of course this study only looks at solid wastes so there is no mention of dissolved toxins and so far the identity of these seems as elusive as ever.

It is interesting that Diana Walstad only changes her water every few months, Do you know what prompts her to do that? Saw the book in amazon- looks interesting reading but any thing stating to be a scientific treatise sounds like heavy going.

Just to clarify my rebuttable hypothesis is this: it is possible to maintain an aquarium with flora and fauna without removing any water. Addition of water, distilled or otherwise is permitted as are different filtration methods with various media. Removal of flora is permitted.

The concentration of chemicals by evaporation can be avoided using distilled water, which just replaces the evaporated water alone. I'm not convinced that the chemicals mentioned in the study above cannot be removed by plants or filtration.

The other interesting question is that of water conditioners such as tetra easy balance claiming that water changes are required only once every 6 months. It would seem quite a stretch if this could do away with all nasties. here's their pitch:

Q: How can EasyBalance possibly replace regular water changes?

A: At first it might seem impossible that a single product could replace the effects of regular water changes. However, when you break the effects of water changes down, it is soon apparent that they do no more than cause a set of changes to the chemistry of the aquarium water.
These changes are:
a) Replenishment of the mineral content of the water, which is important for maintaining fish health, filter function, and a stable pH.
B) Replenishment of some of the vitamins and other trace elements, which are essential for fish and plants.
c) Dilution of nutrients, such as nitrate and phosphate, which encourage algae growth. In may cases though, this effect is minimal, as tap water can contain high nutrient levels as well.

Have to take it with a pinch of salt, but no mention of unmentionable nasties.

 

[Bignose]

SP, if you could read that article I cited, you can read Walstad's book. It more science than most people are used to (which, quite frankly is none), but if you remember anything from high school chemistry, you should be able to get through it pretty easily. At least get the larger points. And, if you have any questions, you can always ask here. I got through the book pretty easily, but I am used to reading things like that. I seem to have misplaced my copy of the book (I moved a while back and haven't seen it since I moved, so it might be buried somewhere right now or gone, I don't know), so you might have to write out some large parts of it, but I don't think that you'll have too much problems with it at all.

It is going to be awfully tough to find any studies about aquarium fish -- there really just isn't much money in it. Aquarium fish usually get studied when they are first discovered, then the common fish like zebra danios or goldfish are used in a lot of toxicity studies, but that's about it. The food fish farms are where the research is done -- much, much more money in it compared to aquarium fish. Their diets aren't going to be too different -- probably a little more protein to encourage growth, but a good quality aquarium fish food is going to be similar. I can't cite a direct source for this, except to tell you that I asked a worker at a fish hatchery and she said they feed Omega One flakes to the fry, so they are getting the same stuff we can get.

There are a few articles in Google scholar if you search for "composition fish urine" Something like this one <a href="http/www.springerlink.com/content/p57015h41q35jhw2/" target="_blank">http/www.springerlink.com/content/p57015h41q35jhw2/</a> might be really good. I don't have access to download these, so I can't look at them specifically. If you can, let us know what they say!

Oh, finally, I wanted to add about the EasyBalance stuff. This is an old thread on here (I'll try to look for it later), where a member kept two tanks. Two groups of guppys in each tank, both groups taken from the same batch of fry. One tank he did the weekly 25% water changes, the other he followed the instructions on the EasyBalance bottle. For almost a year he kept these tanks, and did everything else equally (i.e. same light, same temperature, same decorations, etc). The guppies in the water changed tank were their usual frisky fry-making selves. Many pregnancies and batched of healthy fry. In the EasyBalance tank, the guppies did not breed. At all. If common guppies aren't breeding, something is wrong. That pretty much closed the book about EasyBalance for me.

 

[Spider Pig]

Found a couple of studies suggesting that zero discharge systems aren't a "fools errand" as the commercial cost of discharge fees can be quite high.

Nadav Shnel a,b, Yoram Barak a, Tamir Ezer b, Zaev Dafni b,Jaap van Rijn a,*Design and performance of a zero-discharge tilapia recirculating system Aquacultural Engineering 26 (2002) 191–203
This study looked at an intensive tilapia farm where the only water removed was during weighing and transport of fish to market. Water was replaced for evaporation losses. The conclusion was that this was viable for a long term system- this study was carried out over 331 days. Growth rates were comparable to other fish farms
Their conclusion
"The technical feasibility of zero-discharge recirculating systems incorporating denitrifiers fed with endogenous produced carbon has been studied by a number of investigators (Kaiser and Schmitz, 1988; van Rijn and Rivera, 1990; Schmitz- Schlang and Moskwa, 1992; Arbiv and van Rijn, 1994; Schuster and Steltz, 1998).
The latter studies were conducted during relatively short-term growth trials. In this study, we demonstrate that also on a long-term basis, fish can be successfully
cultured without adverse effects associated with long-term use of re-use water. Although the system in this specific reported season included a fluidized bed reactor
for nitrate removal, results of this study indicate that anoxic treatment might be accomplished successfully by eliminating this latter treatment step. Presently, the
same tilapia culture system is operated successfully for the second successive year using a sedimentation/digestion basin as the only anoxic treatment stage."

Another study looked at a closed marine set up for 17 months.
Amir Neori a,⁎, Michael D. Krom b, Jaap van Rijn c. Biogeochemical processes in intensive zero-effluent marine fish culture with recirculating aerobic and anaerobic biofilters
Journal of Experimental Marine Biology and Ecology 349 (2007) 235–247
This looked at the processes in the system and how they affect the marine environment. They concluded that the main factors were nitrates, phosphates and hydrogen sulphide which were all degraded within the system.

No studies I have looked at mention any of these other fish by products alluded to above. It doesn't prove that they don't exist, just that they are not significant. They would also have a greater effect in an intensive fish farm than a home aquarium.

As stated above it is hard to extrapolate findings from an intensive fish farm to a home aquarium. I can't say I was familiar with a lot of the filter types employed, but I wouldn't be surprised if it can be replicated in a home aquarium.

For those concerned by heavy metals duckweed (Lemna spp.) seems quite effective: Shanti S. Sharma *, J.P. Gaur Potential of Lemna polyrrhiza for removal of heavy metals Ecological Engineering 4 (1995) 37-43. This only looked at Zn, Pb, and Ni but other articles are available looking at other metals.

On the Easy balance front it would appear to be detrimental, of course more information on the study is required to draw valid conclusions. For example easybalance may affect breeding but not necessarily fish health, the two aren't directly related. It is hard to conclude that water quality is the culprit without knowing that there are no toxins in Easybalance it self. I think I saw a post on another forum stating that it has vitamins, minerals, salt and formaldehyde- can't say for certain, but preservation fluid is sure to stunt someone's libido.

At present, from the facts presented on this thread, I am still not convinced that water quality cannot be maintained without water exchange.

 

[Bignose]

OK, but who's going to buy/build a complicated system with a nitrate fluidized bed and the whole recirculating system for a home aquarium? Is it really necessary? Is it really that big of an issue to do a water change once in a while?

I don't think that I ever said it was impossible. I just don't see how it could be beneficial. I guess I am more focused on the practical side of the issue in that, while I never said it was impossible, it would be prohibitively expensive and just not worth it. At least not for home systems -- I can understand the fish farming interests. But, yes, it looks like there is evidence that it is possible.

I also suspect that one year may not be enough to find the non-closed parts of the system. I wouldn't be surprised if something turned up 2, 3, 5 years later -- some sort of deficiency or something that wouldn't be noticed in less than a year.

You never did address the issue about all the household chemicals that get into the tank -- carpet fumes, cooking oils, fumes from cleaning products, etc. Duckweed and a nitrate reactor aren't going to take care of those things -- there are still compelling reasons to do water changes.

I've got at least one final reason I think doing water changes is still good. It gives me a chance to interact with the tank and the fish. I like getting in there and cleaning some algae off the glass, and doing a little work. It's the closest you can get to petting them (though a few of the mollies I have like to be petted none of the other fish do). Besides, it really isn't all that hard or expensive, so again I don't really see the advantage.

 

[Spider Pig]

The point is not that it is possible to have a closed system but that if there are any other toxins present as byproducts of fish metabolism, then these are not significant to water quality, that is their removal by water changes has no significant effect on fish health. As such the significant factors are those highlighted in the articles. If those are stable then there is no factual reason for a water change. The practical aspect of this is not that people need extensive filtration systems, but if they have water parameters within acceptable levels then water changes are not required. Surely this would have a great impact for aquarists especially those with large or many tanks? Doing 20% water changes on 500L tanks every two weeks must hit the wallet after some time when factoring in conditioner costs. Also there is the environmental impact to consider where some places are facing restrictions on water usage.

As regards volatile atmospheric pollution, again much of this could be removed by activated carbon, such as used in cooker hood filters. Even if not- how significant is it, is there evidence of it affecting the health of fish in the concentrations reasonably encountered.

As regards petting the fish, that might be desirable for a pet owner but not necessarily for the pet. Introduction of any foreign material into an ecosystem is potentially hazardous. Sweat, oils and commensal skin bacteria entering the aquarium could have as deleterious effect as atmospheric pollutants. I labour the point not to condemn petting, I love to hand feed my fish, just to point out that it isn't necessary, only desirable to the aquarist.

As such still unconvinced for need to do water changes

 

[geo7x]

The point is not that it is possible to have a closed system but that if there are any other toxins present as byproducts of fish metabolism, then these are not significant to water quality, that is their removal by water changes has no significant effect on fish health. As such the significant factors are those highlighted in the articles. If those are stable then there is no factual reason for a water change. The practical aspect of this is not that people need extensive filtration systems, but if they have water parameters within acceptable levels then water changes are not required. Surely this would have a great impact for aquarists especially those with large or many tanks? Doing 20% water changes on 500L tanks every two weeks must hit the wallet after some time when factoring in conditioner costs. Also there is the environmental impact to consider where some places are facing restrictions on water usage.

Ok, I find some of the technical language in the articles you have provided hard to understand, but I will try my best.

You say "If those are stable then there is no factual reason for a water change". What are the "those" you speak of? Ammonia, nitrate, nitrite and hardness are the obvious ones, but I would expect you would need a phenomenal amount of test kits (Many of which don't exist) to test every single harmful substance that could possibly build up in the tank as a result of doing no water changes. With such a risky procedure of not doing water changes tests would have to be done regularly, and since we have moved on to "cost effectiveness", baring in mind I only test my tank once every blue moon and do weekly water changes, I'm sure even with no water changes but regular testing my fish costs would be higher. Aquarium dechlorinator is expensive, but many people with many or large tanks use pond dechlorinator which costs a fraction of the price. Additionally, on the point you made on people with large tanks, most of them would need extensive filtration systems. With large tanks come large fish which mean a lot of waste, so I doubt they would be able to be kept stable in the delicately balanced setups that you are describing.

As regards volatile atmospheric pollution, again much of this could be removed by activated carbon, such as used in cooker hood filters. Even if not- how significant is it, is there evidence of it affecting the health of fish in the concentrations reasonably encountered.

Perhaps a lot of harmful substances could be removed by activated carbon, but with this I must again refer back to costs. I personally do not use any carbon in my filters. Carbon is very expensive. I'm sure it would cost just as much (or more) to keep renewing carbon in my filter than it would do simply do water changes to get rid of toxins the cheaper way. Additionally I believe (though don't quote me on this) that after a certain amount of time activated carbon stops removing toxins, how could you judge when this point has come until it turns fatal? For most with carbon this is not an issue because they do water changes as well.

Futhermore I doubt this system with a nitrate fluidized bed would be cheap

 

[Spider Pig]

Main waste products identified in Amir Neori a,⁎, Michael D. Krom b, Jaap van Rijn c. Biogeochemical processes in intensive zero-effluent marine fish culture with recirculating aerobic and anaerobic biofilters Journal of Experimental Marine Biology and Ecology 349 (2007) 235–247 were nitrogen wastes, phosphates and hydrogen sulphide which were all degraded within the system. Other waste products were not deemed significant- that was my interpretation after skim reading the article- would be grateful for clarification or alternative interpretation. These set ups are commercial fish farms so big fish with big waste- Bignose referred to an article directly relating to that.

The aim of these examples was not that you need a fluidised bed reactor (whatever that is) to remove nitrates, but if you have a nitrate removal system- like plants, and your measured nitrates is 0 then there is no other reason to do a water change. The cost effectiveness issue is a side point to the original question and I probably should have avoided the issue to keep the issue on track.

Carbon is a means of removing these postulated toxic doses of chemicals- however no evidence presented of level of heavy metals/ atmospheric pollutants and so how often carbon need to be changed.

Still unconvinced

 

[Bignose]

I don't know if there is anything else that will convince you, then. I can only go back and say some of the same things over. You can sustain life in a completely recirculating system, but I think that a quality of life component is important too. Why are the sailors who finish a mission on a submarine so happy to breath fresh air? Or the astronauts? They get tried of the recycled stale air. Fresh air is always very welcome. And I think that it is exactly the same for fish. Nothing but anecdote here, but again, my fish always seem so much more frisky and happy after a water change. I wish I had the time, because I'd like to do a water change every day if I could. Their colors usually seem brighter and they are more active for many, many hours after the water change (not just from the disturbance of the change itself).

There isn't going to be any research out there about the effects of fumes getting into the water. There is no money to do that kind of research, so no scientist is going to do it. I don't know what the levels are going to be, I just know that I don't like breathing in the fumes, and that I do not want that stuff in the tank. And that I know that doing water changes siphons them out and dilutes them, so their concentration doesn't get very high.

So, like I said, nothing but anecdote. But, I think that it is a significant improvement in the fish's lives to have fresh water regularly.

If I may ask here, what is your overall goal here? Had you just asked in the beginning, "is it possible to create a life support system that in theory could run indefinitely?" then I would have easily answered yes. But, you started out with asking if home aquariums need water changes, and while the research shows that you can create a life support system, I still think that home aquariums need water changes. If only because of the anecdote I listed above. So, where are trying to go with this question that has seemed to change from the beginning of the thread to now? Will fish live without waterchanges ... yes, given the appropriate maintenance equipment. But, is that really what is best for them? I'd say no,

 

[geo7x]

I agree with Bignose.

This topic seems to have changed its course somewhat. Originally you were simply enquiring on whether you still have to carry out water changes on your (seemingly) average home aquarium that apparently has perfect parameters. The answer to this is no.

However further throughout the topic you seem to have swayed on to a much more technical side of things. The theory behind this is, undoubtedly, correct. However I personally think there is much more behind keeping fish in a glass box than scientific equations. Rivers in the wild don't go by these, they are constantly flowing, replenishing water and minerals and providing constant fluctuations in temperature.

It doesn't take a biologist to recognise that fish obviously thrive off and 'enjoy' exchange of water.

In such an extraordinary set up that you are describing (to be honest I would rather do water changes once a week than research all that lot and set up such a monstrosity of an aquarium) then the fish would stay alive yes, but there there is something about water changes that fish thrive off.

Additionally, I know you tried to dismiss the cost effective argument, but to be fair it is a perfectly valid argument against not carrying out water changes, meaning that not only is not doing water changes causing fish not to thrive (they would live but wouldn't thrive) but additionally it is not practical due to so many complications and such a large scope for error, it would probably cost a lot of money, and would be risky considering the lack of research available on many aspects of keeping such a set up (e.g. carbon lifespan and airbourne toxins.)

 

[Spider Pig]

I agree that the original question has morphed somewhat but that is the nature of scientific enquiry.

Start with a broad question- do I need to do water changes if my water parameters are normal?

Then analyse the components: ones brought up here are toxic waste products, heavy metals, aerial volatile toxins and Cost, . The majority of my discussion on this thread has been aimed at the first three. If analysed all together, one component may be discounted because of the influence of another without analysing whether or not it is a significant factor or not. So in this case all the first three factors may be subordinated to cost implications.

What would convince me is the documented presence of significant other toxins that are known to be harmful to fish. No convincing evidence for the existence of these has been put forward- by convincing I class any thing up from expert opinion e.g. a published paper, book ref etc. Anecdotes are informative, and sometimes all one can go on in the absence of scientific proof, but the user must retain the necessary scepticism to question these. So if expert opinion is all that is available and any of the posters are scientific experts in the field then that is what we would have to go on.

Bignose- I notice that you are quite vociferous about the need for scientific proof to back up statements in other threads, but would you be convinced by someone who says they have drunk RO water for their whole life without any problems? I respect your opinion, but the reason I posted this thread on the scientific section was to get a scientific answer, as seemed to be the aim looking at the pinned topics.

My overall goal is knowledge. It irritates me when things are done mechanistically just because they have always been done so. There has been a shift in medicine over the last couple of decades to questioning the factual basis of common practices to see what really works. That's why doctors are sceptical of people who claim to have been healed by homeopathy even though that has been done for hundreds of years. Even established medical practices have been shown wanting and disposed. The same sceptical attitude can be applied throughout life. I don't demean people who aren't sceptical, it's just not a choice I would make.

Knowledge applied- why do I need to do a monthly water change if water parameters are 0, plants are stripping nitrates, and there is no subjective benefit to the fish that I can ascertain. Can I extend that time safely with accurate monitoring of water parameters, which would be done with or without water changes. A document on the JBL website suggests that often rigorously clean tanks do not have the same biofilm and so capacity to absorb changes in water parameters as well as tanks with a good layer of mulm and anaerobic areas where denitifying bacteria release free nitrogen rather than nitrates. Would regular, preferably daily as Bignose would suggest, water changes contribute or detract to this? I would be reluctant not to do a water change at all for the intuitive benefit of it as referred to throughout the post, and taking account of the lack of quality scientific data on the subject.

Cost implications would weigh heavily against this if the massive filters suggested in the studies were required, but I'm not sure that they are- remember those were commercial fish farms and as i stress yet again was only an illustration regarding significant waste materials. Bignose- you mentioned that Diana Walstad had aquaria without water changes for many months- did she need a fluidised bed nitrate filter? I asked this same question on another forum and one member said that when he had his first tank 25 years ago, that was kept for 3 years without water changes, with healthy breeding cories. Again anecdote.

My point in all of this is to find the scientific basis behind common wisdom. If this scientific forum is not the place to do that, then so be it.

 

[geo7x]

My point in all of this is to find the scientific basis behind common wisdom. If this scientific forum is not the place to do that, then so be it.

This is the place to do that but you just won't believe anything unless there are scientific papers to back it up. As Bignose has already been saying there simply aren't any papers around about the issues you are raising, so unless we can find someone on here that is willing to write such papers for us then this topic is not going to progress any further. What's the point in creating a scientific forum (the word forum undoubtedly implies conversation) if all we are allowed to do is post links and quotes to scientific papers? Sharing knowledge is just as important.

So expert opinion (i.e. thousands of members on a forum passing on their knowledge) is all we have to go on, and in my opinion it is only common sense to assume that there are various toxins in the atmosphere that are harmful to fish if they are exposed to them. Humans die from solvent misuse of household products, so what do you expect it does to fish even in small quantities?

But overall it has already been repeated that yes you can make up a life support system if you have a lot of time and more money than sense, but please forgive me and Bignose for assuming that you weren't going to change subject so unexpectedly from the simple average home aquarium (On which note I would like to know how densely planted your aquarium is to be able to keep such constant parameters in a relatively new tank. Either that or check your test kits) to some great life support system which requires a countless amount of testing (£££) and various methods of reducing toxins (£££) which quite simply is not practical. I know about these fish farms, but to be honest you were originally enquiring about one home aquarium.

 

[andywg]

One thing I am interested in is the relative biomass density between the fish farms in the studies and our tanks. While the farms will have a large biomass of fish, they will also have a very large volume of water for those fish to be in.

I would not be surprised to see that intensive fish farms do not stock with a biomass:water ratio as heavy as our tanks are (though I may well be wrong here).