Water Changes With Normal Parameters

[Spider Pig]

I think the words "head" and "brick wall" can be used in an answer to your post geo7x, but I will try to answer none the less.

If this scientific forum doesn't rely on scientific evidence then what makes it different to any of the other forums. I think I misunderstood steelhealr's pinned post regarding guidelines for posting to this section of the forum, notably:

"All our members are welcome to come here, whether you are a marine biologist, well-published scientist or just new to the hobby. This forum will NOT be like the other TFF sections in that this will not be a place for the expression of opinion or presentation of experience based on owning a single fish."

And no, 1000 people saying they believe the same thing, no matter how strongly, is not expert opinion- I hope Bignose will back me on this one. 2 millenia ago over a thousand people thought very strongly (killing others who didn't) that the sun was pulled across the sky in a fiery chariot every day- unfortunately that isn't expert opinion and it isn't scientific fact (I hope I don't need to quote a paper there.) A well conducted survey of a 1000 people may provide evidence of a consensus of opinion, but it should be interpreted at that level.

"Please present your topics and posts to a level comparable to a peer-reviewed scientific journal article"

Peer reviewed journals don't take kindly to people saying do this because I do it and know lots of other people who do it (I've tried in jest, doesn't work), usually they want some reference to scientific literature . Bignose presented journal articles and I debated them and pointed out the flaws with them. Anyone is free to disagree and I would welcome it. I am not an expert by any stretch of the imagination and what I understood from them may be widely off the mark.

"Alternative Concepts are welcome to be presented here. If you plan to present a topic that may be controversial, eg. whether fish feel pain or methods of euthanizing fish, be prepared to backup your comments. Claims/ideas/theories have to be backed up by some semblance of fact. Evidence has to be cited and direct questions need to be answered in a timely manner or the claims dropped. Be prepared to have your arguments attacked and vigorously."

That must apply to counter arguments to the concept, you can't just expect a proposer to roll over and say "sure, forget about all that evidence I put forward, I'm sure you're right." Again very unscientific.

To provide what you must consider a definitive counter to your opinion, I've seen anecdotal evidence and opinion that water changes aren't needed- there argument concluded.

I have already addressed the question of common sense and opinion in my previous post and the reason for changing the focus of the question (I could start another thread if you want)- I can't help feeling this was somewhat in vain.

Again, if my arguments and reasoning within this thread are misplaced or out of line with what is expected then I would be grateful for intervention or redirection by a moderator. Alternatively we could discuss whether to use crystal therapy instead of filtration

 

[Spider Pig]

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).

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
From abstract "Total tilapia biomass production over the grow-out period was 81.1 kg m−3 with maximum stocking densities of 61.8 kg m−3."

Not sure how that compares to home aquarium. I would have thought that they would stock higher to improve productivity and commercial viability. Also you would probably over feed them so they reach market size quicker, which would imply greater metabolism of food and so production of waste over a normal aquarium- purely hypothesis on my part.

 

[Bignose]

I'd like the science on the stuff in the air, too. But, like I said, no one is going to research this for us. Unless you are going to grant a large amount of money to some ichthyology department out there, or unless you are going to do the tests yourself, we have to go on opinion and instinct. Both of these can be wrong, but without further information, it is the best we can do. And, in my experience, if there is something in the air, it ends up in the water, too. This can be found in nature -- air pollution ends up in the water. So, based on that, the air pollution in our homes ends up in the water, too. At what levels? I don't know. But, these are things that I don't particularly care to breathe in, and again, similarly, I don't think the fish want to live in. Finally, it is known that long-term low-level exposure to toxins can be just as bad as acute high-level exposures. Sometimes worse, so my instinct says that even though the levels will be low, they doesn't necessarily mean no effect.

Walstad doesn't need a nitrate reactor because she heavily plants her tanks. The plants take up ammonia, and since there isn;t any ammonia not taken up by the plants, there is no bacterial colony and hence no nitrate generates. (Plants don't "strip nitrates" and in fact, most aquatic plants convert the nitrate back to ammonia before they put it to use. Please don't take this personally, but you do need to be very careful with your terminology and facts, e.g. that fact that the vast majority of aquatic plants prefer ammonia as their nitrogen source.) She basically re-started the "El Natural " planted tank movement. For a long time, people thought that the only way to have really lush plants is with CO2 injection, super bright lights, special fluorite substrate, and a strict schedule of fertilizer dosing. Walstad took her inspiration from nature, and uses potting soil substrte, no CO2 injection, puts the tanks so they receive significant amounts of sunlight, and the fish droppings are the fertilizer. This info is all in her book, please check it out.

I don't know what else to say, SP. I really feel like you put up a moving target and that made it significantly harder to hit. I still strongly feel that regular water changes for its refreshing effects are needed in home aquaria. I think that that is by far the best thing for the fish. That is the best to give them a long, happy, healthy life. As geo said, my particular goal isn't just to allow the fish to live, but I want them to thrive. And I think that the best way to do that is with regular water changes. I started from the beginning assuming that that was the goal for all of us, and that's why the beginning of the thread was so heavily leaned toward water changes; like I said above, had the first question been "can I create a sustainable life-support system where I don't need outside water?" then this thread would have taken a different tact.

The biggest thing is that I keep a tank to try to replicate a little slice of nature in my house. Nature doesn't keep any body of water stagnant or recycled. Streams constantly refresh themselves, and rain refresh larger bodies of water like ponds and lakes. This is a large reason, in my opinion, that water changes will always be excellent advice. It recreates the situation that constantly occurs in nature. Technology can prevent a lot of the need for the natural process, but that never ever means that the natural process was wrong or unneeded in the first place.

While common knowledge can be wrong, there is an awful lot of common knowledge that is right, too. There is a reason it became common knowledge in the first place. If it didn't work too well in the first place, it wouldn't have become common. Situations do change, and science does invite questions about it. But, changes aren't just made on a whim, either. I don't know how much this applies to the question at hand. Are you looking for someone's blessing to not do water changes on your tank anymore? You've found the evidence you think is most compelling, you make up your own mind. Again, I just don't know what else you want here?

 

[geo7x]

Sorry for my comparison involving expert opinion and the large quantity of people (which is really besides the point), but I only said that is available to us, I never said it was correct to believe it all. I would like a scientific paper of toxins as much as you but as of yet opinion and experience is all we have to go on. I know what it says in the pinned topic but that isn't going to magic a paper out of thin air. Additionally I would like to point out "This forum will NOT be like the other TFF sections in that this will not be a place for the expression of opinion or presentation of experience based on owning a single fish." Which, from what I can see, means that expression of opinion is only classed as not acceptable without experience. Bignose has pointed out his own experience and so have I, it is acceptable in my eyes and seems to be by the mods as well.

I do apologise for making you waste your time to give me quotes on what is and what isn't scientific, as I was merely using such comparisons to try and explain to you that there won't be any evidence or papers on the levels of toxins. I never said we should accept the opinions of thousands of people, it is only what we have to go by.

Additionally, like Bignose, although I mentioned the deadly "commonsense" word I backed it up with a perfectly reasonable explanation. If humans are given multiple health warnings on the back of aerosols, including the warning of death if they are misused, then I personally would not want such products being in my tanks.

I would not go down to referring the heads and brick walls, however you don't seem to understand that I am not denying that such a tank could be set up.

I think the question really is whether such a tank can be set up to be more efficient than simple water changes on a home aquarium, the answer is no as it is impractical.

The topic has been changed and perhaps therefore as a mere 15 year old it is no longer within my capabilities to discuss this topic, however I was originally replying to something about your home aquarium, so in order to win the argument the topic has moved on to huge scale industrial systems which, of course, would prove our original theories wrong but it is a totally seperate argument and has undoubtedly reached far beyond the realms of your typical home aquarium that we were discussing before.

I personally think that this argument has become unfair as surely if this a truely scientific debate you would have relfected that in your original question, but as Bignose said above, you are providing a constantly moving target and I'm glad that I'm not the only one that thinks that.

I agree with Bignose on how I do not understand what your overall goal is here, the original enquiry was referring to how it would affect your average home aquarium. Unfortunately my only conclusion is that you are constantly shifting the aims of the argument in order to be able to claim that you are right.

 

[Spider Pig]

Right, this has gone way off.

Regards opinions stated- accepted. No denying value of common sense, or the culminated opinions of generations. However I also hope you accept that it can be incorrect and needs to be challenged, even if it may be heresy (seems like it in this case). I couldn't find studies on toxicology but that does not mean it is not out there- if you don't look you don't find. I ACCEPT YOUR OPINIONS Bignose and geo7x, but balance them against other opinions- can't be fairer than that can I. If this is a scientific forum then it's not about winners and losers- what do you win- there is no prize, no pat on the back, no one cares who wins. Did I ever claim that I was right? I only challenged what was put forward- it didn't mean that challenge was definitive- great if you thought so, but didn't seem like it to me. If your opinion is valid then it doesn't matter if you're 15 or 115 if it has the same base. Age is irrelevant to science. Any question can be scientific if viewed as such- maybe it would have been clearer if I had asked "is regular H2O renewal required for maintenance of a domestic aquatic ecosystem if internal monitored environmental parameters are normal"- sounds like jibberish to me but hey...I did put forward a rebuttable hypothesis later, I hoped that would clear things up but maybe it was missed...

Regarding moving targets- I did explain a couple of posts back, would you prefer if I started another post? Thank you for your conclusions regarding the average home aquarium- other posts are aimed at examining this question further, and are NOT constrained to the home aquarium, but may be RELEVANT to it. Although I would welcome your further opinions in this area, please do not feel encumbered to provide them.

Moving on.....

Bignose, thanks for that, I didn't know how plants prefer to use nitrogen. I guess that's a good argument not to plant your tank before it is matured. I was never told that and planted straight away, although lightly- must have been sufficient excess to grow the bacteria. This comes back to the question about the significance of nitrogen compounds. I didn't think you need a nitrate reactor but the question is how heavily planted do you need to have the tank to cope with the waste from the fish. I guess if you have some thing fast growing like duckweed then this would use nitrogen compounds quite quickly and be able to be stripped out quickly. Although I would like to have a look at Walstad's book, unfortunately it's a way down on my wish list (things backing up for some time) might try to get a copy from the library. Do you remember how often she advocated water exchanges?

One reason for a benefit of delaying water changes is build up of biofilm- the idea of a mature tank. If you did change 10% water every day what effect do you think that would have on the "maturation" of the tank, could it inhibit the layers of biofilm that bombproof a tank?

But I guess the counter to that is that if you change 10% water each day then you wouldn't be concerned with the build up of metabolites as they would be washed out any way.

I guess one thing I would like to strive towards is balance- can you balance your tank in such a way that the fish thrive with the minimal intervention- a fools errand it may be, but if you don't ask... I guess what I want to know is how the system works in nature- if we understand that then we can care for our fish better. Merely replicating what happens in nature does not necessarily aid understanding. Maybe abstract and irrational, but hey, what are opinions for?

 

[geo7x]

OK, SP, I'm going to make a fresh start now and assume from now one that we are discussing the possibilities, however obscure

On the subject of biofilm, from searching on the internet I found an interesting article about it.

"Comparison of Bacterial Presence in Biofilms on Different Materials Commonly Found in Recirculating Aquaculture Systems"
Robin K. King, George J. Flick, Stephen A. Smith, Merle D. Pierson, Gregory D. Boardman, Charles W. Coale

This was based on the theory that was that in recirculating aquaculture systems (such as fish farms) "Pathogenic microorganisms may be incorporated into biofilms found in aquaculture systems, causing recurring exposure to disease agents"

"The presence of E. coli, modified to express a green fluorescent protein (GFP E. coli) was used to evaluate bacterial incorporation into biofilms in recirculating aquaculture systems. Disks of Buna-N rubber, polyvinyl chloride (PVC), chlorinated PVC, glass, fiberglass, and stainless steel disks, were placed in aquariums stocked with Nile tilapia, Oreochromis niloticus. Tanks were inoculated with a known amount of GFP E. coli and samples taken on days 1, 3, 7, and 15 post-inoculation."

It was found that by day three the number of organisms had initially decreased, however from there on the number remained consistent.

"This study demonstrated that bacteria can become incorporated into a biofilm with the potential for pathogen colonization of biofilms in aquaculture systems."

Surely, therefore, it is also necessary to carry out regular water changes in order to control pathogen conolisation of the biofilm, which would be harmful to fish.

 

[Spider Pig]

Interesting article- I couldn't access the article itself but only saw the abstract, so you might be able to help out with more information. From what I understand it was looking at the biofilm on certain materials, similar to what might be found in our tanks. Certainly if a pathogen was introduced then it suggests that these can be a reservoir for re-infection. Water changes may not reduce the pathogen colonisation however as the study seems to be looking at the biofilm as oppose to free floating bacteria. Bacteria not removed from the biofilm during a water change would continue to replicate and may pose as much a risk. It is a pity that the study does not go further to compare itself to open systems and see if colonisation rates are lower which would support your argument. Against this one can also argue that a stable biofilm with non-pathogenic bacteria, which I'm postulating may be the case if you don't do a water change, would be more resistant to growth of pathogenic bacteria as many bacteria produce bactericides to eliminate competition- pure hypothesis though. For your argument would be that reducing the bacterial load in the water would reduce the colonisation as oppose to replication of bacteria in the biofilm. Strong argument but pity the study didn't go further- note it only indicates potential for reinfection. But hey, if you're reading that at 15, then you're way ahead of the game.

Think I might have found some one with alot of answers but not a subscriber-http/www.barrreport.com/- any help?
article on restoration ecology and one on fish waste might have some good answers but can't access it.

 

[geo7x]

Yes I agree what I provided is not hard evidence just thought it was an interesting prospect worth considering.

From the way I interpreted it, it would appear that perhaps there can be too much of a good thing when it comes to biofilm.

From what I have researched (including unsuccessfully trying to interpret further articles) it appears that in water treatment and distribution (for people) chlorine is used to reduce levels of biofilm, therefore reducing the risks of pathogens such as e coli building up if the previous article is anything to go by. In aquariums, we obviously dechlorinate our water, therefore there is surely nothing in aquariums to inhibit the growth of biofilm and various harmful pathogens that may be in it. Due to this, as fishkeepers our only way of keeping this level down would be to do do water changes by removing water, which in turn reduces the levels of biofilm (and harmful pathogens) slightly, and replace it with water from the tap which is free of such pathogens, biofilm, and I would presume free of nutrients for such bacteria to feed on, therefore diluting the bacteria in the biofilm of the aquarium.

Without doing water changes surely an aquarium would just become an uncontrollable breeding site for harmful bacteria within biofilm?

 

[Spider Pig]

Yes I agree what I provided is not hard evidence just thought it was an interesting prospect worth considering.

From the way I interpreted it, it would appear that perhaps there can be too much of a good thing when it comes to biofilm.

From what I have researched (including unsuccessfully trying to interpret further articles) it appears that in water treatment and distribution (for people) chlorine is used to reduce levels of biofilm, therefore reducing the risks of pathogens such as e coli building up if the previous article is anything to go by. In aquariums, we obviously dechlorinate our water, therefore there is surely nothing in aquariums to inhibit the growth of biofilm and various harmful pathogens that may be in it. Due to this, as fishkeepers our only way of keeping this level down would be to do do water changes by removing water, which in turn reduces the levels of biofilm (and harmful pathogens) slightly, and replace it with water from the tap which is free of such pathogens, biofilm, and I would presume free of nutrients for such bacteria to feed on, therefore diluting the bacteria in the biofilm of the aquarium.

Without doing water changes surely an aquarium would just become an uncontrollable breeding site for harmful bacteria within biofilm?

Possibly but you would need to know whether harmful bacteria are more likely to breed than beneficial bacteria. As I said a number of bacteria produce bactericides to combat competition, then there is the limitation imposed by nutrients. I'm not sure how much bacteria require micronutrients but these would be replenished by water exchange. Sterilising the environment may allow pathogenic bacteria to breed faster than beneficial bacteria- such as intestinal infections after antibiotic treatment in humans. We would need to know the types of bacteria present in the tank, replication rates, virulence and whether any bactericides are produced.

I think I've found the idea I have been trying to get across- a low light low tech tank. From what I have seen this seems to be what Walstad was up to but I would need to have a look at her book. Tom Barr looks like the don in this area:
http/www.barrreport.com/articles/433-non-co2-methods.html- quite an extensive thread but in this he suggests that plants adapt to the low CO2 by switching on genes to create new enzymes to cope with low CO2. Adding new water adds CO2 and tricks the plants into switching these off again.

http/www.aquariaplants.com/lowlighttank.htm. This chap suggests that water change can actively disrupt the balance in these tanks. I've seen that there's talk of allelopathy and these chemicals build up in the tank helping to control algae, but on Barr's website there is a report that pretty much knocks this on the head.

http/lowlightlowtechplanted.blogspot.com/

I think I just happened to set up a tank like this- I have 50w for 180L which is just over 1 wpg, and planted with mainly fast growers and few slow growers. Probably stocked on the heavier side though, but as I said, no problems yet. A recommended nitrate level of 20-30ppm is suggested but I am reluctant to let it get that high.

I think Walstads book will have most of the answers to this question but may try to ask Tom himself.

 

[TwoTankAmin]

The other thread on this topic in the newbie area motivated me to spend more time than sensible trying to find scientific articles dealing with this topic. I have looked at 100s of links trying to find anything that I thought remotely translated to the typical fw aquariums we hobbyists keep.

Tonight I finally stumbled across this article which deals with nitrate and its effects on the liver of the common carp:

HISTOPATHOLOGICAL CHANGES IN THE KIDNEY OF COMMON CARP, CYPRINUS CARPIO, FOLLOWING NITRATE EXPOSURE.

Abstract: Cyprinus carpio, common carp was exposed to subleathel concentration (12 ppm) of nitrate (KNO3) under acute and chronic static bioassay conditions. The resultant histopathological changes in the liver were recorded by light microscopy. LC50 values of nitrate, according to Reed-Muench method, were 995 ppm for 48 hrs and 865 ppm for 96 hrs. For the acute tests, the fish were exposed to 12 ppm of nitrate for 1,2 and 4 days. For chronic tests, the fish were treated with 12 ppm of nitrate for 8, 16 and 32 days. Control fish were maintained in parallel with the experimental groups. Increase in Bowman’s space, degeneration of glomeruli, shrinkage of proximal tubule cells with pycnotic nuclei, increased tubular lumen and increased in intratubular hematopoietic tissue were the most significant changes observed in fish kidney after nitrate exposure. The effects were time dependent being more pronounced in acute treatments. The present investigation illustrates that presence of high concentration of nitrate in water are stressful to fishes.

The entire text of the article is available here and is an interesting read: Journal of Research (Science), Bahauddin Zakariya University, Multan, Pakistan.
Vol.15, No.4, December 2004, pp. 411-418 ISSN 1021-1012

 

[Spider Pig]

Good evidence of the toxicity of nitrate. Have to say that the results do sound a little extreme however.

"Acute and chronic treatment of fish with 12 ppm nitrate revealed substantial changes in fish behavior. These involved abrupt and sluggish swimming movements in various directions indicating an avoidance response. Occasional jumping and hitting the walls of aquaria were also noted. As far as general condition of fish is concerned, rapid scale loss, especially from head region, was observed in acute treatment groups. These changes were more pronounced during the initial hours of exposure of fish to nitrate. Surprisingly, defecation by almost all challenged fish was recorded with in 30 minutes of exposure to nitrate Excessive secretion of mucous by treated fish was also observed which was particularly marked in the fish exposed to acute nitrate treatment where aquarium water became cloudy. Thereafter the fish tend to recoverfrom the disturbed state in due course of time and the frequency of abnormal behavior decreased. However, it stayed higher than in the control group at the end of both acute and chronic exposure."

To the best of my knowledge 12ppm is not an uncommon level of nitrate for aquariums. Certainly this would suggest that anyone keeping fish in planted aquaria where they try to maintain a nitrate level of 30ppm is damaging their fish.

One of the main criticisms I would have of the study is that there is no measurement of ammonium or nitrite levels. These are known to be more toxic than nitrate and will be present as a waste product of fish metabolism, and so could be the cause of the histological changes occuring. There is no information regarding filtration available and so if the aquariums are bare then the ammonia concentration will just continue rising. I was unclear whether they completely changed the water every 24 hours or whether they just tested it and topped up the nitrate. If the former then that is sure to be stressful to the fish.

The source of this article also doesn't appear to be a peer reviewed journal.

This also doesn't alter the contention of this thread that water changes are not necessary when nitrate levels are 0. I refer you again to the concept of low light low tech tanks.

 

[andywg]

I know this is an 18 month dead necropost, but on the Tilapia subject, I understand that our very own Space_Monkey is working at a fish farm which rears Tilapia at the moment and he mentioned they are a closed system (no water changes).

Hopefully he might find some more out and post some info here (such as how they look after their water quality) so we can see the application of the above paper first hand.

 

[OohFeeshy]

Space seems to have vanished into the wild blue yonder...

 

[Ace Of Spades]

Space seems to have vanished into the wild blue yonder...

I see him on chat time to time, lets hope he hears our call. And If I see him in Live Chat, I'll direct him in here...

 

[Jonathangerous]

It should be noted that in closed systems, especially in an aquacultural setting, the nitrogen cycle is very much microbiologically different from what we're used to in the home hobbyist trade, simply due to the vast fluctuating quantities of nitrogenous wastes released. This also increases the feasibility of utilizing denitrification reactors, which is something the normal freshwater hobbyist is not used to seeing.