Water Changes

[aussieant32]

Easy question. How often do you do water changes and why do you do them?

 

[NickAu]

Easy answer
50% every week.
Because its good for the plants and fish.

 

[aussieant32]

is it though? That was the answer I was expecting.

What do you base it being better on?

We generally test for 3 things in freshwater, ammonia, nitrite and nitrate. Now everyone's tap water is different and so are their tanks. 50% per week may be what you have worked out, but it might not be for others. I will try to explain.

My tap water has 5ppm nitrate in it. For most plants to thrive a nitrate level around 10-40ppm is ideal. So is reducing my nitrate every week really 'good for the plants'?

The same goes for fish, surely they live much longer and are much healthier in the water they prefer, not necessarily in freshwater. Most of the fish we keep are not suited to dechlorinated tap water. Anyone know 'old mate' with the 12 inch clown loaches that get a water change twice a year?

This came up as I was talking to some fishkeepers today and they all pretty much said they change all their tanks 50% each week. I go with the approach of keeping the water levels where they need to be as opposed to changing it every week cause that is the thing to do. After 1-2 months I know each of my tanks. I know how often and how much water to change. My 40L usually hits the 40ppm mark after 7 weeks and a 40% change takes it down to around 10ppm for example. Ammonia and nitrite never move past 0.

As long as the water parameters are where they need to be, why change them every 7 days? What is it that is being achieved by adding fresh tap water?

I find it an interesting discussion none the less, would love some counter points to consider.

 

[Byron]

This is I think the third thread this week to deal with water changes (the other two were indirectly included in other discussions).

First, when it comes to maintenance of an aquarium, absolutely nothing is as important as regular partial water changes. A water change is the only means of removing substances that cannot be filtered out. Pheromones, allomones, urine, dissolved waste--these remain in the water until we siphon them out. And, stable water chemistry is, or should be, the result from more water changes, not fewer.

As a simple example...a fish as small as a tetra releases urine in the level of 1/3 of its body weight every day. Fish urine does not contain ammonia like other animals (ammonia is given off via the gills), but this water that the fish pulled into its body via osmosis through every cell is depleted and just "stale water" in effect. Eventually, the fish is swimming in it own urine, and that of the other fish. The only way to get rid of this is via water changes.

Many discus breeders will change the water in their fry tanks at a rate of 90-95% once, sometimes even two and three times, each day. The fry develop much faster and are much healthier, all due to water changes.

Second, using test results as the basis for water changes, if this means only doing them when levels for say nitrate rise, is not sufficient; by then the "damage" is being done, fish are being affected. Regular and substantial water changes will ensure stability in water chemistry much more than not doing them, or not doing sufficient. You write:

My 40L usually hits the 40ppm mark after 7 weeks and a 40% change takes it down to around 10ppm for example.​

The fish are being negatively affected; nitrate should never be above 20 ppm, and always as low as possible. Nitrate is toxic to fish, only not as quickly as ammonia or nitrite. But nitrate weakens fish generally, at the very least, and is now being linked to some specific issues. You should be doing sufficient water changes to keep nitrate at 10 ppm, since it clearly can be this low; having 5 ppm in the source water is not the best situation, but that is low enough that you should be able to work with it, and if you see nitrate at 10 ppm clearly you can. My tanks are in the 0 to 5 ppm range, and have been for years. This is what you want, stability and consistency, with nitrate as low as possible. None of the species we keep in aquaria occur in natural waters with nitrate above 1 or 2 ppm, and many are zero. Through evolution, fish species have been designed to function best in such water.

You mention plants needing nitrate...no, most do not. Most aquarium plants prefer ammonium (ammonia) as their source of nitrogen, and they will take this up very rapidly, out-competing the Nitrosomonas bacteria even. Floating plants are often termed "ammonia sinks" because of their ability to take up so much so quickly. This is why they are beneficial in all tanks, but especially new ones. Plants only turn to nitrate when ammonium is insufficient; this is because plants have to change the nitrate back into ammonium internally, and this takes more energy, so it is something of a last resort. Having said that, there are a few species that through evolution have adapted to using nitrate more readily, but they are not the majority.

I change at least 50% of the tank volume, but usually it is closer to 60-70% of the tank, once each week, without fail. I have eight tanks in my fish room, and though I do not do tests regularly, only periodically, ammonia and nitrite have never been above zero, nitrate has never been above the 0-5 ppm range on the API test card, and the pH never fluctuates more than a couple decimal places. I have kept the charts of test results for several years, and I can go back for each tank and see no variation. This is the goal. The fish will be healthier, guaranteed.

Byron.

 

[drewzaun]

Easy question. How often do you do water changes and why do you do them?

Easy question, easy answer. You’re volume and frequency of water changes should be sufficient to keep conditions stable.

I find many advantages to smaller volumes more often than 1 big one once a week. If you’re using municipal water there are many variables outside your control and sometimes your knowledge that could effect water chemistry, and if you’ve inadvertently added something bad in your tank it’s more diluted and less likely to cause problems and easier to remove. Sometimes the amount of chlorine is different. Sometimes they change brands and maybe they mistakenly add the same amount as always though the new batch is more concentrated. Sometimes you have a house fire down the street, and the fire department pumps 15,000 gallons through the hydrants, stirring up the crap that settles in the pipes that you don’t want in your tank. The water company does this twice a year (hydrant flushing), and the water is brown and stinky and they advise not to drink it, but you don’t get a notice when there is an emergency, or a mistake.

Also if something happens in your life and you miss a change it is far less troublesome than if you miss your weekly 75%er.

Anyway, consistency is key, many species of fish can adapt to water conditions completely different than what they evolved in, but not many fish can do well in conditions that are in a constant state of flux, so change water at the volume and frequency that consistently provides the conditions your fish thrive in.


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[aussieant32]

spot on for me mate. Exactly what I was getting at. Stable water is more important than fresh water in my opinion

 

[drewzaun]

spot on for me mate. Exactly what I was getting at. Stable water is more important than fresh water in my opinion

Well, yes, but remember the water in your tank isn’t stable, fish and other biological organisms are constantly adding and taking out nutrients and waste products. Also water is a solvent and is performing chemical reactions to one degree or another, dissolving some compounds and creating others as the chemistry demands.

Best bet imo is to change small amounts every 2-3 days, keeping the water as stable as possible. I think it’s even more important to change every 2-3 days if your changes are 50% or more of the system volume at one time, since you have a greater potential to alter the water chemistry with large volume changes, you want there to be less of a change, so less time allowed for biological and chemical forces to act on the water.

However, and this is important to, nobody has the One Right Answer...so if your tank has been running for a year or more and everything is great, what you’re doing works for you. Consider what others say and why, but it’s your tank and your circumstances.


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[aussieant32]

correct and that's why I asked. Was curious as to why people do the changes they do. Out of habbit or need

 

[NickAu]

Byron explains why weekly water changes are a must.

As you are keeping a Betta heres more advice,

Unless you do regular 50% water changes at least once a week your fish will have health issues such as fin rot. People think Bettas are these hardy fish that can live in a muddy puddle, News Flash, that is wrong. Modern day Betta Splendens are not hardy fish anymore due to the way they are line bred etc, ( line breeding- the selective breeding of animals for a desired feature by mating them within a closely related line, usually Brother and sister )

 

[AbbeysDad]

spot on for me mate. Exactly what I was getting at. Stable water is more important than fresh water in my opinion

But the only way to maintain stable water chemistry is with routine periodic water changes. We start a tank with 'pure' potable drinking water from tap or well. Then we add fish and fish food. Waste is created and decomposes into numerous compounds. We use a filter, but although a filter may remove detritus that we can see, it still breaks down and pollutes the water column.....so the solution to pollution is dilution!
The routine partial water change is a must to maintain a stable water chemistry.

 

[AbbeysDad]

Oh...and I forgot to mention that fish and plants need and use minerals from the water...minerals that are only replaced by periodic partial water changes.

From time to time, less experienced fish keepers question the need for partial water changes. On another forum we had a fellow swear that he never did water changes and his fish were just fine, had a 'normal' life span, and even bred. Of course, I'm pretty sure he didn't realize that with proper care and feeding, most tropical fish can live about 10 years!
Fish can somewhat adapt to degrading water quality, but it will shorten their lifespan and eventually may promote illness and disease.
I'm in the camp with experts that agree that they rarely, if ever, use medications - that the best 'cure' for fish is fresh water.
Finally, I think too many less than serious hobbyists get a tank and either never understood proper maintenance or lose interest and stop doing water changes. In time, the fish die off and the tank ends up in the basement, garage, or on Craig's list!
What's really sad is that fish just don't get the respect like other pets like cats, dogs, rabbits, birds, etc. and get mistreated with little regard...."oh, it's just a fish". Imagine keeping a dog or a rabbit in a crate or a cage, feeding it poorly and never cleaning the crate or cage!!!!

Do your fish a favor and do those weekly partial water changes religiously!

 

[Byron]

spot on for me mate. Exactly what I was getting at. Stable water is more important than fresh water in my opinion

that's why I asked. Was curious as to why people do the changes they do. Out of habbit or need

These comments indicates that you either didn't read my post, or didn't understand any of it. You cannot have stable water chemistry that is in the best interests of the fish [meaning, allows them to be healthier] without water changes, and there is plenty of scientific evidence that the more water changed the healthier will be the fish. There is no argument; you might as well try to convince me that evolution is a hoax, when I have the evidence of current evolution of fish species.

Best bet imo is to change small amounts every 2-3 days, keeping the water as stable as possible. I think it’s even more important to change every 2-3 days if your changes are 50% or more of the system volume at one time, since you have a greater potential to alter the water chemistry with large volume changes, you want there to be less of a change, so less time allowed for biological and chemical forces to act on the water.

This is contrary to the scientific evidence.

However, and this is important to, nobody has the One Right Answer...so if your tank has been running for a year or more and everything is great, what you’re doing works for you. Consider what others say and why, but it’s your tank and your circumstances.

Your conclusion here does not follow. How do you know things couldn't be better? And why would you want to keep any living creature, even a fish, in conditions that are not as good for the fish as they could be? Aquarists need to be more responsible.

Also if something happens in your life and you miss a change it is far less troublesome than if you miss your weekly 75%er.

This is not true either. The larger regular changes create a more stable biological system, so missing a change actually has less impact negatively. The science is proof of this.

 

[aussieant32]

So most of you think rather than adding what the fish and plants need, its better to add tap water? Tap water in which you most likely have no chemical breakdown of so have zero idea what is in it?

I mean who has the levels of nitrate, potassium, iron, nitrogen, phosphorous of their tap water at hand? How do you maintain these levels if you don't know what you are adding or taking away?

I do very little water changes in my reef tanks, rather I dose everything the inhabitants need. I have not added fish in 7 years and only had 1 die and not lost a coral or invert since the tanks been running.

Why is freshwater so different? I am genuinely asking this question as I am curious why water changes are so important in freshwater, whereas in reef keep which is arguably much more 'touchy' than freshwater adding the desired elements works so well.

I have only just gone back to having a freshwater tank so am asking for that reason.

I will leave a link to a video below that seems to follow my thoughts mostly, interesting to hear some opinions

 

[drewzaun]

So most of you think rather than adding what the fish and plants need, its better to add tap water? Tap water in which you most likely have no chemical breakdown of so have zero idea what is in it?

I mean who has the levels of nitrate, potassium, iron, nitrogen, phosphorous of their tap water at hand? How do you maintain these levels if you don't know what you are adding or taking away?

In the States at least, you get a report periodically from your water company with complete analysis of your tap water. You can request these more often and sometimes the results are on the internet. You can also test your water yourself, like you would with aquarium water.

If you keep fish that enjoy your tap conditions a lot of the work and worry is taken away, you just have to condition your change water

I do very little water changes in my reef tanks, rather I dose everything the inhabitants need. I have not added fish in 7 years and only had 1 die and not lost a coral or invert since the tanks been running.

Why is freshwater so different? I am genuinely asking this question as I am curious why water changes are so important in freshwater, whereas in reef keep which is arguably much more 'touchy' than freshwater adding the desired elements works so well.

I have only just gone back to having a freshwater tank so am asking for that reason.

So how do you export waste products? I’ll wager you have a protein skimmer? They pull a ton a garbage out of your water, but won’t work in freshwater. You may also have a nice isopod/copepod colony in your live rock, which freshwater also doesn’t have.

Many reefers use a controller with automatic dosing pumps, which is virtually unheard of in freshwater, I’m guessing you do as well? Otherwise the constant testing and micro dosing would be tedious, at least for me. Without changing water I don’t see how else you get minerals etc into the tank?

In planted tanks it’s common to OD fertilizer all week and then do a big change at the end of the week to “reset”, before anything bad happens,as opposed to constant monitoring and micro dosing. As the hobby expands maybe Neptune or some other company will add probes that read common ferts and planted tanks will have controllers and sumps too. I like that idea, but I’m a bit of a tech nerd. Then again, I’m new to plants, maybe they do?






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[drewzaun]

Your conclusion here does not follow. How do you know things couldn't be better? And why would you want to keep any living creature, even a fish, in conditions that are not as good for the fish as they could be? Aquarists need to be more responsible.

This is the internet, full of internet experts. I offer advice that I’ve learned over my time in the hobby. Things that have worked for me personally for years. Some I learned on my own, some from other hobbyists, some from professionals with lots of letters after their names that I’ve been fortunate to work with over the years.

I think it’s important to note there is no one way to do things, none of us have the absolute answer for everyone, and over time I’ve seen people get persuaded by different internet experts claiming to know it all and they start changing things from one philosophy to another, and wind up crashing their tanks.

Once in a while I like to add that if you don’t have a problem you’re trying to correct, take what everyone says with a grain of salt, and apply new knowledge cautiously.

None of us are truly experts. Some can acknowledge that, some can’t. Ymmv



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