Another "No Water Change" Fish Tank

My 3 and 5 year-old angels haven't even gotten used to water changes yet........sigh. They always hide in the lower back corners. I just have picky fish.

 

I don't want to take this interesting discussion to semantics but it was initially said:

I merely wanted to point out that there is natural water changes that happen in these systems through rain, water movement, ground absorption, run off etc.


Obviously water changes are different than that which occurs in nature; but that is the best way we have (cheapest?) to replicate the water changes that actual do happen in nature. We actually are just trying to replicate natural processes with our limited resources. If you are arguing that it is different due to the regularity (50% every week etc.), then I would like to mention that this is just a human creation for ease of completion.

there is nothing wrong with doing lots of water changes. It works for people who are disciplined and have good water (my tap is >8ppm ammonia)- but don’t be so quick to assume it’s the only way. nature can also work in your favor like in Old’s tank to reduce water changes. In natural ponds nitrates are 0 from bacteria and plants not from rainfall .

 

My main concern with the absence of water changes in a closed system is not with a build up of nitrates or depletion of minerals but rather the accumulation of microorganisms. Aquarium water is packed full of bacteria, algae spores, parasites and other organisms at far greater densities than are found in the natural environment. This density (as well as the density of other microscopic particulates) is why studies have found that typical UV sterilisers designed for aquariums are not powerful enough to significantly reduce their numbers and why regular partial water changes are important.

How is this addressed in a closed system without water changes?

 

there is nothing wrong with doing lots of water changes. It works for people who are disciplined and have good water (my tap is >8ppm ammonia)- but don’t be so quick to assume it’s the only way. nature can also work in your favor like in Old’s tank to reduce water changes. In natural ponds nitrates are 0 from bacteria and plants not from rainfall .

Never said there was issues with doing lots of water changes. And I never assumed it was the only way and never stated as such. I'm sorry if it came across that way. I first thought zero water changes were possible. Now, I think the build up of trace minerals has been overlooked. The OP then cleared that up by stating that he only tops off with distilled water to which I then brought up the concern about all the nutrients fish and plants need that they might not be receiving with distilled water. He said the minerals would come solely from the food. I'm not sure that is a sound practice, but I don't have any information/studies to the contrary. That is why people add back minerals into aquariums with just distilled water. I would think analyzing and calculating the necessary foods would be more tedious then just doing a water change, but that is just my opinion. I can theoretically see this working.

I didn't say 0 nitrates were from rainfall? What was conveniently omitted was the entire water change process listed that occurs in nature. Agreeably there is bacteria and plants in nature that help with biological processes. But to ignore the other plausible factors of zero nitrates is misrepresenting the information slightly.

I completely agree to defer to nature as much as possible.

 

My main concern with the absence of water changes in a closed system is not with a build up of nitrates or depletion of minerals but rather the accumulation of microorganisms. Aquarium water is packed full of bacteria, algae spores, parasites and other organisms at far greater densities than are found in the natural environment. This density (as well as the density of other microscopic particulates) is why studies have found that typical UV sterilisers designed for aquariums are not powerful enough to significantly reduce their numbers and why regular partial water changes are important.

How is this addressed in a closed system without water changes?

Interesting thought. This reminded me of a something similar I came across previously.

I read a pretty interesting study conducted in Chicago's Shedd Aquarium regarding the impact of water changes on the aquarium microbiome. In summary: the study found that the diversity and evenness of the bacterial community significantly increased following a water change, which was indicative of a significant reduction in the relative abundance of dominant taxa that made up the stable microbial assemblage prior to exchange. However, it didn't seem to have resulted in any significant health outcomes for the resident plants of animals of the aquarium. Maybe over the long term it would make a difference or maybe it wouldn't be of consequence.
*Also I believe that this study was done in an aquarium that far eclipses the volume in the standard home aquarium. So that has to be taken into account. The effects of all actions taken (or not taken) in our tanks have a magnified effect.

Interesting stuff, I enjoy reading everyone's ideas!

 

Agreeably there is bacteria and plants in nature that help with biological processes. But to ignore the other plausible causes of zero nitrates is misrepresenting the information slightly.

I completely agree to defer to nature as much as possible.

I have published scientific papers on nutrient cycling in natural systems and that was not a misrepresentation

 

I have published scientific papers on nutrient cycling in natural systems and that was not a misrepresentation

Ok. Lets move on...

I would definitely love to read your papers on nutrient cycling if I could. Sounds very interesting especially when I am trying to represent a natural ecosystem in my current tank. (Or as close as possible) I'm sure others would probably interested as well, especially in this discussion.

 

This is actually I question I was going to ask at some point. Do we over do water changes if nitrate levels are stable. Many people insist that water changes are required not just to control nitrate but refresh minerals in the tank. I guess from peer pressure I do water changes once a week or so and measure nitrate once every 4 or 5 weeks now but I keep thinking I do more harm than good to do water changes. All of my tanks are planted but they have standard shop substrate. The tank that does the best (as always) is the guppy tank. It has very low algae and solid plant growth without co2. The tank with co2 swings back and forth with hair algae (I think when I trimmed all the vals and through out most of the hornworth I triggered some imbalance that needs to be re-established - in case you ask this was to allow light to reach the bottom and after the cutting the sword plants on the bottom took off).
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But if I suddenly stop or reduce water changes how can I tell if things are going to fall apart before they fall apart (this is sort of the fear - now that I have a routine will a sudden change upset the balance).
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I noted above the guppy tank seems to have the best balance with regards to plant growth and algae but it is also the most over populated because well - guppies are guppies...

This is such a great thread and I’m pondering the same issues as jake37. My 75 g was growing like a jungle last summer and now it’s struggling and I’ve lost a few plants. Some months ago I started doing a larger weekly WC and have noticed nitrates becoming lower and lower.
Adding the complete range of Seachem fertilizers has definitely boosted plant growth. But I can’t decide if I should continue a 50% WC a week and dose plenty of ferts or try going back to a smaller WC.

 

This is such a great thread and I’m pondering the same issues as jake37. My 75 g was growing like a jungle last summer and now it’s struggling and I’ve lost a few plants. Some months ago I started doing a larger weekly WC and have noticed nitrates becoming lower and lower.
Adding the complete range of Seachem fertilizers has definitely boosted plant growth. But I can’t decide if I should continue a 50% WC a week and dose plenty of ferts or try going back to a smaller WC.

Finding the perfect balance is the most difficult part of keeping our tanks (both fish and plants) healthy. A heavily stocked tank needs bigger water changes. If your 75 gallon is lightly stocked it may not need a 50% water change each week. A smaller one may work just as well. If one chooses to go with smaller weekly water changes I will still recommend doing a much bigger one once a month. I call this water change a reset.

Gradually things build up if small water changes are done each week. It may take a long time for these things to build up enough to start causing problems. The one bigger water change each month removes them and prevents problems before they have a chance to start causing problems. In my humble opinion prevention is much better than waiting until a problem shows up and then having to deal with it.

 

Finding the perfect balance is the most difficult part of keeping our tanks (both fish and plants) healthy. A heavily stocked tank needs bigger water changes. If your 75 gallon is lightly stocked it may not need a 50% water change each week. A smaller one may work just as well. If one chooses to go with smaller weekly water changes I will still recommend doing a much bigger one once a month. I call this water change a reset.

Gradually things build up if small water changes are done each week. It may take a long time for these things to build up enough to start causing problems. The one bigger water change each month removes them and prevents problems before they have a chance to start causing problems. In my humble opinion prevention is much better than waiting until a problem shows up and then having to deal with it.

Thanks so much for the reply!
I do think I’m going to try a few months of smaller water changes with a larger “reset” change once a month.
I’m horrible at figuring out stocking but it is probably under stocked. But I like it that way.

 

Thanks so much for the reply!
I do think I’m going to try a few months of smaller water changes with a larger “reset” change once a month.
I’m horrible at figuring out stocking but it is probably under stocked. But I like it that way.

That's what I do! I do 3 15-27% a month and then one 45-62% once a month.

 

This is actually I question I was going to ask at some point. Do we over do water changes if nitrate levels are stable. Many people insist that water changes are required not just to control nitrate but refresh minerals in the tank. I guess from peer pressure I do water changes once a week or so and measure nitrate once every 4 or 5 weeks now but I keep thinking I do more harm than good to do water changes. All of my tanks are planted but they have standard shop substrate. The tank that does the best (as always) is the guppy tank. It has very low algae and solid plant growth without co2. The tank with co2 swings back and forth with hair algae (I think when I trimmed all the vals and threw out most of the hornworth I triggered some imbalance that needs to be re-established - in case you ask this was to allow light to reach the bottom and after the cutting the sword plants on the bottom took off).
-
But if I suddenly stop or reduce water changes how can I tell if things are going to fall apart before they fall apart (this is sort of the fear - now that I have a routine will a sudden change upset the balance).
-
I noted above the guppy tank seems to have the best balance with regards to plant growth and algae but it is also the most over populated because well - guppies are guppies...

Funny, I have blue gravel substrate I use for one of my guppy tanks and it has some of the best plant growth I’ve seen! Regular substrate, no root tabs, I’ve thrown random trimmings in there that do fantastic !

 

I actually enjoy providing my fish with fresh water, they are just so happy after a good water change and they've often spawned right after our even before I get the water filled again.


Thanks Old. I don't know exactly what organic matter would build up that the plant doesn't use, but the plant would only use whatever it needs to grow. Or should I say grow as fast as it receives light and certain fundamental minerals and such. But how do you match the amount of nutrients in the fish food to accommodate the plant. Or what about the stuff the plant doesn't intake as much? Wouldn't that continue to build up?

Also, i'm thinking about KH depletion. Do you add baking soda or something to buffer KH and GH? What do you mean the plant roots maintain bi-carbonate? Do you mean use up and not provide?

angel...

You're beginning to test my memory as far as my high school chemistry classes. But, here goes: The KH chemicals that make up carbonates like oxygen and carbon dioxide are in the air. The bicarbonates that prevent sudden changes in the water chemistry, like calcium, magnesium and zinc are in many fish foods. So, you have the elements to keep the water chemistry steady. I'm afraid my knowledge of the chemistry of water is limited. The relationship between the plants and fish will maintain good water conditions as long as you don't use tap water to top off the tank. Distilled or Reverse Osmosis water are the only options.

Old

 

Tx Old, not trying to give you a hard time I'm only wondering about how you ration out nutrients in the fish food to the amount the plant uses? Like what about the nutrients that the plant doesn't use as much, they would continue to build and build in the water?

 

I have to admit, when I first saw the title of this thread, I thought Old Salt was messing with us. He's always one to reply with, "Your problem will be corrected by large weekly water changes of at least 50%." I was shocked when I saw that not only was he serious, he was talking about his own tank!
Also in all the discussion don't forget that while immersed aquarium plants utilize nutrients from the water and substrate, these are actually drinking the water to get what they need from it. That has to change things somewhat as far as what goes in and is left out. These plants have to take up the water, use it, and release what they don't need through their leaves. And by the looks of them, they are getting all they need!
I still wanna see the guppies though

 

I'm not worried about the plant, agreed, it looks like it's doing alright But my concern is the excess nutrients and such building in the water. If they are not being used up as fast as the fish food is adding it, with 0 water changes, it will eventually get so full. At least I think it would. Too much organic and thickening the water.

Maybe for guppies it's ok, but I would never try it with soft water loving fish. They can adapt, but too much stuff in the water is not good for them.

 

I'm not worried about the plant, agreed, it looks like it's doing alright But my concern is the excess nutrients and such building in the water. If they are not being used up as fast as the fish food is adding it, with 0 water changes, it will eventually get so full. At least I think it would. Too much organic and thickening the water.

Maybe for guppies it's ok, but I would never try it with soft water loving fish. They can adapt, but too much stuff in the water is not good for them.

I hear you. I didn't even mean to direct my post at anyone, just adding my .02 to the discussion. I doubt Old Salt would try it with angels either. Maybe the guppies do well since they love hard water.

 

I hear you. I didn't even mean to direct my post at anyone, just adding my .02 to the discussion. I doubt Old Salt would try it with angels either. Maybe the guppies do well since they love hard water.

Oh ok no worries I just worry about other ppl reading this and they think it's ok to do it without thinking everything through. Maybe it works for Old, I just don't see it working longterm for all tanks. I realize he is not advocating that either, but just had to ask the questions.

 

I have to admit, when I first saw the title of this thread, I thought Old Salt was messing with us. He's always one to reply with, "Your problem will be corrected by large weekly water changes of at least 50%." I was shocked when I saw that not only was he serious, he was talking about his own tank!
Also in all the discussion don't forget that while immersed aquarium plants utilize nutrients from the water and substrate, these are actually drinking the water to get what they need from it. That has to change things somewhat as far as what goes in and is left out. These plants have to take up the water, use it, and release what they don't need through their leaves. And by the looks of them, they are getting all they need!
I still wanna see the guppies though

Hello Mag...

Will see what I can do to provide some pictures.

Old

 

So this raises another issue - if we watch the tds of the water over time does that tell us anytihng ? I have 4 tanks - my tap water today was 112 - the 120 which I change 25% twice a week is 157; the guppy tank (which is over populated with guppies) is 134; the whatever tank is 157 (it had a lot of cyano which I treated with chemiclean); and the nannacara tank is a whopping 257 (that is the tank the nitrate never goes above 5).
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What can we say about these tanks. If I don't do any water changes on the guppy tank and hte tds stays below 150 does that mean it has a self sustaining ?

 

So this raises another issue - if we watch the tds of the water over time does that tell us anytihng ? I have 4 tanks - my tap water today was 112 - the 120 which I change 25% twice a week is 157; the guppy tank (which is over populated with guppies) is 134; the whatever tank is 157 (it had a lot of cyano which I treated with chemiclean); and the nannacara tank is a whopping 257 (that is the tank the nitrate never goes above 5).
-
What can we say about these tanks. If I don't do any water changes on the guppy tank and hte tds stays below 150 does that mean it has a self sustaining ?

I've been watching this thread and enjoying it as a lurker and think I would like in on it now lol. All the points raised here are very good, on both sides of the table.

Disclosure; on most of my tanks I do water changes weekly, but they have occasionally gone a stretch, and I test them before maintenance. I don't have anything set up other than fry tanks today I would worry about if they HAD to go up to 2 months with just top offs. Probably longer but I haven't seen that happen yet.

I have a few tanks, and aI'm for as "self sustainable" as possible but still attractive and "maintenanceable". The thing about me is due to my occupation, I could be gone for a while, whenever, and back weeks to months later. I try to find the ways to make my hobbies and chores as easy on my wife and children as possible. Due to this curiosity I have slowly built up to a ~15 part testing kit (including all the normal stuff, phosphate kh,gH, copper, iron and other Trace and heavy metals), and a TDS meter.

I don't test to see if I need to do a water change, I know I don't. I test to see how long it may be projected until I would need a water change, while I'm changing water anyhow. The most recently water changed tank should be the one that will last the longest if it must go untouched.

I have built up the battery of tests and the TDS meter to try and prove mathematically what actually happens in my tanks from week to week, month to month. I don't fertilize, have very soft water and grow as much as I can. In one tank I have had the longest, I have found that even at 30 days with top offs only my TDS only increases about 10% upon testing, the only detectable increases chemically are phosphate, and hardness. The hardness likely increases due to the rapid evaporation rate in that tank, combined with the soft water starting parameters. The phosphate increases due to over feeding I'm sure. The planting keeps the nitrogen biproducts at or near zero.

I cannot account for about 25% of my TDS mathematically from the tap using the tests I have if I am to take the ppm values at face value, and I cannot account for roughly 50% of my increased TDS over a month span in my example tank. I would feel comfortable saying that the increased(unknown) TDS is likely a form of protein suspended due to waste breakdown or overfeeding, but it may be a bacterial build up showing other trace solids, I don't really know. But I can say I believe a top off only tank would be possible with some tweaking.

That is what most "ponds" are in nature, as they aren't deep enough to reach the water table and do not commonly have any feeding waterways.

If we could come up with a better battery of testing that could account for everything a TDS meter would show I think it would be easy to prove a self sustaining tank, I suspect one missing ingredient is microfauna that could take years to balance given a load of input and output. The downfall to a true self sustaining tank may be it's overall appearance. I find it too hard to look at a tank if I plant it "wildly" and do not clean the substrate, and the substrate is where such micro organisms would thrive and balance.

To figure out if the guppy tank in Jake's example was capable of self sustaining, we would need to find a way to account for all the solids, at the beginning of a month, then at the end of a top off month, look for solids that trended down, look at solids that trended up, and then finally analyze if said solid would cause harm to the fish or affect it's metabolism or adsorbtion/osmoregulation. These would indicate whether a sudden swing upon cleaning the tank a year or two later would be lethal or not, as well as indicate what could be added (or removed) to the tank to keep the trend stable. Using a TDS meter independently of specific testing is about as useless as a recipe that says " 3tsp spices" instead of "1tsp salt, 2 tsp sugar" in terms of sustainability.

 

So this raises another issue - if we watch the tds of the water over time does that tell us anytihng ? I have 4 tanks - my tap water today was 112 - the 120 which I change 25% twice a week is 157; the guppy tank (which is over populated with guppies) is 134; the whatever tank is 157 (it had a lot of cyano which I treated with chemiclean); and the nannacara tank is a whopping 257 (that is the tank the nitrate never goes above 5).
-
What can we say about these tanks. If I don't do any water changes on the guppy tank and hte tds stays below 150 does that mean it has a self sustaining ?

jake...

A 25 percent water change isn't enough to maintain pure water conditions for the fish. A 25 percent water change still leaves 75 percent of the toxins in the water. Your fish and any plants you have will add to the pollutants before your next water change. If you want the fish to be their healthiest, you need to work up to the point you're removing and replacing at least half the water every week. Since you have to get out the gear for the water change anyway, take few more minutes and remove half.

Old

 

That is 25% twice a week which is close to 40% a week. It isn't as simple as removing half. I have a 30 gallon pale and I have to spend 4 hours heating the water after I remove it before I can put it back in...

jake...

A 25 percent water change isn't enough to maintain pure water conditions for the fish. A 25 percent water change still leaves 75 percent of the toxins in the water. Your fish and any plants you have will add to the pollutants before your next water change. If you want the fish to be their healthiest, you need to work up to the point you're removing and replacing at least half the water every week. Since you have to get out the gear for the water change anyway, take few more minutes and remove half.

Old

 

That is 25% twice a week which is close to 40% a week. It isn't as simple as removing half. I have a 30 gallon pale and I have to spend 4 hours heating the water after I remove it before I can put it back in...

Wouldn’t it be quicker to add boiling water from a kettle?

 

I tried that - it didn't work out well. You would have to be here to understand the issue. I put in about 5 pot worth of hot water and raised the temp a few degrees. Part of the problem is temp of the water and raw volume. The bright side is that I could try 50 gallons during the summer. The thing to remember (which you didn't know) is that it takes about 10 minutes to fill the pail with fresh water and then another 8 minutes to pump it into the tank - so doing a second pail will take another 45 minutes (12 minutes to drain the tank into the pail and then pump it to the toilet) so saying it only takes a few more minutes to go from 30 to 60 gallons isn't exactly true.

Wouldn’t it be quicker to add boiling water from a kettle?

 

I tried that - it didn't work out well. You would have to be here to understand the issue. I put in about 5 pot worth of hot water and raised the temp a few degrees. Part of the problem is temp of the water and raw volume. The bright side is that I could try 50 gallons during the summer. The thing to remember (which you didn't know) is that it takes about 10 minutes to fill the pail with fresh water and then another 8 minutes to pump it into the tank - so doing a second pail will take another 45 minutes (12 minutes to drain the tank into the pail and then pump it to the toilet) so saying it only takes a few more minutes to go from 30 to 60 gallons isn't exactly true.

Fair enough. I don’t use buckets anymore but when I did it would only take less than 1L of boiling water in a 12L bucket to raise it to the required temperature. But even in winter here our water is not what I would call icy cold.

 

Fwiw guys, I also age my tap water in reservoirs. If I age water for 24hrs, it's pretty much room temp when I add a stock pot of boiling water. Sometimes I need 1.5 stock pots for each 20 gallon container.

jake37 As far as TDS rising, it is likely protein and organics just biproducts from life that are left behind in the water. Overtime, this continues to build as it accumulates faster than it is removed. Not saying it's impossible, but it's extremely difficult to acheive that kind of balance and can be thrown off so easily with any little variance.

To prove it works is a whole other ball game where you would have to start rationalizing fish food nutrients to plant uptake and filtering to whatever is left behind. Lots of calculation and strick self discipline to stick to procedure is required. And if anything changes, like guppy numbers go up, everything has to be re-calculated.

 

But the mystery to myself is why the tds would be lowest in the guppy tank. I suspect it has something to do with the plants but not sure.

Fwiw guys, I also age my tap water in reservoirs. If I age water for 24hrs, it's pretty much room temp when I add a stock pot of boiling water. Sometimes I need 1.5 stock pots for each 20 gallon container.

jake37 As far as TDS rising, it is likely protein and organics just biproducts from life that are left behind in the water. Overtime, this continues to build as it accumulates faster than it is removed. Not saying it's impossible, but it's extremely difficult to acheive that kind of balance and can be thrown off so easily with any little variance.

To prove it works is a whole other ball game where you would have to start rationalizing fish food nutrients to plant uptake and filtering to whatever is left behind. Lots of calculation and strick self discipline to stick to procedure is required. And if anything changes, like guppy numbers go up, everything has to be re-calculated.

 

But the mystery to myself is why the tds would be lowest in the guppy tank. I suspect it has something to do with the plants but not sure.

Oh I see. Well my TDS rises the fastest in my 90g with deep dirt beds and a lot of organics. No nitrates, but the plants cannot use everything.

 

With no water changes how do you address the buildup of trace minerals that come from just doing top-offs?

Top offs with deionized water. Rain water is earth's natural top offer and it's lacking trace elements.

 

I'm considering turning this no change tank into a normal tank so I can see the fish.


I was OK never seeing the ~20 cories and such but added 3 Black Tiger Darios yesterday and would like to see them.