Need Opinion on Nitrates and Water Change

[Vengified]

As title says, I am wondering if/when I NEED to do water changes on my tank? I am not new, I'm well aware of nitrogen cycle, had one tank 7 months, second tank 4 months, both with healthy fish. Been frequenting forums for months, with multiple threads if you care to check my profile, and I've learned many things.

But now I'm curious about my schedule for w/c. I know it's a general recommendation for weekly w/c, to keep nitrates in check, keep detritus to a minimum, and replace minerals in the water column, and I have done at minimum once a week, usually 2-3 per week, since tank started months ago. I used to have near constant nitrates, that would excess 40ppm if I left it a week. However, now I'm planted to the point I barely get a reading of nitrates after a week (0-5ppm see picture below)

I dont mind the tea colored water either. One picture is the day I put the giant cholla wood in the tank (the other 2 mopani are very aged, and leaching 0-negligible tannins), and the other picture is one week exactly, since I put it in, with a 3rd pic of my nitrate reading (ammonia 0, nitrite 0, pH 7.8). I have been feeding just one time per day, in the evening, generally one cube frozen (thawed) spirulina/brine shrimp, to support 2 honey gourami, 6 guppy males, and PILES of RCS. Plants are hornwort, frogbit, and a couple unknown stem plants.

**TL;DR - What do you guys think on W/C schedule? I know nitrogen cycle, minerals in water, etc, just need thoughts/opinions on what others do in this situation?

>>>DAY 1<<<​

>>>DAY 7<<<​

>>>NITRATES @ DAY 7<<<​

 

[Colin_T]

Do a 75% water change and gravel clean once a week and leave it at that. The water change and gravel clean will dilute any microscopic organisms in the water and keep the fish healthier.

 

[Byron]

I concur with Colin. A regular weekly water change is minimal, and the volume should be at least 50% but more is not going to hurt and will benefit. I do in the region of 65-70% of each of my tanks every Sunday, without fail, and have for years. There are substances in the water that no filtration can remove, and that cannot be tested by our basic test kits. And while the stocking of the tank and its volume can impact water changes, it is better to get into a good habit and stick to it. The more water you change, the better--meaning healthier--the fish will be. The only time this is not the case is when a tank has been allowed to deteriorate; a massive water change can cause serious issues for reasons involved with chemistry. But with regular substantial water changes this situation should never occur to begin with.

 

[Vengified]

So, will a MASSIVE water change cause me issues with the pH dropping from tannins? If I changed 75% of it right now, I'm guessing the pH would hop up 0.4-0.5 when I did it, as it has dropped that much over the past week.

Out of curiosity, if micro-organisms always develop, and need to be removed from the system, regardless of filtration or plants, does that mean the Walstad method is actually ineffective? I dont doubt you guys at all, I am no expert, and have just read about Walstad method of using plants as filtration with little to no water changes.

The same goes for Aquaponics. I have seen videos and articles on using clay beads, water pumps, etc, and flowing water into a garden of plants above the aquarium, where all the harmful chemicals/organisms are consumed by plants, and then clean water pumped back into the aquarium. Those people claim they havent done water changes in a year or more, and the plants take care of everything?

Again, I dont disagree, and I'm not trying to get out of water changes. I enjoy it actually, and usually feel the need to move something, or fix something in the tank anyways, and it's easier with the tank half empty. But I am curious how people claim they dont change water, with thriving fish, no filters, just plants? Is it all hogwash? Or are their fish just barely surviving, but they assume they are well off?

 

[Byron]

So, will a MASSIVE water change cause me issues with the pH dropping from tannins? If I changed 75% of it right now, I'm guessing the pH would hop up 0.4-0.5 when I did it, as it has dropped that much over the past week.

The pH is part of the GH and KH trio. It is natural for the water in an aquarium with fish to become acidic primarily from the breakdown of organics, and as the CO2 produces carbonic acid, the pH lowers. But this process is bound by the GH and KH, especially the latter (carbonate hardness or Alkalinity) which acts to "buffer" the pH, preventing changes. But the effectiveness of this is dependent upon the buffering capability of the KH; a low KH will have less than a higher KH. So it would help to know your GH and KH of the source water.

As for the pH rising after a water change, this might or might not occur, depending upon the GH and KH. Once an aquarium is established, the biological system tends to be stable. If we impact this minimally, meaning, we are not adding chemicals/substances that target the natural processes, it will stabilize and resist significant changes. The GH, KH and pH of the fresh water are still factors.

Out of curiosity, if micro-organisms always develop, and need to be removed from the system, regardless of filtration or plants, does that mean the Walstad method is actually ineffective? I dont doubt you guys at all, I am no expert, and have just read about Walstad method of using plants as filtration with little to no water changes.

I am very familiar with this method; I have read Diana's book, several articles, and belong to her forum. She will readily tell you that this will work but only with a moderate or minimal fish load. Increasing the fish load requires some water changes. Most of us keep way more fish in a given aquarium than she does, believe me. And you need a very good growth of plants, and some fast-growing species.

The same goes for Aquaponics. I have seen videos and articles on using clay beads, water pumps, etc, and flowing water into a garden of plants above the aquarium, where all the harmful chemicals/organisms are consumed by plants, and then clean water pumped back into the aquarium. Those people claim they havent done water changes in a year or more, and the plants take care of everything?

I have no direct experience with this method (there are some members here who have, they may be able to explain further), but I believe this is a similar idea only occurring outside the water. Plants with what is termed the aerial advantage are more rapid assimilators of nutrients and substances in the water. This is because the uptake of CO2 (carbon) via the leaves from the air is about four times faster than it is submersed. [This also explains the significant benefit of floating plants, which is why I am so often recommending them.] You do want to ensure the plants are not toxic; some, like Philodendron, are highly toxic to fish. I don't know what if any limit there may be to this method, but those with experience can tell us.

Again, I dont disagree, and I'm not trying to get out of water changes. I enjoy it actually, and usually feel the need to move something, or fix something in the tank anyways, and it's easier with the tank half empty. But I am curious how people claim they dont change water, with thriving fish, no filters, just plants? Is it all hogwash? Or are their fish just barely surviving, but they assume they are well off?

I suspect your last sentence is close. Again, it depends upon the fish load to water volume, live plants, feeding and foods fed, etc. I recall once reading that a 55 gallon planted aquarium could handle itself with six tetras as the only fish load, without water changes or filters. That is a pretty high ratio.

Aquarists should aim to have fish thrive, rather than survive. Many certainly do not know how to recognize the difference. Life span is often a clue, spawning not always so. Interactive behaviours can be. An obvious example...a Betta can live for years in one of those glass bowls, but does that mean it is thriving? I doubt it.

My tanks are all planted, using the low-tech or natural method. I do add some fertilizer, primarily substrate tabs for the larger plants, and a liquid comprehensive but less than recommended because I do not like adding anything to the water unless essential. I do the 65-70% water change every week, and have done for years now. I have fish that live long past their normal expected life-spans, and most of them regularly spawn (I see fry now and then, from eggs that don't get eaten!). My male Bolivian Ram, a somewhat delicate species, was well into his ninth year when he died, which is pretty good for a species with a 4-5 year life expectancy. My Whiptail (Rineloricaria parva) is now in his tenth year, and I understand the norm for this species is 5 to 8. I have been in this hobby for over 25 years now, and one does learn to recognize some things; the benefit of substantial water changes on the fish each week is quite noticeable.

 

[seangee]

Many years ago I decided to create a "self sustaining eco system" in a 450l tank. I knew nothing of the Walstad method. I did use CO2 injection and high lighting to kick start the jungle. I later switched to regular lighting without CO2 because I was spending all my time trimming plants and I was after zero intervention.

Was it successful? Well in 4 years I never touched the tank other than topping up water - not even food. At the end of the 4 years I had more fish than I started with, they appeared to be normal size and no visible algae. The tank was on display in the dining room and my wife would not have tolerated it if it looked bad. About 10 years ago I converted it to a regular tank. This was because I had to move it to decorate the room. Draining it was a terrifying prospect because it had a deep sand bed and knew that disturbing it would mean instant death of the tank. I moved the fish into a smaller temporary tank and restarted the big one from scratch.

I finally shut that tank down 3 years ago. Another re-decoration and I decided I am no longer able to manage a tank that size. Also the wooden stand was rotting and would not survive being moved. I gave away my clown loach as I did not have anything big enough to accomodate them. These are notoriously bad at coping with poor water quality and were in my "natural" tank. The first fish I introduced to the tank were 4 bristlenose fry. When I was rehoming fish I kept the biggest BN and he is still enjoying life in my 55G - he is about 15 now.

I can't answer the survival vs thriving question. Its not something I will ever do again and its not something I would recommend - but yes it is possible

 

[Vengified]

Thank you BOTH @Byron and @seangee Both of you provide a WEALTH of information! As stated, I dont mind the W/C, and wasnt trying to avoid it, and honestly just wanted to know why we do them, if nitrates are negligible, tank is cleaned, and fish/shrimp thrive, which everyone has given good reasons why! I do appreciate the feedback! I'm just happy to see with all the plants, and the reduced feeding, my nitrates are nowhere NEAR the 40ppm they were hitting after 2 days! Hornwort and Frogbit I believe are a huge asset in this as well.

So it would help to know your GH and KH of the source water.

My source water is the tap. Not sure if you are familiar with Montana, USA, but I live a half hour from Glacier-Waterton International Peace Park, which spans between USA and Canada, and the name certainly fits. The peaks have snow 365 days, year round, and the runoff feeds many lakes/rivers, which ultimately feed our tap. In the rocky mountains, which also rings true, our water is EXTREMELY hard! I dont know the GH/KH, only TDS, and I know that is always off the charts, 300+ and even after a few days (which is the longest I went between water changes til this last week), it's still above 300. I know my water can buffer pH fluctuation very well, but I did put a piece of cholla about 4 inches around, 30 inches long, (the bottom 6 inches is a root, about 10 inches around), and I had no way to boil it, so it is leaching a LOT of tannins for a 20g. Literally spans the entire tank, as you can see.

She will readily tell you that this will work but only with a moderate or minimal fish load

The big part of what intrigues me about this, is not necessarily fish, but shrimp. I think the only way I would try any sort of natural tank, would be with shrimp. But I imagined if I did, I would start a somewhat normal tank with a few fish, get plants going, then remove fish, add shrimp, and eventually remove filter somehow. I guessed I would have to leave filter media in the tank for a bit, but I dont know. It wasnt a plan, just a "maybe someday" thought. I dont plan on ever having fish in stagnant water so to speak.

But again, to all you who have given me input:


... now I'm gonna go do my first water change in 8 days, and the first water change I've done, that wasnt only 3 days after the previous! I'm so proud I dont have a gross, high nitrate tank!

 

[Colin_T]

Yes a big water change can change the pH a bit but is unlikely to affect the fish. It is a bit like rain coming into a pond and topping the pond up. The pH changes and so does the CO2 and O2 in the water. I wouldn't worry too much about the pH.

If you have concerns either add a KH buffer to the tank or add a small piece of limestone or some shells to help buffer the KH and stop the pH dropping due to the wood.

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Byron pretty much covered the Walstad method. This can work to some degree assuming there are only a few fish in the tank, the fish are free of disease organisms before they are added to the tank, and assuming no disease organisms get into the water from nearby tanks. But the water chemistry does still change over time unless you add buffers and use Activated Carbon from time to time to remove some of the chemicals in the water.

Water changes reduce the need for you to add buffers or try to filter out chemicals with Activated Carbon.

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Permaculture is basically having a pond or aquarium with fish or crustaceans living in it. Water is pumped from the fish pond/ tank onto a hydroponic setup (plants growing in some sort of media that is not soil based). The plants use the nutrients in the water and the "clean" water is returned to the pond. People eat the fish/ crustaceans and plants. It is meant to resemble a natural cycle of life with fish food and waste feeding the plants, and the plants cleaning the water.

In a permaculture set up, the fish are usually killed within 6-12 months and eaten and are not always in the best health when this happens, certainly when compared to healthy wild caught fish of the same species. Most are in reasonable condition but their overall health is not as much an issue because the fish or crustacean is going to be cooked and eaten. Again permaculture ponds become soups of microscopic organisms and the fish are usually covered in these tiny creatures.

The plants in permaculture set ups are usually lacking trace elements and many people find they need to add some sort of liquid fertiliser to help the plants reach their full potential.

To get the most out of a permaculture setup, you need to have a lot of fish and put a lot of food into the pond, and use plants that like wet feet. That is plants that don't mind having wet roots.

Research has shown that fish/ crustaceans grown in permaculture set ups grow faster and have a higher yield when the ponds are wiped/ scrubbed out and given big water changes, compared to ponds that are topped up and left dirty. The plants also do better with the big water changes because it dilutes the nutrients that have not been used and brings the water back into balance. The water changes only need to be done once a month for this change to be seen, but water changes done more frequently (weekly or fortnightly) showed improved growth over the monthly water changes.

Even pure Hydroponic set ups (not permaculture based) change their water/ nutrients each week because it helps the plants and produces better results.

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One of the main issues with keeping fish in a small body of water is the fish are confined to a small area. If there are any disease organisms in this water, the fish will become infected by the organisms. Fish can carry protozoan, spirozoans, bacteria, viruses, fungus, flukes, worms and other micro-organisms in and on their body, and these can live on the fish for a long time before they appear as a disease. The micro-organisms build up in numbers and the water becomes a virtual soup of microscopic life waiting to infect the fish.

In the wild if fish are in ponds that are separated from a river, they might spend 3-6 months in a stagnant pond. Sometimes these ponds have plants in and other times they don't. The fish in the ponds are sometimes eaten by predators or die when the water evaporates. Assuming the fish don't get eaten or dry out, they will remain here for 3-6 months before the rains come and wash all the nutrients away and the fish can swim out into the river again. In the river during the wet season, the fish to water ratio is huge, less than 1 inch of fish per 1000+litres (250 gallons) of water. That's like 1 neon tetra in a 10x2x2ft tank.

So even if the fish are trapped in a pond during the dry season, it is only for a short period of time before they end up back in the main river. In the river there is a lot more water for each fish and the water is usually flowing downstream. Any disease organisms in the water or on the fish, eventually wash downstream away from the fish. And due to the volume of water, the fish are significantly less likely to be exposed to disease organisms to begin with. This doesn't mean wild caught fish don't catch diseases, just they are much less likely to catch something in a river due to the water volume and constant clean water flowing past them.

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Having lots of plants in a tank so the nitrates are kept very low is good, but carbonic acid and other chemicals (mentioned by Byron) that are produced by the fish, and disease organisms, can build up over time and cause problems. Big regular water changes dilute these organisms and keep the environment cleaner with fewer harmful pathogens in the water that could affect the fish. The water changes also help dilute chemicals and replace minerals the fish need or that are required to stabilise pH.

Whilst the Walstad method can be used, it is not the norm because it requires disease free fish and only a few fish in a big tank. This is different to what most people want, with a community tank that holds lots of fish with lots of different colour.

Permaculture can also be used successfully and has been for a very long time. But it is a way of farming something to eat, rather than keeping a species alive for as long as possible. Most hobbyists want their fish to live as long as possible and don't want to eat them after 12 months.

The majority of people that don't do water changes, eventually lose most if not all the fish in the tank or pond. Many people top these aquariums or ponds up so are still using water. If they were to remove some water before topping the tank up, the fish would be better for it.

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Vengified, in your guppy tank you had a heap of fish (baby guppies) and were adding a bit of food to encourage good growth. You did regular water changes and gravel cleans and this is what you do to grow fish, (lots of food and big regular water changes). You did everything right and yet your Otocinclus still developed a protozoan infection. If that can happen in your tank with all the water changes and gravel cleans you were doing, imagine what would happen if you did no water changes or gravel cleaning.

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My final point on water changes. Imagine living in your house. You can't go outside, can't open a window or door and there is no real ventilation in the house. You have no plumbing and only food, water and a few plants. You would quite literally end up living in your own filth/ waste. This is what happens to fish in an aquarium. They literally live in their own waste. Filters remove the larger particles from the water but the micro-organisms found in the fish poop and the ones growing in the water eventually make the fish sick. Big water changes, gravel cleaning and filter maintenance all help keep the tank cleaner by removing this gunk, making it healthier for the fish.

 

[seangee]

To the original question
Most people on this thread recommend 50% or more every week. Others recommend 10-30% every week - or more frequently. Not going to debate the merits of either approach but there is one thing that is clear:

Those that do weekly water changes are not responsible for many (if any) of the "help my fish are sick / dying" threads on this or other forums.

Personally I question how many that claim to do a monthly change actually do so every month. For me the routine makes it easy, and like you I do actually enjoy it. It also gives me a good safety buffer. I am going on holiday next week. I'm currently in the middle of my usual 60% weekly change. I know that it will be 3 weeks before the next change but I am confident that I don't need to do anything special before or after the holiday.

 

[Vengified]

Wow @Colin_T yet again your an encyclopedia! And yet again, putting it in simple terms as well, brings it into perspective on a relatable analogy: I certainly would NOT want to live in my own waste either, but as you know, I was changing water daily, every 2 days, every 3 days, and then just this weekend, did my first water change where I went a whole week between!

Those that do weekly water changes are not responsible for many (if any) of the "help my fish are sick / dying" threads on this or other forums.

I just have to argue this a little bit, as I have never gone even a week, until just recently, between water changes, on two different tanks, and my oto still got sick. Granted they are sensitive, but I've had 3 for 6 months all doing well, and then one randomly got an infection (most likely a new gourami brought it in), but the point is I didnt neglect my responsibility to my finned friends, and one got ill. I know I'm no an expert, or even very knowledgeable or tenured in fish keeping, but I do take all suggestions seriously, and do as instructed, to keep my fish happy and healthy. I even took flack from the wife, for buying bigger tanks twice, and then buying an additional tank, with the excuse of needing a nursery/QT/hospital tank, and THEN getting another small tank, to treat a sick old guppy. Got serious wife aggro, all stemming from us getting a 3gallon for the kid, and @Colin_T telling me I needed a bigger tank, so I do listen and try to provide the best possible life for our fish.

I am NOT angry, or offended @seangee so, if it comes off that way, I apologize. I'm perfectly content and calm, I just wanted to make it clear, that even in the best of conditions (like @Colin_T stated) fish can get sick, and some of us new fishkeeper, will ask for help, not knowing why our fish is sick, when we are doing everything correctly within our power, to keep them healthy.

Thank you ALL for the loads of info, and the explanations! I knew some of the reasons for water changes, but didn't know them all by any means. Sort of felt like I was blindly doing as I was told, and wanted to know the science/reasons behind it. Especially since my 5 year old is at the "WHY" stage, and asks me "Why?" For EVERYTHING! Just thinking about the fact, we having another one in 3 months, is driving me crazy with dread!

Just wanted to add, with all the reasons listed for water changes, it makes more sense cost/time wise, to just do them, (as I always have done, and intended to anyways), as opposed to testing, adding buffers, fertilizers, special plants, minerals, etc. Honestly, if anyone ever stumbles upon this thread, it will just be easier and faster to change water weekly, than spend gobs of money on additional products (which you wouldn't find in a natural environment anyways), and gobs of time figuring out what to add and when.

... I am happy with my water changes! Gives me a chance to interact with the fish somewhat anyways. *Dont worry, I'm not grabbing them or anything, but some do come up and peck at my arm to see what's up.

 

[Colin_T]

Got serious wife aggro, all stemming from us getting a 3gallon for the kid, and @Colin_T telling me I needed a bigger tank, so I do listen and try to provide the best possible life for our fish.

Hang on a minute, I don't recall telling you to get a bigger tank. Or did I.

Don't blame your MTS on me

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You do realise when your daughter is born, you will have to get her an aquarium too. Can't have one kid with a tank the other without. It will be a good excuse to make your MTS worse