General water change rules?

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Kypeli

Aquarium Advice Apprentice
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Oct 16, 2010
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Turku, Finland
This is my first message on this forum, but it would probably also be the first question I ask from a fellow aquarium hobbyist.

How should I change my water?

I've heard probably as many advice about this as there are people giving them. Really. Some say that a small amount (10-15%) of water should be changed weekly while others say that 20-30% monthly or otherwise you will ruin the ecosystem. There quite a big gap there. Any opinions?

A second thing would be gravel vacuuming. In general I've heard that every time you change water, you should also vacuum the gravel (as good as you can). But I've also heard that this (too) will ruin the ecosystem, so you should gravel vacuum only 1-2 times a month.

I have a new Juwel RIO 180 liters tank (46gl) so this is what I do: change 10-15% of the water every other week with only light gravel vacuum, and then once a month change 30% of the water with thorough gravel vacuuming. By this I hope I can keep the nitrite levels down, but at the same time not disturb the ecosystem too much.

What do you think?
 
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If your tank is recently set up then you don't want to vacuum the gravel yet. The beneficial bacteria that you are trying to build during the cycle live on the gravel/substrate, decor, etc. By vacuuming the gravel, you're removing the bacteria before it has a chance to completely colonize.

If your tank is a recent set up and you have fish (doing a fish cycle) then you will need to do water changes to keep ammonia and nitrItes down. Anything over .25 for ammonia is toxic to fish and larger water changes would be needed.


Now, if your tank has finished the cycle, regular water changes are a must along with a gravel vacuuming. Here's what I do, but everyone has their own way.

I use a python water system, those things rock for working on multiple tanks, which we have. If you have the one tank, you can get away with buckets, though the python would still be easier.

Anyways,

I do a 50% - 90% change for our larger tanks, depending on what type of fish are in the tank. While I'm removing water, I clean the gravel/sand as best I can. Moving decor if possible (2 of our tanks are too tall for me to move some things) Also depending on which tank, I'll do this once a week our once every other week. Example: our cichlid tanks get cleaned once a week because they are big bio-load producers (big poopers) our tetra/ angelfish tank gets cleaned every other week. More fish but the still don't put out as much waste as the cichlids.

On our smaller tanks, it again depends on whats in them.

Our shrimp only tank gets cleaned every 3rd week. It's a 10g but only has red cherry shrimp and a hillstream loach. Almost no poo in there. Our tank of feeder guppies gets cleaned once a week. Guppies poo a lot.

So, I drain and vac the gravel, move around any decor I can to clean underneath, replant or replace decor, clean my filters, scrub the algae off the glass and decor (while the water is draining) If I have airstones that need changing out I do that while the water level is low, just general maintenance stuff.

For filling, I dose with Prime for the tank volume, so if I'm doing the 29g, I dose for 30g (not like there's a difference ya'know) and fill directly from the sink with the python.

If I do buckets, I use prime for the volume of the buckets. Luckily I only do this method if it's for a QT tank so as not to stress the sick fish too much.
 
It is a complete myth, clean water can do nothing but good for your tank. It is all about frequent massive water changes. 50% or more once a week at least. It's just a matter of how much Prime you can afford ;)
 
Welcome to AA! :)

I agree with the above and try to always keep in mind the natural water volumes and turnovers that the fish we keep evolved in. It's hard to replicate the turnover capacity of creeks, rivers, lakes, puddles, etc. so the next best thing is frequent export of wastes and chemicals through a water change.
 
If your tank is a recent set up and you have fish (doing a fish cycle) then you will need to do water changes to keep ammonia and nitrItes down. Anything over .25 for ammonia is toxic to fish and larger water changes would be needed.

I don't have an ammonia test, but I have tested my NO2 and NO3. NO2 shows 0.05 and NO3 10. Pretty normal AFAIK.

I do a 50% - 90% change for our larger tanks, depending on what type of fish are in the tank.

How often do you do this? Under what conditions do you change up to 90% of the water? This sounds pretty much to me.

But I guess as long as the NO2 is not rising, there is little need to change 50% of the water, right?

So, I drain and vac the gravel, move around any decor I can to clean underneath, replant or replace decor, clean my filters, scrub the algae off the glass and decor (while the water is draining)

Yeah, so pretty much the same I am used to do. That is, clean the gravel as well as I can. No need to worry about loss of the good bacteria once the N-cycle is complete.

For filling, I dose with Prime for the tank volume, so if I'm doing the 29g, I dose for 30g (not like there's a difference ya'know) and fill directly from the sink with the python.

Still using just buckets ;) With only one tank, I guess that is bearable. And it's part of the fun in some weird way too I guess.
 
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It is a complete myth, clean water can do nothing but good for your tank. It is all about frequent massive water changes. 50% or more once a week at least. It's just a matter of how much Prime you can afford ;)

So you mean I cannot change my water often enough (after the N-cycle is complete, I guess)? Hmm - this is so confusing since I hear the opposite too from different sources.

I use Tetra AquaSafe but I guess that's the same thing as Prime. It's not that expensive compared to other expenses with the tank so I don't mind buying that even too often ;)
 
Welcome to AA! :)

Thank you very much! :)

I agree with the above and try to always keep in mind the natural water volumes and turnovers that the fish we keep evolved in. It's hard to replicate the turnover capacity of creeks, rivers, lakes, puddles, etc. so the next best thing is frequent export of wastes and chemicals through a water change.

That makes sense indeed. So you think my water change plan not frequent enough? But again, I guess it also depends on the tank in question. I mean, larger tanks in general require less frequent water change - but depending on the amount of fish in them. I've heard that Juwel's Bioflow filter (which I have) would be an excellent filtering system and that would also reduces the need for too frequent water change.

I've had the tank for only 2 months now, so I will need to follow the NO2 and NO3 readings.
 
As already mentioned, clean water is the key to successful fishkeeping. Nitrite levels should be at 0, and nitrate levels should be kept as low as you are willing to. 40ppm is the accepted high limit for nitrates, most aquarists will try to stay below 20, and many of us like to keep it below 10. Test kits will help you determine what the minimum amount and frequency should be. changing more than the minimum will in no way harm your tank or disrupt the N cycle. What it will do is give you some insurance for those times when you have to miss a change. Also, as your fish grow, the minimum requirement will change. Regardless, clean water will keep you from experiencing many of the problems that cause people to leave the hobby. much of what you describe in the first part of your post about amounts and frequencies of water changes are pieces of bad advice being repeated by the misinformed because they read it and accepted it as true.
 
Changing more than the minimum will in no way harm your tank or disrupt the N cycle.

I am maybe embarrassed to say this, but this is new to me :) Thanks. It of course all makes sense, and I guess I (among others it seems) are just afraid to disrupt the N cycle.

I actually like to do the water change so I don't mind changing it every week. This thread gives me confidence that I should do that.

much of what you describe in the first part of your post about amounts and frequencies of water changes are pieces of bad advice being repeated by the misinformed because they read it and accepted it as true.

Yes, this is indeed interesting and confusing to me. Only by doing you learn of course.

But what I read in a beginners guide to freshwater aquarium -book was that I should change 10-15% water weekly with only light gravel vac and 30% monthly with normal gravel vac. When I talked about this with my local aquarium store keeper (it's not a general pet store even :)), she said that weekly changes are too frequent or not needed. I guess, hence my careful approach to water change frequencies.
 
You will not be disrupting the nitrogen cycle by changing water. Gravel vacuuming too frequently can pose a bit of a threat, but mainly all of your beneficial bacteria is in the filter media, changing that is what is going to cause an ammonia/nitrite spike. Water changes will not harm your filter.

Pet Shops will tell the customer anything they can to sell more products such as Ammonia blocking products and some bologna called "De-Nitrate", and most of this stuff doesn't work. Telling a customer to do frequent FREE water changes would be a massive blow to their profits. I know this because I worked at a pet shop... I got in lots of trouble for giving the advice I learned here, because it kept customers from buying garbage products like "Am-Lock." And "Purigen"...

Always remember that, and remember that fresh clean water from frequent water changes can solve almost every aquarium problem.
 
I appreciate your advice and the honesty! :) Yes, I've never bought any De-nitrate or Am-locks - if you need them, you are already in trouble with the tank.

I'll just go and change some water now. Been a week since last time.
 
Good to hear! And you'll notice the fish will appear more relaxed after the water change as well, which is my favorite part of water changes ;)
 
I do a 50% - 90% change for our larger tanks, depending on what type of fish are in the tank.


How often do you do this? Under what conditions do you change up to 90% of the water? This sounds pretty much to me.

It depends on the tank as was stated in the rest of that paragraph. If it's our cichlid tanks, then once a week, if it's the tetra/angelfish, every other week. It's all about the bio-load (how much poo the fish put out) While there are more tetras and angelfish than there are cichlids, the tetra/angelfish still have less of a mess than the cichlids.
 
So much different information out there because every tank is different and what is good for one tank is not always good for another. as DragonFish said it mostly has to do with the bioload of the tank not only with fish but if you have live plants that changes things too. unless the fish has naturally evolved into the ability to live in a puddle where the water never changes then water changes become necessary. you could do water changes every day if you want to and it would probably not hurt anything as long as the temp and ph dont swing much. i think the question then becomes how long can the tank go without a water change and not hurt the tank? which goes back to bio load. the lower the bio load the longer you can get away with not doing a water change. the more often the water change the healthier the fish will be in my opinion as well as the plants if you have them. i try to do about 25% every weekend and i still use buckets too. if you treat the water in the bucket it is less volume and the water conditioner goes further.
 
So much different information out there because every tank is different and what is good for one tank is not always good for another. as DragonFish said it mostly has to do with the bioload of the tank not only with fish but if you have live plants that changes things too. unless the fish has naturally evolved into the ability to live in a puddle where the water never changes then water changes become necessary. you could do water changes every day if you want to and it would probably not hurt anything as long as the temp and ph dont swing much. i think the question then becomes how long can the tank go without a water change and not hurt the tank? which goes back to bio load. the lower the bio load the longer you can get away with not doing a water change. the more often the water change the healthier the fish will be in my opinion as well as the plants if you have them. i try to do about 25% every weekend and i still use buckets too. if you treat the water in the bucket it is less volume and the water conditioner goes further.

I agree 99%, but there are compounds and chemicals that are also removed from the water (pheromones and the like) through water changes. Those can affect behavior, breeding, stress level, etc. and are more important than we give them credit for.

No fish has evolved to live in a mud puddle. They've evolved to survive relatively short periods spent in a mud puddle. Though evolution has very little to do with the bettas (most common example of puddle fish) that are in the hobby now. They are a myriad of different hybrids at this point and shouldn't probably be considered splendens anymore. Sorry for the random rant... :cool:
 
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