Seems there are a lot of opinions on how often to change the water in your tank. We have several in the house. I have a 30 gal in my office and hubby has a 40 gal in the living room. I change out some of my water weekly - usually about 10 gals. He prefers to wait a little longer in between. What is the consensus here on how often to change the water?
How often to change water
- Thread starter macmom6
- Start date
The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Bigfoot1030
Aquarium Advice Regular
20%-25% every week sometimes a little longer.
cbwmn
Aquarium Advice Freak
I have hybrid black angels. For the first nine mos, 50% every day.
Same for discus, both kind need very clean water.
My angels are a year old now and I do 50% 3 X a week.
My other tanks have not so sensative fish so 50$ once a week.
Charels
Same for discus, both kind need very clean water.
My angels are a year old now and I do 50% 3 X a week.
My other tanks have not so sensative fish so 50$ once a week.
Charels
I change about 30% at least once a week. If one of the fish isn't acting right I do another change and the following day another smaller change. I have rather low stocked tanks if I had more fish there would be bigger PWC. If there is an unexplained death another 40 to 50%.
darkmule27
Aquarium Advice Activist
Somewhere around 50% once a week. Basically whatever 2 kitty litter tubs' worth is out of the 20G, haha.
new2betas
Aquarium Advice Addict
I agree with most all comments already made...IMHO you can't do too many water changes. So, as many as you want to do is fine. At least 50% weekly I would say, if you don't want to do more. I have a very informative aquarium book I bought when I first got back into the hobby and the guy that wrote the book is always stressing water changes, water changes, water changes...they pretty much will take care of a lot of issues that arise.
jsoong
Aquarium Advice Addict
You can do less with a heavily planted tank, but otherwise 25-50% weekly is good ... more if you are heavily stocked or have sensitive/messy fish. One way to gauge is to watch the nitrate level. In a non-planted tank, doing enough pwc to keep nitrates less than 5 or 10 is a good rule of thumb.
Pacei
Aquarium Advice Apprentice
- Joined
- Mar 27, 2009
- Messages
- 22
I do 30% weekly. If I feel a tank is overstocked, then I do more. Even on a lightly stocked tank with plants, I try to keep at least 20% weekly.
HooKooDooKu
Aquarium Advice FINatic
Well, there's how often the water NEEDS changing and how often it GETS changed.
I would hazard the guess that either 10% weekly to 25% semi-monthly is what is most commonly recomended.
But the real answer is how often is it NEEDED, and for that, it depends upon the bio-load, how much you feed, and if it's a planted tank.
One way to determine NEED would be to get a Nitrate test kit and do some experimenting with your tank. As a rough guideline, I would start by measuring the amount of Nitrate in the water, and then do what ever amount of water change was needed to get nitrate down to 10ppm. Then measure nitrate daily and see how long it takes to reach 20ppm. You can then determine that to keep nitrates in the 10 to 20ppm range, you have to do the equivilent of a 50% water change during that period. So if it takes a month to go from 10 to 20ppm, then you need to do something like a 25% PWC every other week.
Actually, the better advice would likely be to do PWC twice as often as the numbers suggest. So if your testing indicates you need to do 50% water changes per month, perhaps you should do 25% PWC on a week.
Lower bio-loads and planted tanks will take longer to get nitrates to double from 10 to 20ppm.
I would hazard the guess that either 10% weekly to 25% semi-monthly is what is most commonly recomended.
But the real answer is how often is it NEEDED, and for that, it depends upon the bio-load, how much you feed, and if it's a planted tank.
One way to determine NEED would be to get a Nitrate test kit and do some experimenting with your tank. As a rough guideline, I would start by measuring the amount of Nitrate in the water, and then do what ever amount of water change was needed to get nitrate down to 10ppm. Then measure nitrate daily and see how long it takes to reach 20ppm. You can then determine that to keep nitrates in the 10 to 20ppm range, you have to do the equivilent of a 50% water change during that period. So if it takes a month to go from 10 to 20ppm, then you need to do something like a 25% PWC every other week.
Actually, the better advice would likely be to do PWC twice as often as the numbers suggest. So if your testing indicates you need to do 50% water changes per month, perhaps you should do 25% PWC on a week.
Lower bio-loads and planted tanks will take longer to get nitrates to double from 10 to 20ppm.
hookoodooku has done an excellent job on explaining how often PWC NEEDS to be performed and this lead me to another question...
is it possible to create an aquarium that does not need pwc?
like say 200 gallon tank heavily planted and really really low stocked tank?
all the energy the fish get derived from sunlight? (sunlight -> algae -> fish)
is it possible to create an aquarium that does not need pwc?
like say 200 gallon tank heavily planted and really really low stocked tank?
all the energy the fish get derived from sunlight? (sunlight -> algae -> fish)
HooKooDooKu
Aquarium Advice FINatic
In theory, only if you can find the right combination of plants that will absorb ALLl waste products generated by the fish, and fish that can get the needed balanced diet from feeding on only the plants.
In other words, if you can set the tank up as a closed system (think Biosphere 2 http://en.wikipedia.org/wiki/Biosphere_2) you could avoid PWC. But as you can see if you either know about or read about Biosphere 2, a closed system can be more difficult to maintain than an open one where you do PWC.
I think the most likely result would be that for a long while, everything would go ok, but unseen to you, conditions would slowly deteriate. But at first, the fish would slowly adapt to the slow deteriation, until finally, you suddenly start losing fish as the lack of maintainence eventually leads to unhealthy fish and they eventually die.
[Time to embarass myself]
As a teenager, not knowing what I was doing and not knowing anything about fish, accidently did an experiment. I had a gold fish in a 5 gallon tank. There was no heater, no light (except what came through the bedroom window), no filter, and not even a substrait in this tank. Initially, changed the water when it got to looking dirty and I feed him once in a while. But as time went on, the periods between feeding and water changes got longer and longer until finally they both just stopped. Eventually, the ONLY maintainence and care this fish was given was to add water to the tank to replace what was evaporating (and even that came from the catch basin from the dehumidifier in the next room I was responsible for emptying). So eventually, this goldfish became an alage eater (must have, because I wasn't feeding him), and his waste must have been getting converted back to alage. This poor fish survived under these conditions for over two years. Then suddenly one day, this fish (that can live for more than 20 years when properly cared for) died at an age of about 3 to 4 year old. The point being, I setup a basically closed system, it kept the fish alive, but unknown to me, the conditions were harming the fish and eventually lead to his premature death.
BTW, yes it was horrible what I put that fish through. But now I know better. Today I once again have a goldfish (actually it belongs to by son, but given his age, I'm the one that has to care for it). This time, the goldfish lives in a 20 gallon tank with 3 rosey red minnows, snails, and shrimp as tank mates. The tank has a filter, air stones, a thick sand substrait, and several plants. The tank is well lit, the fish are feed twice a day, occationally with peas to aid their digestion, and gets 10%-20% weekly PWC. In four months, the goldfish has grown to twice the size that other goldfish ever became after 3 to 4 years.
In other words, if you can set the tank up as a closed system (think Biosphere 2 http://en.wikipedia.org/wiki/Biosphere_2) you could avoid PWC. But as you can see if you either know about or read about Biosphere 2, a closed system can be more difficult to maintain than an open one where you do PWC.
I think the most likely result would be that for a long while, everything would go ok, but unseen to you, conditions would slowly deteriate. But at first, the fish would slowly adapt to the slow deteriation, until finally, you suddenly start losing fish as the lack of maintainence eventually leads to unhealthy fish and they eventually die.
[Time to embarass myself]
As a teenager, not knowing what I was doing and not knowing anything about fish, accidently did an experiment. I had a gold fish in a 5 gallon tank. There was no heater, no light (except what came through the bedroom window), no filter, and not even a substrait in this tank. Initially, changed the water when it got to looking dirty and I feed him once in a while. But as time went on, the periods between feeding and water changes got longer and longer until finally they both just stopped. Eventually, the ONLY maintainence and care this fish was given was to add water to the tank to replace what was evaporating (and even that came from the catch basin from the dehumidifier in the next room I was responsible for emptying). So eventually, this goldfish became an alage eater (must have, because I wasn't feeding him), and his waste must have been getting converted back to alage. This poor fish survived under these conditions for over two years. Then suddenly one day, this fish (that can live for more than 20 years when properly cared for) died at an age of about 3 to 4 year old. The point being, I setup a basically closed system, it kept the fish alive, but unknown to me, the conditions were harming the fish and eventually lead to his premature death.
BTW, yes it was horrible what I put that fish through. But now I know better. Today I once again have a goldfish (actually it belongs to by son, but given his age, I'm the one that has to care for it). This time, the goldfish lives in a 20 gallon tank with 3 rosey red minnows, snails, and shrimp as tank mates. The tank has a filter, air stones, a thick sand substrait, and several plants. The tank is well lit, the fish are feed twice a day, occationally with peas to aid their digestion, and gets 10%-20% weekly PWC. In four months, the goldfish has grown to twice the size that other goldfish ever became after 3 to 4 years.
Same here, 20-30% weekly unless the tank has a lot of fish in it then i change more.
Similar threads
Latest posts
-
-
-
-
Nitrates up, pH and total alkalinity down
- Latest: Airborne 82nd
-
-
