Water changes

[Jimmy120883]

How often do people do water changes?
How much do people change?
Ive seen everything from 10% 25% 50%.
I have several tanks and all are fine however I've just got my daughter a small 40l tank with guppies in and at first everything was fine they were breeding and the fry were thriving.
5 months later guppies are dying weekly and I don't know what the problem is.
I do weekly water changes of 10% is that too much? Too little?

 

[Uberhoust]

I have had good luck with 50 to 70% weekly to bi weekly water changes on my tanks where I can use un-adjusted water. In my shrimp tank I do 25% weekly but I push the GH up to 150 to 180 ppm on that tank. I mostly keep angelfish and my water has very low KH 10 ppm and GH 0 by test kit. The angel tanks are 37 and 75 gallon, the shrimp tank is 20 gallon.

 

[sharkweek178]

10% isn't enough. Personally, I do weekly changes of 50-60%.

 

[Naughts]

I do 50% weekly, if I'm delayed in doing a w/c for 2 or 3 days I will do as much as 75-80%. I use a hose to drain and refill the tanks so it's no problem.
My daughter has a 40l with a pair of apistos and she does 25% weekly. That's small but it's easier as the tank is upstairs and uses rainwater that I collect outside.

 

[Sanityassassin]

It depends on your bio load on your tank. All tanks are different. Just because someone does "X" amount of gallons every week on their tank, doesn't automatically mean that that is the right level for you. Far from it.

It's all about monitoring your nitrate and doing your water changes when it reaches a certain level of acceptability. And bear in mind that each hobbyist has their own ideas of what level of nitrate is acceptable. But generally speaking I think most of us would go along with 20ppm as a max.

So, when your nitrate reaches 20ppm, do a water change. 50% w/c will reduce nitrate to 10ppm, 75% w/c will reduce nitrate to 5ppm, and so on and so forth, simple maths.

Then you need to measure how long it takes go get up to 20ppm again, and repeat your w/c schedule, and so it continues. Over a period of time you will get into a routine, and you will know exactly when to change your water, and how much.

Feeding heavily and overstocking can increase nitrate creep meaning you need to perform more frequent and/or bigger water changes.

 

[Magnum Man]

I agree, depends on bio load to some extent... I usually do 3 - 5 gallon buckets per week, or every two, if I'm too busy... I use a 6 gallon bucket, so I actually get 5 gallons of water in it... most of my tanks are big ( all that are set up right now ) & water changes will be in buckets full ( no half or 1/4 buckets ) so the percentage changes a little by size of the tank...

for example on my 45 gallon aquarium, 2 buckets would be a 22% water change... 3 buckets is a 33% water change... on my 55 gallon tanks ( I have 4 set up right now ), 3 buckets is a 27% water change... so I'm "averaging" about a 30% water change every time...

also take into account, your gravel & toys displace water... so your tank actually holds less... so I just generally figure about a 33% change or 1/3 of the water...

 

[Byron]

Water changes should not depend upon rising nitrates. The point of water changes is stability. Nitrates should not rise from water change to water change by more than a couple ppm. My article at the top of this section of the forum explains this.

Regular Partial Water Changes

Byron Hosking November, 2010 (rev April 2021) Nothing is more important when it comes to aquarium maintenance than regular partial water changes. The adage “an ounce of prevention is worth a pound of cure” certainly applies here. One frequently reads of products that will reduce the need for...

www.fishforums.net

 

[Ichthys]

With 10% changes I’m gonna guess the nitrates are through the roof. Guppies are relatively quite tolerant but even they can only stand high levels for so long. I can see it building up high over the weeks / months.

 

[simonas]

I have always been a heavy water changer but then I usually have too many fish and feed quite heavily.

Currently I do 50% on wednsday and sunday. If I had your tank with guppies I would probably be doing 40-50% once a week . How much you feed is a variable to, if you're feeding too much then they could be dying due to a build up of nastys in the water

 

[Sanityassassin]

Water changes should not depend upon rising nitrates. The point of water changes is stability. Nitrates should not rise from water change to water change by more than a couple ppm. My article at the top of this section of the forum explains this.

Regular Partial Water Changes

Byron Hosking November, 2010 (rev April 2021) Nothing is more important when it comes to aquarium maintenance than regular partial water changes. The adage “an ounce of prevention is worth a pound of cure” certainly applies here. One frequently reads of products that will reduce the need for...

www.fishforums.net

You are absolutely right, I'm not denying that stability in an aquarium environment is essential for the long term welfare of the inhabitants. That's a no brainer.

But in a tiny closed loop environment such as a fish tank, where overstocking and overfeeding are often rife, then that stability is pretty hard to come by, you'd be forever changing your water to fight the negligible rises in pollutant.

Unless you have a continuous drip system running then waste toxin build up is inescapable, even at low increments such as the 2ppm you allude to.

Nitrate, although far from being the only "nasty", is a good measureable pre cursor to determine your water quality, and the hobbyist can work their water change schedule around that.

It's not ideal, far from it. You're never going to replicate the vast open expanse of a natural waterway in an overcrowded puddle!

We can but do our best given the tiny environments we are working with.

 

[Lcc86]

When I initially upgraded to my 29g I didn't know how often water "needed" changing so I tested my parameters all the time to see, and nitrate levels started rising after about 10 days. I don't use that as a strict guide, I tend to do a 75% change every 7 or 8 days depending on my schedule. I still test the water before every change just to see what the parameters are but rarely leave it longer than that. My tank is planted and understocked so I potentially have more leeway than someone with a more heavily stocked tank but I don't like to push my luck!

 

[GaryE]

I find two things essential. One is impossible for most beginners. That 's not overstocking and overfeeding. Most of us start out with tanks that look like rush hour subway platforms. There's no keeping up there - it's a lot of waste in a small container.
Once you learn to keep numbers reasonable - I do 30% to 80%weekly. And I mean weekly. You have to work with a schedule. I don't test water or go by the kits. If I have extra free time, I do it every 5 days. The longest I go is 10.
I'm not good at routines and schedules, but that one is set in stone.
If the tank is a 10 with a breeding pair of 2 inch/5cm fish , 10% will do. A larger tank with more fish may need 50%. Growing fry may need 3 changes a week.

It's a bit like saying how often do you take your dog out. You must do it. It depends on a bunch of factors. It intrigues me that people will see no problem walking dogs, which take me hours every week and isn't always convenient (the puppy got me up at 5:37 this morning and it's raining), and see a problem in using 30 minutes to care for their fish once a week.

 

[10 Tanks]

How often do people do water changes?
How much do people change?
Ive seen everything from 10% 25% 50%.
I have several tanks and all are fine however I've just got my daughter a small 40l tank with guppies in and at first everything was fine they were breeding and the fry were thriving.
5 months later guppies are dying weekly and I don't know what the problem is.
I do weekly water changes of 10% is that too much? Too little?

Hello Jimmy. I keep a lot of large tanks and besides my tanks, I maintain a large tank for a government office. When you manage someone else's tank, you make real sure you know what you're doing because they paid for their tank, fish and pay you to maintain it. You make very sure they're getting what they pay for. You wouldn't be in business long if you just went about doing your job 10 percent. That's why a 10 percent water change does nothing to maintain the health of a fish tank. A 10 percent water change still leaves 90 percent of the toxins in the water. You need to gradually increase the water changes to the point you change half or more every few days. Here's a rule to follow: Tanks less than 30 gallons need half the water changed twice a week. Tanks 30 gallons and larger need half of the water changed weekly. Plain and simple, if you're not doing this, your fish won't be their healthiest.

10 Tanks (Now 11)

 

[Ichthys]

Here's a rule to follow: Tanks less than 30 gallons need half the water changed twice a week. Tanks 30 gallons and larger need half of the water changed weekly. Plain and simple, if you're not doing this your fish won't be their healthiest.

This doesn’t make much sense. It’s all about relative biomass, and not really anything to do with tank size.

 

[10 Tanks]

This doesn’t make much sense. It’s all about relative biomass, and not really anything to do with tank size.

Hello. The health of a tank is completely about the water. This is because water makes up more of the tank system than anything else. By just following an aggressive water change routine, you remove the toxins before there's ever a buildup. The large, regular water change is the basis of any healthy tank. The rule I posted will ensure a healthy water chemistry and a healthy water chemistry will guarantee the health of whatever lives in the tank. Pretty simple.

10 Tanks (Now 11)