Do I Need To Do A Water Change?

[Inchworm]

There is one rule in fishkeeping that always applies: "When in doubt, do a water change." It will never hurt and can save you a lot of trouble in the long run.

 

[fatheadminnow]

Agree with the above advice^^

Basic math is all that is needed to figure out how much water to change out.

NOTE: Try not to do more than a 50% water change with fish in the tank, as this will really stress them out.

Stick with 30-40% water changes max each time.

And remember:

If fish are exposed to an ammonia level higher than .25 ppm, this will give the fish permanent gill damage.

If fish are exposed to a NitrIte level higher than .25 ppm, this will give the fish permanent nerve damage.

-FHM

 

[tgo]

all great tips, I was just worried that too many changes would do more harm than good, I'll just leave time in between like it was said.

 

[fatheadminnow]

all great tips, I was just worried that too many changes would do more harm than good, I'll just leave time in between like it was said.

Yeah, leave like a half an hour to an hour inn between, and instead of doing a couple large water changes, do more smaller ones.

-FHM

 

[waterdrop]

You'll be kept busy then lol

If your ammonia or nitrITE readings are over 0.25ppm then a water change is required.

Use simple maths to work out roughly how much you need to change for example if your nitrite reading is 1ppm then a 50% change will take it down to around 0.5ppm, wait an hour, do a test, if it is still high, say 0.50ppm for example, then another 50-60% would bring it down below the required level of 0.25ppm

If you have fish in your tank, you will be better doing 2 or 3 changes at 50% a time rather than one 90% change because this would stress the fish too much. Remember to leave at least an hour after a water change before testing or performing another water change.

Andy

This is a very thoughtful post and very good advice and I almost hesitate to complicate the message... but I believe in many cases the 50% thing is a bit of a myth. In typical starting up cases, particularly like the original post here, its unlikely that larger water changes, like 60% or 70% are going to be too stressful, in fact they may be quite the right thing in cases where ammonia or nitrite has ballooned up to 1.0 and higher. The excess toxic exposure is probably more stressful to the fish than any of the milder shocks of larger water changes.

Let me hasten to say that there are certainly plenty of situations that can make it better to do smaller and more frequent water changes. If the tap water does not have zero ammonia and low nitrate, that can argue for being a bit more careful. If one is about to perform the first water change on a tank where water has not been changed in years but has only been topped up, then one is facing "old tank syndrome" as a possibility and water changes should be very small. If one can't do temperature matching then that is a type of factor too.

But in the case here and in the cases of many of our beginners and fish-in cyclers, I think the option of 60-70% changes, especially as a first water change when bad ammonia and nitrite(NO2) values are discovered is a good option. In the end, its up to the individual to work out a good pattern of percentage and frequency when they're having to do it often and 0.25 or 0.30ppm, depending on your test kit, is a good max point beyond which one would need to be changing more water or changing it more frequently.

~~waterdrop~~

 

[backtotropical]

I agree with Waterdrop. The rumour that large water changes will stress fish is a myth. I (as with lots of others on TFF) would advocate anything up to a 100% water change if the circumstances required it.

As Waterdrop says, in 99% of cases the benefit of the water change removing toxins from the tank far outweighs the stress encountered by the water change.

Where water changes to remove toxins are concerned, the bigger the better.

BTT