Water Changes - How Much Per Day?

[STD]

I am trying to get rid of a ridiculously high nitrate level in my tank

I did a 20% water change yesterday and again today

My plan is to do the same every day until my nitrates are down to a low level

I'm thinking about doing another 20% this evening

Is this too much?

 

[CFC]

You can never change too much water unless the water you are replacing the tank water with is of vastly different parameteres. Just make sure the water temperature doesnt drop by more than 3 degrees during the addition of the new water as some fish dont handle fast changes in temperature well. In an ideal world we would change 100% of the water every day but it would be impractical and expensive unless you were running very small tanks.

How high are the nitrates?

 

[STD]

You can never change too much water unless the water you are replacing the tank water with is of vastly different parameteres. Just make sure the water temperature doesnt drop by more than 3 degrees during the addition of the new water as some fish dont handle fast changes in temperature well. In an ideal world we would change 100% of the water every day but it would be impractical and expensive unless you were running very small tanks.

How high are the nitrates?

Yesterday they were off the scale

After my changes they are down to about 100

 

[Bignose]

This is just to echo CFC, so long as the water parameters are in the neighborhood, it isn't a problem at all. If you are getting the water all from the same tap, and have always used the tap water, and never added any pH altering chemicals or chemical buffers, you should be fine. You are looking to keep the temp, pH, and KH the same.

If a tank has gone a very, very long time without a water change, the pH is very low, and there is ammonia present, then you can't do quick water changes. But, that is a very rare, very delicate situation.

If all you have is high nitrates, you are fine in doing water changes. You can even do larger than 20% if you want, though 20% every day for a week or two will be very good.

 

[Tolak]

Once you have done a few 20% changes a few days in a row it would be safe to do some larger changes, 50% to 80% would be fine. As was stated by CFC & Bignose, as long as everything is pretty much the same large water changes do no harm.

It would be best to find out why the nitrate levels are so high, until then you are treating the symptoms, not the problem.

 

[Luketendo]

Test the tap water.