whats the biggest water change u can do?

got a problem with high nitrates and ich

so wanting 2 do a big water change in a 94lt tank

what would u guys suggest? 25%? or more

 

I have heard of people doing a 50% water change. I wouldn't do anything more than that.

 

Is it a reef or fish only tank? I have done a 75% water change before but i made sure the SG and Temp were equal before I did it. It was a fish only at the time.

 

mainly a reef only tank, also got a couple of mushrooms and polyips but more interested in me fishies!

 

If you match the parameters very well, you can do 100%. You would probably need to take everything out and put it in buckets though. To keep everything from being exposed to air too long. Then transfer everything but the water back.

Water changes will do nothing for ich though, and really nothing for nitrates long term. It will short term though, but nitrates are not toxic and water changes can be stressful, so this dosn't seem worth it. The only way to reduce nitrate long term, is to remove the source and do regular small water changes.

 

okay cool,

thanks for ya help peps

 

When I upgrade tanks, sometimes a 200% water change, just because of the new tank being so large.

 

Personally I go with smaller-medium water changes, normally at most 25%. My theory is to not make lot of changes. SG, trace elements, say even nitrate fluctations can all make large jumps with big water changes. I look at it as a continuation of the 'go slow let it grow' mentality.

 

I've done 50%-75% water changes on reef systems. you just have to be very careful with matching the water parameters.

 

I've really only done up to 50%

I don't like changing too much at once unless I have to. If you end up in a position you need to change more than 50% you probably need to keep a better eye on your parameters and do smaller changes more often to keep them in check.