Maximum Safe Water Change

[dallasfrog]

I have a 29 gallon FOWLR tank - no sump or skimmer - with the following livestock:
2 green chromis
1 clown fish
1 bicolored blenny
2 turbo snails
4 hermit crabs

I can't seem to get my NO3 down to zero. It stays between 20 and 40 no matter what I do.

How much water can I safely change in order to manage this?

 

[carey]

Excellent question! I'd love to know the answer too. I'm doing 10 gallon changes in my sw 29 tank. I did a 15 once but I don't have fish or much in it so I'm not sure if what i did was good. lol

 

[Smitty]

As long as the water is of the same salinity and temp I don't see why you can't go for large 50% or so water changes. The water doesn't have the bacteria in it so that shouldn't hurt. Plus, many people will be told to do massive water changes to help get Nitrates and Ammonia down.

The thing to be careful of is if you have any corals that can't be out of the water, make sure they will be under the water line during the water change.

 

[carey]

Thanks for the quick response smitty. Good information to have. All my corals are on the sandbed for now since I'm doing back to back pwc's to try to get rid of phosphate issue.