o have an 200L tank runnig an fluval 204
have 2 pictus
2 eels
2 clowns
1 bgk
what i want to do is empty tank out take out all gravel to be replaced with crushed coral and give good clean. What are my best options to keep most of water to put back in tank so i dont have to recycle tank, all i'm keeping at moment are the pictus cats, how long should i wait before before adding the chiclids i want to get 5 yellows and 5 of somethin else .
any advice apreciated cheers