Yeah the only other option is feed more or stock more to produce more waste. I have small fish In my 40 breed 2 pair skunk clowns 2 pair reverse photon sanjay clowns, 7 chromis 1 yellow tang 1 devil damsel 1 other damsel 1 goby. 15 fish and tank still needs dosingThis helps. Every bit of info helps. I think I need to test more and keep some level of phosphate amd nitrate. Never thought I'd have a problem with too little algae/nutrients.