Hi I’m new to hobby I have a 12G cube bin running 6 month 4 with live stock I only have one blue damsil at the moment I have bin feeding some corals with mysis shrimp think I over done it my nitrates have gone up to around 20 ammonia nitrite and phosphate are all undetectable what is best course of action I don’t have a sump and have minimal space left in the 3 compartment At back of tank bin researching but there so many option not sure what’s best


