I have a 120 gallon tank that is not coming down from high nitrates. The stock list is a lunar wrasse, long spine pufferfish, dog face pufferfish, zebra eel, miniatus grouper. In the sump I have a algae reactor, a aqua one g220 protein skimmer and bio balls. the nitrates look like they are or above 120 ppm. I have started dosing with vodka 3 days ago and doing water changes with no change on the nitrates. I think I may need to upgrade my skimmer but can not do that with out upgrading my tank as a bigger skimmer will not fit in the sump. Are there any other ways of lowering the nitrates with out upgrading the skimmer?