Hello. I did 3/4 water change on Sunday. Levels all really good afterwards. Today, doing my normal test, PH at 8.2 Nitrite at .50 ammonia 0 Nitrate 40+ Dont know what happened. Tank is a few months old recently added plants to the system so that is why I did the drastic water change (one of them died ; Halymenis Sp. it was nasty to get out cleaned everything pretty good. What should I try now? The fish dont seem to be bothered by the Nitrate spike. The Nitrite is up too not sure why.