Update: I did notice some yellowing/ browning on my growth shoot and a little yellowing of old leaves which is very concerning to me as I really want this to be a mangrove tank. So I used a single Seachem root tab inserted in the grave around the mangrove. 2 days later po4 is now reading .02, could be unrelated? No other changes. I did order a icp test to further understand my water chemistry. Tank is really looking good, nuisance algae is nearly gone and coralline is popping up everywhere, 5 months in fingers crossed.