I did a 20% waterchange on my 75g yesterday. Came home today and my BTA has wilted down to almost nothing and my crocea is'nt opening all the way and the mantle looks like it is receeding. My params are nits 10, mag 1000, ca 640, KH 8, PH 8.2 and my phos is .02. The only thing that I added last night was Two Little Fishes Iron Concentrate with manganese. Can anyone tell me what is up and do I need to do another water change? Can't take pics, camera out of commission. Sorry!