Coraline Die off
 

Hello all,

Its been awhile but the tank has been up and runing for 3 months now. Water has been on roughly a weekly schedual of WC, ok sometimes every two weeks. I use only RO/DI water. I have a small CUC purchased from Reef Cleaners, two small clowns, a coral banded shirmp, 1 royal blue dottyback, one blue damsel, and one coco worm.

My tank was developing nicely up to about 2 weeks ago. Prior to that time I could see the purple forming on the rock in small clusters and spreading. Nothing near the level of full blown blooms. Each day I could see more and more. Then all of a sudden its gone, well not all of it but most of it.

I am having an influx of QTIP Sponges popping up in the tank right now, but research says they are not a bad thing.

The fish are happy and the coco worm is growing nicely.

Water parameters are:

Salinity: 1.024
Temp: 76
Ammonia: 0
PH: 8.2
Nitrite: 0
Nitrate: 0 or just a little above 0. API test kit doesn't show anything between 0 and 5.0
Calcium : 420

I am wondering if there is anything wrong or I should be testing for something in order to diagnose the coraline die off.

You also need to be testing for Phosphates, ALK, and Magnesium.