Hi, my tank is about 6 months old and about 2 weeks ago my phosphates spiked to over 3!!! Up until then they have been steady at near zero. I have had issues with high nitrate numbers but with diligent sand bed cleaning and dosing NOPOX along with the addition of a small skimmer they are now steady at around 5-8ppm. All of my livestock looks great, no real changes in fish or CUC, and most corals are great. The only difference I noticed is the past few weeks some of the zoa polyps are closed and have remained that way for awhile now. Some are shut and some open a little while others are fully opened , all in same colony! My colony of fire & ice, dragon eyes, and one of my watermelon are fully open and there are new polyps. Two other small colonies of watermelon are the problem ones. Not sure if that’s related to the phosphate spike and not really sure what caused it or how to lower it. I did nothing out of the ordinary except to really stir up the sandbed in the front of tank. Could that be it? I attached some photos where you can see the difference in the zoa colonies. Any help appreciated, thanks.
