White tips on SPS

[Frogger]

If you are growing any scleractinian corals (stoney corals), snails, clams, coraline algae, etc you need to be adding a balanced calcium and alkalinity supplement.

The easiest way is a balanced calcium chloride, sodium bicarbonate/carbonate additive. Work slowly to find a balance ideally between 7 and 10 dkh and 400 to 440ppm calcium.

Also having truly no phosphates can be a problem that will cause the tips to go white and dieback. Reduce GFO if you are using it.