[daniella3d]

well, water of 30 to 40 ppm of nitrates and .25 of phosphates is anything but "too clean".

I don't think that would be the reason for RTN though, because my nitrates are quite high right now and phosphates around .15 but I have no problem with my SPS, even the delicate ones.

I suspect a mixt of things, probably water quality, the light, and probably stability is pushing your SPS on the limit of their endurance.

I would not keep any leather corals with SPS. They are not very compatible and migth trigger chimical war. I avoid leather corals all together.

I would lower the nitrates with dosing with NOPOX, and use GFO to lower the phosphates, plus I would make sure the parameters are very stable with dosing for KH and calcium with a dosing pump. Make sure the light is not too strong. This is a good factor for RTN when the light is blasting the corals and LED is very strong and corals need acclimation for it.