What’s happening with my SPS corals?

[BaileysTank]

So my sps corals are dying off but it’s very strange…
So I have 2 digitalas in the tank and both have been bleaching from the base up. My monitors on the other hand has been doing fine and is encrusting over the rock it’s on. I run 2 gen 4 raisins both on the WWC mixed reef pre set at 75%. I have 4 wavemakers, it is a 90 gallon display with another 30 gallons in the sump. I run carbon, protein skimmer, and I have a succeful refugium. Parmaters: phos:0 (don’t have low range phos or nitrate tests so bare with me) nitrate:0 ammonia:0 alk:8.9 calcium:460. I do dose phosphate and nitrate (I know it’s redundant becuase I run a refugium, I enjoy the look of my refugium and that’s primary why I run it) any other questions please ask but I’m really just lost on why these corals are on there way out

 

[Graemesreef]

From your #s it looks like they could be starving. Try to slowly raise your phosphates and nitrates. You might have to cut whats good off as its really hard to stop once the process has started. Cant really tell without a good pic?

 

[Stephen Glover]

Low nutrients with higher Alk can cause this. Invest in better test kits Hanna phosphate checker and Salifert nitrate test kits are well worth the cost.

 

[Lavey29]

0 phosphate and 0 nitrates equals corals starving to death. This decline can take weeks or months to show visible distress.

 

[LOVEROCK]

Get more fish

 

[ScottB]

Yeah like everyone else will say, 0/0 is a razor thin nutrient margin. I saw that you are carbon dosing and some can run 0/0 residuals that way and have a very successful reef. However, unless you are feeding very often and very much it won't work well for long.