STN (sps coral dieing from base up) and how to reverse it?

[deputydog95]

I've removed my chemi-pure bag and added about 300 small crabs and snails. Going to let the nutrient levels come up a bit and see what happens. The crabs are decimating the algae growth I already had in there, despite having very low phos and nitrates. Bulbs were old (swapped too) which may have contributed.

 

[21chip21]

Ok, iv had STN 3 times now. No ideas why. Lossing everything again. White from base up. Water stable and no changes. Its a 220 with 75 sump running 2 1/2 years. Been into hobbie for 20+ years and this is beating me. It has a Geo 813 Cal. Reactor with ARMS media, Reef Octopus 3000, Apex controller, Three Radion Pro gen. 3, Three 360w Kessel leds, Two Mp40s, with return pump, Two heaters, ATO, 2 inch Special Blend aragonite, Live rock, Red Sea Salt Blue bucket, Alk. 8.2 Cal. 460, Mag. 1350, phosphate 0, Nitrate 0. WHY???

 

[markalot]

I can't give you a definite answer, but if PO4 and NO3 are really 0 then that's part of the problem. I would run Alk at 7 to 7.5 and find something to feed regularly that won't pollute too bad (reef roids, reef chili, Red Sea Reef Energy ...), the acros need some food in the water to stay healthy.

In a perfect world you would be able to keep PO4 and NO3 near 0 and always have fine food in the water for the acros to eat. In the real world sometimes having some detectable PO4 and Nitrates around 5 leads to healthier acros. I can preach this like I'm an expert but I continue to fail to find the right balance. :facepalm:

I would also be wary of the LED's, perhaps they are brighter than they look? Have you ever measured PAR? T5s do well 300 - 400 and at the same time all LED seems to do well at 200-300.