Recommended No3 + PO4 levels according to Alk levels?

[ConsummatePro]

I recently became aware of recommendations that tanks with higher Alk tend to need higher NO3 and PO4 levels. I was previously applying generic NO3 1-5, PO4 0.03-0.05 "broad target" irresepective of Alk, but is there a more nuanced recommendation according to Alk levels? ie if running alk > 9 do you recommend higher range NO3 & PO4?

Right now I'm struggling with SPS's (even montis, digis, birdnest died after growing well) and I have now gotten better NO3 and PO4 levels (they were close to zero before when my bordsnest died, I now feed more). As of today my tank shows: Alk 9.08, Ca 462, Mg 1404 (all via Trident), Hanna: PO4 0.16, NO3 6.9, pH 8.04-8.19. Temp 78 F. Salt 34.5-35. These all look good to me.

I've not seen any "table" of recommended nutrient levels by Alk, but would that be a good thing to recommend/discuss or is that over thinking it?

Eg: Alk 8-9, 9-10, 10+ with correlating recommended nutrient levels?

 

[Spare time]

Eh, just avoid ULNS numbers and you are fine to run whatever alk you choose. Or, just have sufficient input of nitrogen and phosphate sources.

 

[Randy Holmes-Farley]

I recently became aware of recommendations that tanks with higher Alk tend to need higher NO3 and PO4 levels. I was previously applying generic NO3 1-5, PO4 0.03-0.05 "broad target" irresepective of Alk, but is there a more nuanced recommendation according to Alk levels? ie if running alk > 9 do you recommend higher range NO3 & PO4?

Right now I'm struggling with SPS's (even montis, digis, birdnest died after growing well) and I have now gotten better NO3 and PO4 levels (they were close to zero before when my bordsnest died, I now feed more). As of today my tank shows: Alk 9.08, Ca 462, Mg 1404 (all via Trident), Hanna: PO4 0.16, NO3 6.9, pH 8.04-8.19. Temp 78 F. Salt 34.5-35. These all look good to me.

I've not seen any "table" of recommended nutrient levels by Alk, but would that be a good thing to recommend/discuss or is that over thinking it?

Eg: Alk 8-9, 9-10, 10+ with correlating recommended nutrient levels?

There's no exact table around that I have seen, but in general, i recommend 2-10 ppm nitrate and 0.02 to 0.1 ppm phosphate, and if the alk is on the high side (say, above 8.5 dKH), I'd veer to the higher end of that range, and definitely not below it, especially if you have certain SPS corals that can get burnt tips.

The tip issue may be from the coral depositing skeleton faster than the tissue can keep up.