Sodium Nitrate

[Docdiggy]

I was dosing this a while ago and stopped. I did OD it on the very first dose many months ago. My sps never really recovered, but lps looked nice. Well my most recent tank is a 125 with 55 sump. I only have 4 fish though and they get fed a lot, but it's impossible to get any nutrients in the water this way. I tested yesterday and got 0 nitrate (red sea) and 0 phos (Hanna ultra low) which is probably why my sps are just about dead and some sps are great and others could look better. I believe when I originally overdosed it plummeted my phos causing problems. Well I'm going very slow this time and since I'm not getting a phos reading what problems could I run into just dosing nitrate? There's really not much phos that could drop. Alk read 8.5 yesterday (salifert).

 

[lapin]

My suggestion is you dose both nitrate and phosphate. Coral use both. One without the other will cause issues like dead coral.
Corals need phosphate to utilize nitrogen. If corals do not have enough phosphate to utilize nitrogen it causes the coral to start making sulpholipeds instead of phospholipids which makes coral very sensitive to changes in light intensity and and temperature. It also forces the coral to store the excess nitrogen as uric acids crystals inside the coral cells and as they grow the crystal rupture the cell walls.

 

[Docdiggy]

I thought about both, but I also don't know how much faith I have in that Hanna tester. Their acceptable ranges have pretty big swings.