My phosphate doesn’t exceeds 0.1 usually less. I use Hanna instruments and every few weeks lfs to confirm the readings. I add micobacter 7 and clean few times a week to help control the cyno.
Vodka, I was thinking about it celebrating the New Year with the corals lol.
I used 50g sodium nitrate per 1 liter of water for my solution. According to my calculations, it is about .25ppm per 1 ml. Today I dosed 14ml, I have been increasing the dosage 4ml a day. so now I am dosing about 3.5 ppm. If you are using the same concentration of sodium nitrate, It seems that I am on the right track if I continue that path since you are using 40ml per day. My corals seems happier since I started dosing but I am still concerned not to make a costly mistake.