I know quite a few folks dose nitrate and phosphate in their systems but I didn't see a lot of first hand accounts here so I thought I'd share my own "whys and hows." I set up a 60g frag tank this summer and it's been coming along nicely. What does one do with a lot of space for frags? Well, fill it up of course! There were standard new tank issues to overcome but it really started getting in a nice groove in early September. Corals were all growing well but their colors stank. I had two obvious issue that I needed to correct - alk swings and low nutrients. I fixed the Alk swings by bringing the doser I had been too lazy to set up online. The nutrient issue was dealt with by doing water changes with "used" water from my main tank. Alk? Check. Nutrients? 5 NO3 & 8 ppb phosphate. The colors started coming back even better than before and I went back to my regular schedule maintenance. A few weeks later I noticed a few corals starting to lose their color again and since I had a few weeks of stable Alk, I tested for nitrates and phosphates and they were barley detectable. I had noticed some macro algae wasn't growing too well a week or two before but didn't connect the dots at the time. I went back to doing water changes with "used" tank water for a few weeks and still couldn't get the levels up. The macro algae started growing again but it sucked NO3/PO4 up so fast that I couldn't ever get detectable levels. So I decided to dose nitrate while I looked for a more permanent solution. (I decided to get additional phosphate by feeding more Full Spectrum pellets)
I did some research and decided to not use the standard stump remover (potassium nitrate) and went with food grade sodium nitrate (NaNO3) instead. It helped that @anit77 had a 5 lb bag that I could "borrow." I dissolved 25g of the NaNO3 is 300mL of RODI water and started dosing! Using a Salifert test kit, I was reading next-to-nothing or less than 0.2 ppm. I added one mL of the solution and waited an hour. I again tested and got a slight increase up to a firm 0.2 ppm. I added an additional 2 mL of the solution and right before I went to bed tested at a solid 0.5 ppm. This is still pretty low and far away from my target of 2 ppm but it's a start. I don't want to do anything too fast and make a headache for myself. Plus, I just left for a work trip this morning and wanted to make sure I didn't screw something up right before I left. For my system it appears that a 2mL dose of the solution raises my nitrates by 0.2 ppm. I don't want to make dosing nitrates a permanent thing but I do want them in a somewhat reasonable range while I work on a more permanent solution. I'll test again later this week when I'm back in town a probably dose a few more times while things get sorted out and I'll keep y'all posted.
I did some research and decided to not use the standard stump remover (potassium nitrate) and went with food grade sodium nitrate (NaNO3) instead. It helped that @anit77 had a 5 lb bag that I could "borrow." I dissolved 25g of the NaNO3 is 300mL of RODI water and started dosing! Using a Salifert test kit, I was reading next-to-nothing or less than 0.2 ppm. I added one mL of the solution and waited an hour. I again tested and got a slight increase up to a firm 0.2 ppm. I added an additional 2 mL of the solution and right before I went to bed tested at a solid 0.5 ppm. This is still pretty low and far away from my target of 2 ppm but it's a start. I don't want to do anything too fast and make a headache for myself. Plus, I just left for a work trip this morning and wanted to make sure I didn't screw something up right before I left. For my system it appears that a 2mL dose of the solution raises my nitrates by 0.2 ppm. I don't want to make dosing nitrates a permanent thing but I do want them in a somewhat reasonable range while I work on a more permanent solution. I'll test again later this week when I'm back in town a probably dose a few more times while things get sorted out and I'll keep y'all posted.
