I have a 90 gallon tank (with a 30 gallon sump). I currently use about 1 tbsp. of kalk per gallon of water in my ATO (in total I have a 5 gallon ATO - so I add about 5 tbsp. of Kalk in total). I am currently struggling to keep my nitrates below 10 or 15. I'd like to try adding vinegar into my ATO as well to see if this can help reduce my nitrates and improve some of my coral colors. I hoping that I can try this before going the doser route (not a lot of room in my sump). So, what concerns would I have with adding some vinegar into my ATO/Kalk solution? How much should I add per gallon or 5 gallons into my ATO? Any other watch out's or words of advice. I currently keep my Alk at 8 to 8.5, CA at 410 and Mag at 1300. I do run GFO/Carbon in a doser if that matters at all.