In addition, many low nutrient disciples who don't use Zeovit seem to experience intermittent periods of cyanobacteria. Since cyano is a bacteria and not an algae, it can feed off the carbon source you're providing and show its' ugly maroon matting every six months or so. I got sick of it!
I was carbon dosing vodka and vinegar in my last tank and dealt with cyanobacteria blooms about twice yearly. I got tired of being told to feed more, because no matter what I would register 0 nitrates, and get cyano. No matter what anybody tells you, the non-Zeovit carbon dosing methods will take nitrates to 0, but won't help eliminate phosphates. Most vodka and vinegar dosers still run GFO anyway. You're then told to dose amino acids to add some nitrates so that you can tip the scales and lower phosphate, because it won't come down due to being nitrate limited. I wanted to pull my hair out! It is much easier to deal with nitrates than phosphates in an SPS system, and your rock can only absorb so much before it releases it back into the water column. I finally broke the tank down when I got sick of my rock leaching the PO4 that carbon dosing was hyped up to help control. I've gotten much better results in my new system by using tried and true "old school" methods. I do a 10% water change every other week, feed a small amount of fish very well, and run GFO and carbon in a reactor to keep phosphates in check. I purposely keep my nitrates between 2.5 - 5 ppm, and change my gfo out when phosphates reach around .05
IMHO, keeping some nutrients in the water column via single digit nitrate readings is equal to dosing amino acids and all the other expensive supplements that ULNS tanks need to survive. As long as you can keep phosphates in check with a good test kit (I use a Hannah Checker) then you won't necessarily need all that stuff. You also have more leeway in where you'd like to run your calcium and alkalinity levels than ULNS requires.
Zeovit has a much more successful track record of being able to export/adsorb both nitrates and phosphates, but for me it keeps SPS corals on the edge at all times. Since I have a work schedule that changes from day to day, it's next to impossible for me to stay on top of the dosing, supplementation and monitoring that Zeovit requires. I also don't like that nobody knows exactly what's in the blue bottled potions that Zeovit sells. I wonder how much of them are actually necessary, and as they say...a fool and his money are soon parted.
Zeovit works, but so do algae scrubbers, big skimmer Berlin Systems, and refugiums at a fraction of the long term cost.
Just my .02
