As I stated in a different thread nightly kalkwasser drips seem to prohibit cyano growth where my system is concerned. Cant hurt to give it a try with your system.
I mix a tablespoon of kalk powder with just enough white vinegar (about a shot glass) to thoroughly dissolve the powder in a gallon jug and the rest ro/di. Then just slowly drip into your system as you would to acclimate a new fish arrival. I shoot for about a drip per second.
Whether it makes chemical sense or not the results for my system is a elevation in PH to around 8.4 and a slight increase in my alk reading. Cyano seems to hate this. In fact just recently I noticed some cyano beginning to grow in the corners of my display I resumed kalk drips that I had been neglecting and the existing cyano actually died off with no changes to my water change routine. Like you all relative levels where fine; nitrate 0 and phosphates undetectable. However if I discontinue kalk drips cyano will reemerge
It has also stated in other threads that using vinegar in kalk mix may actually fuel cyano growth which makes chemical sense. The only reason I use a small amount of vinegar is to break down the powder thoroughly so I don't have to let the mixer settle out prior to use. If you want to give the solution time to settle out on its own you don't have to use vinegar at all. Seems to make no difference where my system is concerned as it is a small amount of vinegar in relation to what is normally recommended for this method.
Like I said it cant hurt to try just keep an eye on your PH and alk readings until you get a gauge on how much mixture and drip rate is right for your system. Even if it does not help with the cyano problem the reef seems to love kalk drips in general. It will also maintain calcium levels which is the normal reason for kalk drips and percipate out phosphates which could be the reason for its success in killling off my cyano rather than the elivated PH and alk.
Hope this helps and good luck with the tank.
