Hi Robert !! Well I Finally Finished My Egg Crate System About 2 Months Ago . I Added It To An Existing 2 Year Old Tank . The Problem I Am Having Is Alkalinity. Seems The Level Stays Around 16 Dkh . I Do Water Changes , 10 Gallons A Week On This 75 Gal. Tank. I Have Tried Using Reef Builder Carbonate But It Does Very Little Change . My Calcium Is Great , I Use The Drip Method Using Pickling Lime. Calcium Is 400 . What Can I Do To Get The Alkalinity Right ? Is It Being Used Up That Fast ? Thanks !!! john What test kit are you using? Red Sea are notoriously inaccurate... What Salt mix IO? is closest to replicate/maintain high calcium content Here is a handy calculator http://www.andy-hipkiss.co.uk/index.htm?http://www.andy-hipkiss.co.uk/caalkcalc.htm IMO alkalinity is one test that can keep you chasing your tail as the chemistry in the tank is constantly changing. (A natural occurance) and reacting to alkalinity reading can do more harm tnah good. You could of course try C-Balance but its expensive. The most straingforward method is to use a good salt IO or coralife and adding kalkwasser for all makeup water.Providing your tank isnt overcrowded (high nitrate) your should have an acceptable alkalinity reading.