Thanks, I acutally viewed that link from another earlier thread and found it useful. However, it doesn't talk about iodine, strontium and the other 60+ trace elements found in Sea Water. Also, some trace elements are exhausted by activated carbon, skimming, reactors, etc. as well as a heavy bio-load. When I first strarted I tried so many different options and then I found tropic marin bio-calcium and realized it is a miracle powder. ocasionally I use a Julian Sprung formula. I don't actually dose with all types of different chemicals, just the previous two additives I mentioned (I use a 1/4 of the recommended dosage). It's been low maintainence and worked wonders on my coral.