[rvitko]

I hope this thread will answer the most FAQ. The electronic Streams have a safety feature that sound an audible alarm when the pump is jammed. The pumps vary in the frequency they need cleaning with the habitat they are used in. In my personal opinion I keep my tanks at about 380-400 ppm Calcium, I don't use magnesium or strontium supplements (any supplements except kalk and a calcium reactor for that matter). I keep the KH at 12- I use superbuffer dKH from Kent if necessary. For salt I use hW Marinemix (hW Meersalz in Europe). Why do I do it this way and not keep higher Calcium levels? First of, the reefs are about 380ppm Calcium with a KH of 8, they have the advantage of trillions of gallons of this solution passing over them. I have the advantage as a hobbyist of modern technology keeping the levels reasonably constant as well. I run a slightly higher KH because the KH is more critical to the stability of a closed environment and corallin algae responds favorably and many green algaes negatively to this higher KH. A high KH has also increased the availability of the Ca. By doing this my pumps only need cleaning every 6-9 months- 9 months is pushing it and I wouldn't recommend it. Do my corals grow as fast as 500 ppm- no. They do grow fast enough and the idea of the Optimum Aquarium from Dupla applies to all aquaria, you will always have a limiting factor, by raisng the calcium you only changed it to another element be it light, flow, KH etc. Just work on balance and stability, nature has more experience than all of us.

Why do pumps become jammed with Calcium? The answer is simple and it may surprise you to learn the same thing happens in your pumps as happens at the coral polyp when skeleton is laid down for growth. Inside a pump we have both heat and vacuum, by Boyles law we decrease the solubility of CO2 and the pH increase in a local zone this precipitates CaCO3. Pumps vary in this effect, most pump have an internal temp of 4C over ambient, a Stream is about 1C. Vacuum is hard to quantify. At the coral polyp the xoozanthellae remove CO2 from the water by photosynthetic activity, this does the same thing, the pH increase and CaCO3 precipitates and is added to the skeleton.

Now, lets get down to the pump and cleaning it-