Quote Originally Posted by mathias
whats wrong with just adding a lil to my sump?
1. Adding the straight solid to the tank can cause a large and rapid swing in pH. Not good.

2. Kalk is a very fine powder, like flour, and it will probably end up being sucked into the pump. Unddisolved Kalk powder will basically kill anything it touches. Since it souch a fine powder, its not going to settle in one place and slowly dissolve. It'll probably get blown all over the tank.

3. Adding solid Kalk at one time will cause a localized high pH, high concentration area that will cause scaling. This will have the effect of not adding any calcium and reducing the soluble alkalinity levels. Definitely counter productive. This can also have the effect of causing your skimmer and return pump to scale and seize up and possibly burn up. Scaling always seems to occur in pumps first due to the fact that the pressure change that occurs as you go through the impeller catalyzes scale formation.

4. Your skimmer will probably also go crazy. By adding that much alkali at one time fats go through a chemical reaction called "saponification." Basically, you are making good ole fashioned lye soap.

Other then that, there is nothing wrong with adding Kalk directly to the sump.