Of all the supplements available for your saltwater tank, the one that is king amongst all them is kalkwasser. a.k.a. "kalk".
Kalk is highly effective in keeping your tank's parameters as stable as possible and it is very cost effective. It is also part of the hidden secrets on how to keep a thriving reef tank.
Be careful though - using kalk incorrectly can ruin your saltwater tank. Lucky for you, in this episode of Mr. Saltwater Tank TV, I take you through what kalk is and how to use it safely in your tank.