They are easily hatched and their eggs may be stored dry for years. Buffers may be formulated to adjust the pH to a particular value, or to raise the alkalinity without changing the pH. calcium chloride CaCl2. This is a form of calcium that may be added to reef tanks to maintain the calcium level. See kalkwasser . This filter consists of a canister external to the aquarium which is filled with various media, mechanical or chemical .
Hoses run to and from the canister, and an attached pump forces water through the canister.
These can be very efficient filters, though they must be taken apart and cleaned regularly. These filters use chemical processes to clean the water. Examples are protein skimmers and any filter containing chemical media such as activated carbon , molecular adsorption pads , or resins. A device which makes aquarium water cooler. They generally cost at least several hundred dollars, and home brew solutions involving small refrigerators are seldom successful.