Magnesium is an often overlooked ion found in sea water.

Often the only time a hobbyist considers testing for it, or supplementing, is when an aquarium is having problems maintaining constant alkalinity and calcium balances.

For the purpose of this article we are not going to demand you test, or even dose magnesium at regular intervals. The purpose is to inform you of magnesium’s function in reef aquariums, and educate on the possible side effects of magnesium deficiencies in marine aquaria.

Please also refer to our other helpful brochures on water quality.