Nitrate & Plants   Calculate how much plant growth you need to keep nitrate levels constant. 
Water changes & temperature   Calculate how much the temperature changes in your tank when changing water with a different temperature. 
Water changes & pH   Calculate how much the pH changes in your tank when changing water with a different pH. 
Nitrate water change   Calculate how much water to change to reduce the nitrate in your aquarium. 
Ammonia dosing for cycling   Calculate how much ammonia you need to add during fishless cycling. 
Bicarbonate (KH) dosing   Calculate the amount of sodium bicarbonate is needed to reach a certain KH level. 
Calculate pH from KH and CO_{2}   Calculate the pH value for a certain KH and CO_{2} level. 

Pleco cave size   Calculate how big the cave needs to be for a certain size pleco. 
Substrate volume & weight   Calculate how much substrate you need for your tank, based on the size of the base of the tank. 
Aquarium volume and weight calculator   Calculate the weight of the aquarium, including glass and substrate 