Alkalin 8.3 Liquid Size:500ML this is a result of SIZE:500ML this is a result of the chemical mechanism by which phosphate test kits operate and does not indicate that the product has failed to perform its intended function use the product only as directed and decrease frequency of usage if the presence of cyanobacteria or nuisance algae increases during periods following addition of the product to the aquarium in which the alkalinity spikes just after dosing and then gradually decreases throughout the course of the week Add product at the maximum rate of 5 ml (1 capful) per 30 US gallons daily until the desired alkalinity is attained