Note that the natural seawater concentration of potassium is ~399 ppm; maintaining the potassium concentration in marine aquaria as closely to this value as possible is recommended.
Shake product well before using. Add 5 ml (1 capful) of product per 50 US-gallons of aquarium water every other day or as needed to maintain the potassium concentration within a range of 390 - 410 ppm. When used in this fashion, 250 ml treats up to 2,500 US-gallons
Determine the potassium concentration in the aquarium using an accurate test kit before supplementing. Shake this product well before each use. Each ml of Potassion will increase the concentration of potassium (“[K+]”) in 1 US-gallon (3.785 L) of water by approximately 21 ppm. If the initial [K+] in the aquarium is below 390 ppm, add this product at the maximum rate of 10 ml per 20 US-gallons daily until the potassium concentration measures between 390 - 410 ppm, then dose daily or weekly as needed (see below). Always try to maintain the [K+] within a range of +/-10 ppm. To determine the dosing rate of this product once the desired [K+] has been acquired, measure the daily rate of potassium uptake (i.e. the decrease in potassium) in your aquarium by measuring the [K+] at the same time each day over a one- to two-week period. To determine the daily dosing rate (preferable to weekly dosing) for potassium maintenance: estimate the volume of water in the entire aquarium system; divide the daily decrease in [K+] by 21; multiply this number by the volume of water in the system to get the daily dosage required (ml) to maintain a stable [K+]. Daily dosing maintains a more stable [K+] (and more natural environment) than dosing weekly, in which the [K+] spikes just after dosing and then gradually decreases throughout the course of the week.