Leave product in place for 4 days, then test phosphate or silicate
concentrations with either MultiTest: Phosphate or MultiTest: Silicate. If the
concentration of the component you are trying to decrease has not dropped to
around 0.02 mg/L, then replace the PhosGuard, otherwise leave in place until
levels begin to climb again. As long as concentrations remain under control, the
product is not exhausted. Over treating is not recommended. PhosGuard is not an
exchange resin and does not release anything into the water. It does not leach
phosphate or silicate back into the water and may be removed, dried, and
returned to service until exhausted. Continuous use of small quantities is
better than intermittent use of larger quantities.