Since phosphate products are available in both dry and liquid form, many injection applications are possible. Liquid products can be fed at full strength or diluted from holding tanks. Electronic metering injection pumps can be used to deliver the correct doses directly to the water. Dry phosphates are mixed with water at various concentrations and added similarly. The general consensus is that phosphate should be added as far upstream before chlorine as possible so that sequestering can occur before chlorine can affect the oxidation of iron, manganese or hardness minerals.
Chlorine with out pH asdjustment is oxidative and not very biocidal.