A water treatment agent for boilers which comprises as active ingredients a compound which can release aliphatic hydroxycarboxylic acid ions in water and a polyamine represented by the following formula (I) or an acid addition product thereof: (wherein n denotes an integer of 2 to 5), and a water treatment method for pure water boilers or soft boilers using the above active ingredients to prevent corrosion of the ferrous metal in the water system of the pure water boilers or soft water boilers.
A method of detecting the initial concentration of a water-treatment chemical present in a diluted aqueous system, by (1) incorporating into the aqueous system, a mixture including a known amount of the active ingredient and a known amount of an ultra-violet sensitive compound having the formula (I): ##STR1## wherein halogen is chlorine or bromine; X is ##STR2## and a and b, independently are 0 or 1; M is hydrogen or an alkaline metal ion; and (2) detecting the concentration of the compound of formula I, by exposing to ultra-violet light a sample of the aqueous system so treated.
A system for treating a portion of water passing through a pressurized water conduit. The system comprises water treatment means such as a reverse osmosis module. An upstream branch line communicates between the pressurized water conduit and the inlet of the water treatment means. Another branch line is provided for connection with pressurized water conduit at a location downstream from the upstream branch line, and communicating with a water outlet of the treatment means. A flow restrictor is provided, positioned in the pressurized water conduit between the conduit connection locations of the respective branch lines. Thus, water can flow through the upstream branch line from the conduit to the water treatment means, and water can flow from the treatment means through the other downstream branch line back to the conduit when water is flowing through the pressurized water conduit.