Section R. 325.2155 - Cartridge-type filtersRule 55.
(1) A swimming pool owner shall ensure that a cartridge-type filter system meets all of the following requirements:(a) Is designed for a maximum flow rate of 3/8 of a gallon per minute per square foot of filter area.(b) Is equipped with a means to drain the filter tank to prevent equipment room flooding.(c) Is provided with a spare set of cartridges that is not less than 100% of the required filtration area.(d) Is provided with a means, on the premises and acceptable to the department, for cleaning the cartridges according to the manufacturer's recommendations.Mich. Admin. Code R. 325.2155