(A) Filter capacity on all pools required to have filter systems shall be such that they need not be cleaned more frequently than once every 2 days under normal conditions of operation. Performance charts of the filter manufacturer shall be available.
(B) All filters shall be equipped with influent pressure gauges and an effluent pressure gauge to determine the pressure differential and frequency of cleaning.
(C) Each filter shall be provided with a visual means of determining when the filter has been restored to original cleanliness.
(D) Operating instructions shall be posted on every filter system and all valves shall be properly designated with weatherproof tags, indicating purposes.
('69 Code, § 6-114)