I notice a decrease in water flow coming out of the the pipe from my ATS around three days after a cleaning and slowly gets less and less. Its hard to tell how the flow is on the screen with the algae growing on it. I assume this is from algae growing up to the pipe slot. Is this a concern? how do I go about fixing this if it is an issue. My ATS is 15" long X 3" wide vertical fed by 540 gal/hr pump. The pipe with the slot holding the screen is 1/2" pvc.