
That is true. Make note that filters can get dirty in a normal fashion from dust and debris. We generally recommend cleaning the filter when the pressure increases by about 25% from the starting (clean) pressure. But excessive organic material can lead to algae. When you see green or a quick spike in filter pressure, you probably have algae which would require the SLAM Process to kill/remove the algae properly. Don't fall for pool store gimmicks or products off the shelf, they are a waste of money. Liquid chlorine maintained at the proper SLAM level (based on your current CYA) is the key. With chilly water, now is the best time to do a SLAM Process. Also see our FC/CYA Levels for FC-to-CYA balancing.but said it was more likely pressure from a dirty filter. Apparently that can cause pressure,