doctnj said:
True or not? If so how much do you use?
Your filter will tell you how much. Start small and watch the gauge for a 1 psi jump. If you put too much in just backwash it out and start again. Keep an eye on it. I helped my brother-in-law doing the same thing. Had a 1 psi jump, then several hours later it was 10 psi higher. After several cycles he only had very fine particles floating in front of the light at night.