during the day the pool seems clear, but when I turn on the light at night I see particles in the beam. Is that normal?
If you had a sand filter I would say add some DE to it. I did that and it gave me clear water at night with the light on. I don't know what type of harmsco filter housing you are using but the water better series of filters go down to 0.5 micron. I would imagine if you went to a 10 micron filter, I'm assuming you are using a 20 or 30 micron filter, you would get rid of your floaties. BUT you would have to clean your filters way more often.
If you had a sand filter I would say add some DE to it. I did that and it gave me clear water at night with the light on. I don't know what type of harmsco filter housing you are using but the water better series of filters go down to 0.5 micron. I would imagine if you went to a 10 micron filter, I'm assuming you are using a 20 or 30 micron filter, you would get rid of your floaties. BUT you would have to clean your filters way more often.
+1Not sure about that ... you are seeing the light reflect off the particle which could make it appear larger I think.