I been checking the filter daily, but haven't backwashed in over a week because it was only up 3 lbs. After reading your post I decided I'd better backwash and, wow! what nasty stuff came out - green foam and very dirty water.

After backwashing and rinsing, the filter pressure settled back to 16 lbs, and I noticed the ripple on the water is a bit stronger (the return is pointed upwards for aerating). I have some Fibre Clear - should I put a few handfuls down the skimmer (until the psi increases 1 lb) to improve the filtering efficiency?

Around 5:30p the shotglass test result was between 3 and 5 (15ppm to 25ppm) so I added another .8 gal of bleach. I retested about 30 minutes after adding the bleach and it was a definate 5 (25 ppm).

I'll test again at 8pm this evening and dose as needed to bring it back up to 25ppm. Tomorrow is a work day, but I'll treat it at 8am, sneak home for lunch and again around 6p. With the filter newly backwashed, I'm hoping for improvement on water clarity.

By the way, I've seen in other posts that some pool owners have problems with their pump being too strong for the size of their sand filter. I don't think that is true for me, but here's the info. I put a new pump on in May because the old one had burned out. Same HP (3/4) and brand (Hayward) but the new pump is a Super II model. It is stronger than the old once as the psi through a freshly backwashed filter is 16 while the old pump was around 12. The connections on the pump are 2" but I have them stepped down to 1 1/2" to fit the rest of the piping. The multiport is rated 125 GPM, the filter capacity is 275 lbs of sand. The new pump is rated with a maximum output of 63 GPM at 40 ft of head (down to 31 GPM at 70 ft of head). My pump is below the level of the pool, about even with the bottom of the deep end. There's about 15 feet of pipe back to the return - so I'm guessing the pump performance output is its full capacity of 63 GPM. Do you think that the pump size is reasonable for my filter and set up?

Thanks again.