CarlH

On the water test from the pool place, the CYA level was 51 with "ideal" being 30-200. The pool has had two doses of stabilizer since opening, although I may have backwashed away the second dose too soon. Test strips consistently report stabilizer on the low side of acceptable. Total hardness from the pool place test was low: 102 with 175-225 being ideal. Their test did not report calcium hardness specifically. Iron reading was 0, copper 0.3, manganese was "no". I've wondered if the EZ-Chlor is working correctly because the previous owners had poked a LOT of extra holes in the canisters, presumably trying to get enough chlorine into the system, and may have been using pucks in a floater as well. Since my earlier post, my neighbor who also has a pool and no longer uses chlorine, gave me some leftover 3" pucks, so I tossed two of them in the floater to see if anything comes of it. Since the CYA level was on the low side of acceptable, do you see a problem with that? Thanks for the tips on test kits and I'll be visiting troublefreepool.com now... (2 minutes later) Hmmm, troublefreepool says that 50 ppm is the max for CYA... but pool place test says 200 is the worst, assuming they were reporting PPM. Any speculation on this discrepancy?

After finally getting a very dirty pool clean, I'm having water problems - specifically, not getting any free chlorine reading on test strips. I've shocked it several times over the last 2 weeks, at least 13 lbs of shock in a 22,000 pool, not counting the initial shock at opening (while the pool was still very dirty). Some of those lbs were 73% "super shock" where 1 lb treats 15000 gallons. I took a water sample to the local pool store and they found very high "combined chlorine" but almost no free chlorine, same as my test strips report. The reading on stabilizer was low but within the OK range. Another mystery, the inline chlorinator is a "EZ-Chlor" which has a brand new canister installed. If I put a test strip in the EZ-Chlor's standing water, it shows the highest reading possible. I can see water flowing into the EZ-Chlor, and it's not overflowing, so that water must be feeding back into the pump (according to the pool place, an EZ-Chlor's outlet is supposed to feed back into the pump, unlike some inline systems). But, if I put a test strip in the pool outlet water (using a hose so only outlet water hits the strip), it still reads no free chlorine. The best the pool place could come up with was "keep shocking it every other day". Will that work, or is there something else I can try?

Thanks. That was the right answer. Now that the water is almost clear and all the dirt is gone from the walls and floor, the pressure hasn't risen very much at all 24h after a backwash. Regarding the sand, I have confirmed that the sand is as old as the filter, about 7 years. So it's probably overdue for a change.

Quite true, I have no idea about the sand, but I had the pool company that installed the pool out to help with the startup, and they didn't try to sell me a sand change. Of course that was before I had time to gather the behavior info related here. Once I have all the leaf dirt out of the pool if it still does the same, then you're probably right. Thanks for the post.

I have just acquired a pool and wonder what is normal pressure behavior after a backwash. For background, the pool wasn't properly closed, was full of leaves (most of which are now removed), but still has a lot of dirt on the bottom which will be removed eventually. After intiial shocking the water did clear but got murky again after removing leaves, vacuuming to waste, and brushing down the side walls. All this is complicating the question I'm about to ask but I'll ask it anyway. FYI the filter is a Hayward sand model. 24H after the initial shock the water had cleared (before leaf removal) and I saw a pressure reading of 25 PSI. That was 10-11 PSI higher than immediatley after a backwash, so I backwashed and clearly saw dirty water from the backwash hose. So I figured, 23+ PSI means it's time to backwash. But then I found that the pressure would rise to 23-24 PSI within a few hours of backwashing. And if I backwashed after those 2-3 hours, the flushed water wasn't obviously dirty, nor was there a lot of dirt seen in the sight glass. And even backwashing for only 20 seconds, with a 10 second rinse after, is enough to reduce the pressue to 14-15 PSI. So I'm just wondering what to consider my "normal" baseline pressure and how to judge the need-to-backwash based on pressure. I think I've been backwashing way too often. Perhaps backwashing "loosens up" the sand, causing an initial low pressure, and then as the sand gets packed together again the pressure rises but the sand really isn't dirty (yet)? Thoughts?