Nobody interested anymore? s'okay, I can think out loud in peace.Funny how when I introduced using trichlor pucks I stopped getting other people posting.....
I can report that about 5 weeks after starting the trichlor pucks the CYA reading made it up to around 50. As you know the CYA test is not very precise, but 50 is about the upper limit for what the true level is. Considering I don't really know where the pool was at when I started the pucks (below 30 because CYA was nondetectable when I started, but I added 5 lbs of CYA the week before) that means that the CYA levels climb at least 4 points per week (3 pucks per week in a 25K gal pool), 6 points per week if my CYA started at 20, or 8 points per week if my CYA was at 10. I'm going with a starting CYA of 20, for 6 points a week.
If my season on Long Island is 3 months long (13 weeks) this means I would be adding 78 points of CYA If I relied only on Trichlor from opening to closing. That level is probably tolerable, but toward the end of the season may be begging for trouble. If the CYA is lost over the winter and goes to 0 (I opened my pool it was probably 0) this would clearly make exclusively using the Trichlor pucks feasible where I am. I have to say that this last several weeks was easy peasy. Checked the FC and pH about 3 times a week, Kept the equivalent of about 3 pucks in the chlorinator and the FC was quite constant.
Now I'll probably need even more FC than before since the CYA levels are up. So an FC of 2 (as the pool has settled into) might not cut the mustard from here on in. Time to supplement with a little liquid chlorine, the after another week get off the pucks altogether.
UPDATE ON SAND FLITER It seems that the flow of sand has stemmed, so I'll chalk up my sand issue to the new installation.
GOT A DOLPHIN POOL ROBOT. I don't love it unconditionally, I think it doesn't spend enough time in the shallow end, or climbing the walls. I am not alone, this is the primary complaint from other owners. But it is better than the alternative of me not getting around to doing a proper pool vacuuming, so I think I'll live with it. Maybe it will grow on me a bit more with time.