Really sounds like calcium. Take a small sample and put it in a little white vinegar. If it dissolves and bubbles, thats what it is.

Quit using Cal-Hypo for shocking or chlorine boosts. Use bleach.

I assume PaP is Pinch A Penny. They aren't national but get enough mentions that I knew who you meant.

Scott

It is probably what we refer to as salt cell dandruff.
Usually see it in areas where water is harder. You get build up on the cell, then it self cleans and the flakes are the result.

I will try the vinegar bit. But it isnt building up on anyhting, just laying in the pool. I dont shock my pool at all and have never used anyhtign called Cal-Hypo. Yes I mean Pinch a Penny.

just a pb - this makes alot of sense. It looks like the stuff that is built up on the blades in the past when I cleaned it. I did check the salt cell recently and it was clean.

I hope that is what it is, otherwise I have no idea and no one else seems to either.

Last night, rather than vac them, I netted them out of the pool and dumped them, so we'll see if they return. thanks

flchad,
Sounds like calcium carbonate. Usually occurrs when the ph rises. Adjust ph to the lower portion of the ph range and it should disappear. Try to avoid ph bounce. Add acid daily if necessary. Good luck.

I agree with all above. I had this issue this year too. I got some out, poured acid on it and it bubbled like mad and was gone so it was CA. Dropped my PH for a while and haven't had issue again.

I add about 3 cups of muratic acid a week to my pool. Sometimes I miss a week if I am out of town, but I am constantly fighting the pH rising from my water type as well as the salt cell. However it never gets above the 8.2 range so there are no gross "bouncing" levels.

So I am a little confused now - if it is ph related, where is this stuff coming from that it just lays on the pool bottom. It isnt stuck to anything. I was under the impression calcium carbonate "grew" in the pool so it would be stuck to the finish.

I was hoping it was more the salt cell dandruff.

flchad,
You will get better production/service from your salt cell if the ph remains between 7.4-7.6. 8.2 may not seem like a big change, but it is.
You might check other water chemistry items such as Total Alkalinity. If TA is high you will also have trouble keeping the ph in check.
When Salt Generators first became popular in the early 90's I used to put different brands on my pool and then do everything I could to cause the unit to fail. All of the cell units produce the flake you describe when the ph is over 8. Manufacturers still have a ways to go to produce a cell with reasonable longevity. IMO a cell should be expected to last more than 4 years on average. Most who purchase a Salt Gen. will spend $2000 on the unit in 4-5 years including purchase price.

Thanks again for all the info. I am going to keep a better eye on the ph now as well as CH and the alk.

I guess one bottom line question I havent asked: is there any harm to the pool to come from these flakes, especially any harm to the finish?

I had the same thing the whole time I used a pool service - my PH was usually closer to 8.2, I've discovered if I keep mine closer to 7.6 I have no calcium dandruff, as soon as it goes over 8 it appears within a day or so. I add acid a couple times a week now and aim for the lower end (between 7.2 and 7.6) - everything runs much more smoothly.

We have the same problem... We build new house last year...Our pool builder Intercoastal Pool and Spa in Melbourne, Fl said it was salt dandruff and that Pentair intellichlor is pre-disposed to salt dandruff...However Pentair told us it's not the chlorinator but it's a combination of pH being too high and alkninitity being off... Long story short... a local pool store suggested using product called Jack's Magic Magenta Stuff http://www.jacksmagic.com/products/JMMAGENTA032.html It worked.... we have 18,000 pool and one quart worked..first vacuum up "dranduff"...then pour in whole bottle. I"m going to start adding about 5 oz's weekly of it to see if it will prevent dandruff from coming back.... When I first used the product it kept it at bay for about 3 months... Good luck.

Always adjust your Total Alkalinity before adjusting your Ph. Otherwise, you will be chasing the Ph around in circles. You do not need Jack's Magic Stuff. Just buy some Baking Soda for your buffer. Go to poolcalculator.com to find out how much you need.