High FC vs Phosphate testing

[TCP007]

Hello:

I was hoping to close the pool this weekend. I super-chlorinated over a week ago (I usually do before closing), but now that I have my Taylor K2006... I'm testing more accurately, and wondering what the pro's might advise me to do.

FC = 15
CC = 0
pH = 7.5
CYA = 40 < 50

This week, I purchased a Taylor K1106 Phosphate test kit. My phosphate level is approx. 375ppb. I have some PhosFree and intend to add the recommended dose before shutting down for the winter.

2 questions:

1) The K1106 instructions didn't say anything about chlorine levels prior to testing. After I tested, I was reading the dosage amounts on the PhosFree bottle and noticed it recommends testing when chlorine levels are below 5ppm. Is my Phosphate result skewed due to my FC being so high?

2) Do I need to worry about closing my in-ground, gunite pool with this high FC result? Pool is 35,000 gallons. I use a mesh winter cover.

I'm able to put winter cover on and delay lowering pool level for the time being if needed.

Thanks for sharing any concerns.

[CarlD]

If your pool is clear, no sign of algae, with YOUR numbers you can and should stop wasting your money on phosphate removal. Phosphates are food for algae, no more. Many of us have fairly high phosphate levels (if we bother to test for it at all--I never have) and STILL have perfectly clean and sanitary pools. Phosphate removal DOES have a legitimate place in pool care, but not for 99.99% of us. It's just another revenue-generating scheme.

Furthermore, we've found that in the rare case where it's appropriate (persistent, tough mustard algae) the EFFECTIVE level of phosphates is far, far lower than the levels the pool stores tell you.

[TCP007]

Hey Carl... thanks for the advice.

After the kids started school (3 wks ago), I did had some algae start growing in spots on the walls and corner walls, and the water clouded up a little... but not terrible. My FC was never below 7ppm since superchlorinating back in July, and aside from the trichlor in my floater, I was told to hold off adding more sanitizer (I use dichlor) until the FC was down to at least 5ppm. My CC was 0, CYA has been steady at 40, pH 7.2 to 7.4, and I typically toss in 4 oz of algaecide weekly for ****s and giggles. With my levels all seemingly good; I started thinking about what else could be feeding this problem? I had read about the phosphate test/levels in my Taylor manual, so nobody sold me on it aside from Taylor. We got some regular rain here in MI a few weeks ago, and I read that'll boost phosphate levels. I thought the mods here recommended Taylor, but I see you're calling BS on the Phosphate test. I should say, worrying about phosphate levels that is.

I'm all for that... I just don't get what started tripping me up?

Thanks again, Carl. If you have more to add... please do. If not, I appreciate the advice and I'm all for not spending on anything unnecessary! Have a great weekend-

Maybe it's just the inaction of the pool then? My pump runs 24/7, too. I give up.

[chem geek]

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

So I very much doubt that your "CYA has been steady at 40". Are you sure you are measuring the CYA correctly? Pool store tests for it can be inaccurate.

Either your CYA level is higher than you think or you've got poor circulation in the areas of algae or you've got yellow/mustard algae instead of ordinary green algae. Even with yellow/mustard algae, an FC that was 15% of the CYA level should prevent it from growing so again your numbers don't make sense, especially the CYA number given your use of (only?) Trichlor and Dichlor.

[CarlD]

Richard, (Chem_geek) knows the chemistry of pools about as well as anyone here, if not better.

Basically, he's saying your pool store sold you a bill of goods. IOW, their advice stinks. We can probably help you more effectively.

[TCP007]

Carl & Richard:

Why do you guys think I go to a pool store? I don't have a pool store in my town, and nobody has sold me on anything. Not sure what I said to get that type of response (?) but it's just me, myself and I here in SW Michigan. As my original post states, I use the Taylor K2006 for my testing. I also posted my CYA was between 40 and 50, but it's not above 50. Seeing the "black dot" disappear is certainly subjective, but my eyes aren't THAT bad. Not sure what any of that has to do with my original post, but wanted to respond. Thanks for the help.