Hopefully...minor clarity issue

[buki5]

Thanks Watermom.

One difference from today to tomorrow is that I will cover the pool (power cover). I just did a calc. and I show that adding 2.84 gal (2 bottles) would take me up to a little over 11.....

I can go more but want to be able to use the pool tomorrow (or any day for that matter) and am concerned about everyone swimming with too high a chlorine level. My wife wants me to talk to the "Experts"....I've been holding her at bay. Of course I don't want the algae to return either.

As for the CYA. I'll do a drain but want to get a few days in first. I do have a nice stockpile of bleach .

[Watermom]

I deleted your other post with the incorrect numbers. BTW -- when you realize soon after you make a post that you need to correct something, instead of posting another post, you can go in and EDIT it. Just click on the blue edit button in the lower right corner of the post. There is a time frame where you can do this, but I can't remember how long it is.

[buki5]

So, I think my basic question is what is my chlorine level range where everyone is able to swim and Algae is being held off (water clear)?

8-10 or 8-something higher? I believe I've seen on here at my CYA levels I need to stay at 8 or above to keep algae at bay? But how high is still safe for swimming?

[Watermom]

Take a look at this version of the "best Guess CYA chart." You must maintain cl between 8-15 all the time with your cya level. Swimming in a higher chlorine level pool is less of an issue if the cya is also high. I don't think there is a magical "cut-off" number. But, I'd probably wear an old swimsuit.

http://www.poolforum.com/pf2/faq.php...aq_bg_chlorine

[buki5]

Perfect. Thanks. I've referred to the Best guess table a number of times. So, I think I can do that. And yes will likely drain sooner rather than later....then I get to start the chemistry all over again.

[Watermom]

then I get to start the chemistry all over again.

We'll be in your back pocket helping then, too! Have fun swimming this weekend!

[chem geek]

Losing more than 50% of the FC in a day with a very high CYA level means you've got more than just loss from sunlight. You could check the overnight chlorine loss, but I suspect you've got nascent algae growth even if it isn't visible -- again, if the CYA reading is truly as high as reported.

Usually even in very hot sunny weather the chlorine loss will be around 15% in a day when the CYA is 100 ppm or so. At 60-80 ppm it may be around 20-25% FC drop while at 40-50 ppm it may be up to 50% and at 20-30 ppm it could be up to 60%. Higher CYA levels have lower chlorine loss rates even when proportionately keeping the FC higher. It may have to do with some direct CYA shielding effect protecting lower depths from sunlight.

[buki5]

Thanks again all.

I've been testing CL levels at least 2 times a day to understand what is happening. The run down of the last 20 hours or so is this. Weather is Sunny and warm.

Last night added the extra bleach suggested by Watermom. I was at 11.05 plus another bottle which should have taken me to around 14.5. Checked this morning before work (left pool open overnight) and measured around 14. Covered the pool for the day, came home and measured again (about 11 hours) and got a 12.5. Kids swam, dog swam, I swam (2.5 hours passed, I checked CL again and measured 8.5. Added 2.84 gal 6% and leaving open overnight. Will measure before I go to bed later and expect a 14.5 to 15 reading. Will check again in the morning. My money says it will be in range of 13 to 13.5 then when I get home am expecting around 11.

Will keep you posted.

[Watermom]

Sounds like you are getting control of this pool! I still think, if it were me, that I would do a partial drain and refill, but glad you are getting to swim some. After all, that is what having a pool is all about! Have a great weekend!

[buki5]

Couple more things...
Do I understand correctly that the belief of the BBB method is that you only need to shock if you are having or starting an algae or known pathogen problem? I'm referring to the PS statement of shocking weekly?

Also, RE: CYA testing I've tested using the add 7oz water then add 7oz regent shake like hell then drop until you can't see the black dot enough to go through a little over 2 bottles (.75oz) of regent. Every single time I don't get half way to the 100 mark before I can't see the dot. basically the fluid drops out almost white. The first couple of times I thought for sure I was doing something wrong but in reading I haven't seen anything to have me do any different and my tests have been consistent.

For background this is a pool with a power cover and the Pentair 300 3" tab chlorinator adn when I moved in the valve on the Pentair was set at the max setting. I wouldn't be surprised if the majority of the water is years old and the prior owners were struggling to keep the water clear. Based on what I'm seeing on here Regarding the tabs I'm not real surprised...now. (although I was the first few times).

Brian