Stabilizer too high - safe to swim?

[georgia]

Lost my mind 1 month ago and added 5 lbs cyanuric acid (stabilizer) to my 20K in-ground pool with a 80 ppm reading.

Tested yesterday and now at 110 ppm. Looked over notes from last month and have no (Corona) idea why I would do that.

In any case, can't seem to find any where that says positively that the pool is or is not safe to swim in.

Any one know for sure?

My plan - unless unsafe to swim - is to just let evaporation and refills solve the problem. New Aquarite chlorine generator can handle it.

Thanks!
Mike in Georgia

[Guest]

It is safe to swim in if you keep chlorine levels higher than normal. The cyanuric acid is not harmful itself. A free chlorine level of about 8 would be right for that level of cyanuric acid, if I'm remembering correctly.

Your CYA level won't go down through evaporation. Only from backwashing, draining or splash out.

[muss08]

FC should be at 11 with your CYA at 110 or 8.5 if you are using a poly 60 algaecide. As previously stated cyanuric acid is not harmful and dilution is your solution for lowering- evaporation and refilling will slowly get it down.

[georgia]

First, thanks for the replies.

Second, if I understand correctly, I "make" the "free chlorine" increase by super chlorinating with my Aquarite chlorinator. Which about once a week or following a big rain seems to work fine.

However, I would think if I super chlorinate frequently or long enough to bring up my FC between 8 and 11, my normal chlorine reading (2 to 3 ppm) would be off the chart and I'd be afraid to let the kids swim.

Am I mistaken or you're both saying because my CYA is 110, I won't go off the chart.

Thanks!

[chem geek]

The Free Chlorine (FC) measurement may be beyond what your test kit can measure (some only go up to 5). You should get yourself a good test kit, such as the Taylor K-2006 kit you can get for a good online price here or the TF100 test kit from tftestkits(dot)com here with the latter having 36% more volume of reagents so comparable in price "per test". The FAS-DPD chlorine test in these kits has a resolution of 0.2 or 0.5 ppm depending on sample size and can measure up to 50 ppm FC.

The actual disinfecting and oxidizing chlorine (hypochlorous acid) level is roughly proportional to the ratio of FC to CYA. So at a high CYA level, a higher FC is not unsafe nor harsher on the skin, hair, swimsuits, etc. In fact, an FC of 10 with a CYA of 110 is technically equivalent to an FC of 3 ppm with a CYA of 30 or to an FC of 0.08 ppm with no CYA. It is far, far lower than the 1-2 ppm FC with no CYA found in most indoor pools (which are in a sense over-chlorinated).

The only issue with a high FC is that you do not want to drink a lot of the water though it would still take a lot of water to drink over an extended period of time before that became an issue (and one does not normally drink the pool water -- I don't mean just gulps children sometimes do, but full drinking of quarts).

As for raising the FC level initially, you can use chlorinating liquid or unscented bleach. It is harder on your SWG cell if you use it to superchlorinate (it's not a disaster -- it just shortens its life if you do it frequently).

If you do not want to maintain the higher FC so that it is roughly 10% of the CYA level, then you need to use an algaecide to prevent algae such as PolyQuat 60 or a phosphate remover. However, maintaining a higher FC level is the least expensive approach.

Richard

[georgia]

Richard:

You helped me in Oct 07 and at that time I purchased a TF100 kit. It's great and I've not been to the pool store for 8 months.

Understand about maintaining the 10 percent FC - CYA ratio now. Will try with unscented bleach rather than SWG cell as mentioned.

Do you have a link to a calulator that will show FC increase per gallon bleach? Or do you know off hand? Mine is 20k gal. This site has lots of calulators, but not that one.

Will raise the FC level and then just monitor it over the summer with fill and rain, eventually getting it down to 40 ppm range.

Thanks again,
Mike in Georgia

[chem geek]

You can use The Pool Calculator. One gallon of 6% bleach will raise the FC by 3.1 ppm in your 20,000 gallon pool. However, bleach is usually sold in 96-ounce (3/4 gallon) jugs so would raise the FC by 2.3 ppm. They are also sold in 1.5 gallon containers which would raise the FC by 4.6 ppm.

[georgia]

Ok, Richard.

Thanks for the caculator link.

Somehow I had missed that one, which after seeing, is just about everything an amature pool guy could possibly need.

Hope you and yours have a great Memorial Day. Weather here should be ok and pool temp is 88. Ribs, etc., are in the fridge...

Later and thanks!
Mike in Georgia

[willie buchanan]

ph 7.2 free chlorine 3 total alkalinity 120 ppm stabilizer 300 how ?

pool size 7mtr x 3.5 mtrs.

[Ray]

ph 7.2 free chlorine 3 total alkalinity 120 ppm stabilizer 300 how ?

30000 gl pool size.