Free Chlorine Too High And Not Burning Off

[hgregs]

hi all...

i have a vinyl pool with an aqua-rite chlorine generator. i do not have a cover.

pool temp is 80-88deg.

last saturday i noticed that free chlorine reading was >5ppm (i have a dpd test kit, and the FC reading only goes to 5, and i'm much darker red than the #5 color).

i turned my salt-chlorinator down to 30%, and checked again on sunday. the reading was again too high, at which point i turned the aqua-rite off completely.

it's now thursday, and i have not turned on the salt-chlorinator, nor have i added chlorine. the reading is still darker than the test kit will measure.

my cynuric acid is 70ppm, which is the middle of the range suggested in the aqua-rite manual.

any ideas what's going on here? do i need to do anything besides wait? how long would i have to wait? is it safe to swim?

greg

[quantumchromodynamics]

Get some distilled water. Test it for chlorine to verify that there is no chlorine in it. Then dilute your pool water 50% with the distilled water. Test the 50/50 mix for chlorine. Double the result. If it is still too high, dilute to 25% and re-test. Multiply result by 4. Post back the results if you need further help.

[hgregs]

thanks for that algebra guidance. that could have taken me forever to figure out.

my FC reading is 10ppm. it's friday 4pm eastern. i'll report back with what it reads tomorrow morning to see if it's going down.

i've read 10ppm is ok to swim in, just not preferred.

greg

[waterbear]

With a CYA of 70 ppm you can swim in much higher than 10ppm.

I would suggest getting a test kit that uses the FAS-DPD titration test for chlorine. It's much easier than color matching and can test up to 50 ppm FC with a precision as great as .2 ppm. If you currently have a Taylor K-2005 kit then you can order just the FAS-DPD test from Taylor. If you have any other test kit do yourself a favor and get a Taylor K-2006, which includes the FAS-DPD test and al the other tests you need except for salt.

[quantumchromodynamics]

http://www.taylortechnologies.com/slide_sh...SDPD/index.html

http://www.taylortechnologies.com/images/j...5_A_500x375.jpg

http://www.taylortechnologies.com/products...&KitID=2185

[hgregs]

thanks for the replies...

9am - measured FC at 15ppm (i could have been off in my "reading pink" yesterday - the difference b/t a 2 and 3 reading is multiplied by 5). CC=0.

the SWG has been off all week. but the filter pump runs 24/7. is there any chance the SWG is generating chlorine even when the aqua-rite control board is set to "off?" do i just keep it off for now?

given my CYA at 70ppm, does that mean i should target 7ppm FC?

is there a chance that with CYA so high, the FC just doesn't burn off at a normal rate?

i have an 8mos old daughter that we like to take swimming, and we haven't had her in the pool since the FC readings were so high. is it safe to bring her in now? (her head stays above water)

greg

ps... this is my test kit. looks like it was relabled

http://www.lesliespool.com/browse/Home/Wat...:400000/I/81330

[hgregs]

on the back of the aqua-rite manual, they say FC should be 1-3ppm, and CYA 60-80ppm. from reading around these forums, i would assume most around here would disagree?

[PaulR]

The CYA sounds about right, but the FC really shouldn't go below 3 even with a SWG.

--paulr

[hgregs]

2pm, sun shining bright, FC = 15, TC = 0.5 - 1

thoughts?

[waterbear]

2pm, sun shining bright, FC = 15, TC = 0.5 - 1

thoughts?

If you have over .5 ppm CC then you need to shock to get rid of it. I would shock to about 25ppm and then wait for the FC to drop below 15ppm and go swimming.

[quantumchromodynamics]

As WaterBear had noted earlier, you will get much better and more reliable test results with the

FAS-DPD Test

[hgregs]

thanks for the help. with the fas-dpd test, i now read 7ppm FC and no CC. the SWG has been off for 2 weeks. this seems ideal. i'll plan to turn the SWG back on when i go below 5ppm, or when my CC is higher than breakeven (unless i hear otherwise).

[quantumchromodynamics]

Sounds good. I have to say that I find it amazing that your pool can go for such a long time without losing chlorine.

[hgregs]

4 days later, FC of 2.5ppm, and no CC. i finally turned the SWG back on.

[billp]

You did not say how big the pool is, but if we assume "average" then it would be very easy to overchlorinate with the pump running 24/7. Unless you have a 1/4 hp pump I see no reason to run 24/7.

The main problem is you need to test the water more often and adjust the output so you stay within the desired range. Unless there is heavy pool usage a warm weather range of 2-3 ppm Cl usually suffices and 1-2 ppm in cold weather.

I didn't trust your original CC reading and turns out it wasn't good. It would be unusual to have any CC with the original high Cl level you had.

With high Cl you can wait or you can add Cl neutralizer. Whichever best suits your needs and budget...

[PaulR]

Unless you have a 1/4 hp pump I see no reason to run 24/7.

Or if you have a two-speed, run it on low 24/7.

--paulr