Chlorine test

[dave]

[code][/code] how do you test Free Chlorine and Combined Chlorine? I use the OTO test that turns the water yellow I guess that is the CC how do I test for the FC

[chem geek]

You cannot use the OTO test for anything but Total Chlorine and even then it's only very approximate. You should instead use at least the DPD test, but better than that would be the FAS-DPD chlorine test since this measures to within 0.2 ppm (or 0.5 ppm depending on sample size) and can measure up to 50 ppm whereas the standard DPD test bleaches out above 10 ppm. The FAS-DPD can accurately measure FC and CC.

So please do yourself a favor and get the Taylor K-2006 at a good online price here or the TF100 from tftestkits.net here with the latter kit having 36% more volume of reagent so is less expensive per test.

[dave]

the problem i am having is that i have a automatic chlorinator and I have it set at 0 and I am still getting a high chlorine reading. There has been no sun here in upstate N.Y. for 4-5 days now and My solar cover is on. Is it just that there is nothing in the pool for the chlorine to work on and the sun is not cooking it off?

[chem geek]

Yes, without sunlight to break down chlorine, it will only slowly dissipate, especially with the cover on. The chlorine demand is likely to be around 0.5 to 1.0 ppm FC per day so the drop will be slow. If you've been using an automatic chlorinator with Trichlor pucks/tabs, then the Cyanuric Acid (CYA) level is likely to be high so a high FC is not a problem and in fact is often necessary to prevent algae growth. Read the Pool School for more info on how to maintain a pool, on good test kits, etc.

[Terry]

[code][/code] how do you test Free Chlorine and Combined Chlorine? I use the OTO test that turns the water yellow I guess that is the CC how do I test for the FC

hi i've just been to visit a friend in France and helped to do a chlorine test using a tester with liquid drops. the colour of the test liquid was almost amber / orange and was much brighter than any of the colours on the testers scale. the pool has been 'opened' by the original supplier and there are chlorine tablets visible in the filter baskets. What does this 'bright colour ' indicate please , too much or too little chemical ?

[Denali]

[code][/code] how do you test Free Chlorine and Combined Chlorine? I use the OTO test that turns the water yellow I guess that is the CC how do I test for the FC

hi i've just been to visit a friend in France and helped to do a chlorine test using a tester with liquid drops. the colour of the test liquid was almost amber / orange and was much brighter than any of the colours on the testers scale. the pool has been 'opened' by the original supplier and there are chlorine tablets visible in the filter baskets. What does this 'bright colour ' indicate please , too much or too little chemical ?

If using the OTO test then it would indicate a high chlorine level. It won't tell you how high or what part of it is FC, only TC.

[Terry]

I think from what you say it must be the OTO test, I'm not sure but will look at the kit when I'm next there in July. If it was the OTO test then as you say it must indicate a high level, that said, there was no smell of chlorine in the water/ air or swimming garments so iguess it didn't have an excessively high chlorine content , am I right. Is the the best solution to get a DPD test kit ? and re try ? thx terry

[chem geek]

I'm sure it was an OTO chlorine test since that goes from yellow to amber to orange to red as chlorine gets very high. The DPD chorine test which gets pink/red will bleach out above around 10 ppm FC (and isn't accurate above 5 ppm) so isn't the best to use either, though at least it will measure FC and CC. The best to get is the FAS-DPD chlorine test such as found in the Taylor K-2006 you can get at a good onine price here or the TF100 kit from tftestkits.net here with the latter kit having 36% more volume of reagents so is less expensive per test.

With the FAS-DPD chlorine test, you can measure Free Chlorine (FC) and Combined Chlorine (CC) separately and accurately to within 0.2 ppm when using a 25 ml sample or 0.5 ppm when using a 10 ml sample and can measure up to 50 ppm.

[Denali]

I think from what you say it must be the OTO test, I'm not sure but will look at the kit when I'm next there in July. If it was the OTO test then as you say it must indicate a high level, that said, there was no smell of chlorine in the water/ air or swimming garments so iguess it didn't have an excessively high chlorine content , am I right. Is the the best solution to get a DPD test kit ? and re try ? thx terry

High free chlorine levels don't give you the chlorine smell. The smell comes from combined chlorine which means you need more chlorine. So if you aren't smelling the chlorine that's a good thing.

[Terry]

Thanks all, you've improved my knowledge enormously. i'll get a kit to test for FC & CC and let you know progress. Thx Terry