Chlorine problems...... help

[trainguy]

I've had the pool for 3 yrs now and have not had a problem up until this year. I opened in the usual way, water was clear, added chlorine, bought chemical levels up to where they should be, added chlorine, checked again, added chlorine, checked, added chlorine........... I've added about five gals of liquid and six pounds of powder to 10,000 gals and still can't get more than a yellow reading on the test strips. I was told that the test strips could be old even though they were still in date, so I bought new test strips. Still no chlorine reading. All other readings are exactly in the range they should be in , including the "PH". So does anyone have any new ideas as to what I'm doing wrong????? It's the end of July and I'm running out of summer. lol Please help!!!! Thanks trainguy

[yacahuma]

In my little experience, test strips just dont work. I will suggest getting a test kit to start. And re test your pool

[RMS1]

Get a good DPD test kit, not OTO. and check the cyanuric acid level, should be between 50-70. If it's too low your chlorine in ineffective.

http://clean-pool-and-spa.com/index.html

[chem geek]

Even better than a DPD chlorine test is a FAS-DPD chlorine test. The reason is that the DPD test will bleach out above 5 ppm FC and though you could use dilution to get around that, it won't be as accurate. For every day testing even OTO can be OK, but when you need to know overnight chlorine drops or when you need to test levels during shocking, the FAS-DPD is best. See a demo of it here.

For an overall test kit including the FAS-DPD chlorine test, I suggest either the Taylor K-2006 you can get at a good online price here or the TF100 from tftestkits.net here with the latter kit having 36% more volume of reagents so is less expensive per test.

As for Cyanuric Acid (CYA), it is not true that if the CYA is too low the chlorine isn't effective; quite the opposite. If it's too low, then chlorine will break down faster in direct sunlight, but at a given FC level the chlorine is MORE effective. Higher CYA levels require proportionately higher FC levels to have the same amount of active chlorine (hypochlorous acid). High CYA levels make the same FC level LESS effective. All of this is known science since before 1974 but was definitively determined then as described in this paper. I have many links to scientific studies showing the reduction in chlorine effectiveness at higher CYA in this post.