Testing chlorine at higher ppm than the test kit is capable?

mstriker · May 20, 2008

Right now I have a HTH test kit (not in the budget to get a Taylor kit, as much as I would like one)
Is there a way I can test for higher chlorine amounts through diluting the sample?
HTH says use 5 drops of the reagent

one otherthing do these reagents have a shelflife?

Thanks for any help

lovingHDTV · May 20, 2008

If you dilute the pool water sample with distilled water you will double the testing range. At the same time you double the error, but at least you can get an idea as to your chlorine level.

I've always heard that you should replace your reagents yearly.

JohnT · May 20, 2008

Yes you can. You lose some accuracy, but when you are shocking it's not a huge deal. Mix the pool water sample with three parts distilled water, and then you test the mixture. Multiply the result by four.

The reagents have a shelf-life, but if they are stored at reasonable temperatures out of the light, they last a long while. I found a test kit with an expiration date of 1996 last summer, and the results were indistinguishable from my TF-100. The reagents had been in a box in the basement since 1998.

kirbinster · May 20, 2008

Why not just put one drop in and multiply by 5 or put two drops in and multiply by 2.5 to estimate your reading.

JasonLion · May 20, 2008

Varying the number of drops changes the visibility of the color but it doesn't change which color it matches on the color standard. Or to put it another way, fewer drops makes it more difficult to read, but gives the same answer as the usual number of drops.

kirbinster · May 20, 2008

WOW, so you mean you are not doing a titration and the number of drops really don't matter?

ChrisL · May 20, 2008

I just realized that what I said might not be accurate so I deleted it..

JasonLion · May 20, 2008

kirbinster said:
WOW, so you mean you are not doing a titration and the number of drops really don't matter?

The test under discussion isn't a titration, it is matching against a color standard. When doing a titration you count drops till the color changes. When matching against a color standard you add indicator and then compare the color of the water to the color standard. For a titration the number of drops matters a great deal. For comparing to a color standard the number of drops doesn't really matter, it is just a convenient number to make the color easy to see.