Testing pH, AL, CH with high CL

[catnip]

My WalMart AquaChem test kit say not to test for pH, TA or CH unless "total available chlorine" in 3.0 ppm or less. Does this apply even if CYA is present?

[fcfrey]

Unfortunately the answer is yes for pH. Chlorine will bleach out the result. You can add a drop or two of Sodium Thiosulfate (before you add the phenol red) (that is the R-0007 reagent in the TA test) to kill the chlorine but it may alter the results slightly.

The only good alternative is an electronic tester but the probes need calibrated and replaced periodically.

EDIT: Order Ben's kit ---- he has the chemicals sized for the test so you don't run out of the first reagent before the second.

I wish I had done this --- I have bought 6 different kits from taylor which cost a Whole lot more

[duraleigh]

The only good alternative is an electronic tester but the probes need calibrated and replaced periodically.

Am I missing something? What about Ben's Kit?

[catnip]

fcfrey, thanks. I was afraid of that. I do have Ben's kit on order...still waiting.

The good news about the AquaChem kit is that they will sent you a complete refill set free...just by calling and requesting.

[Simmons99]

Actually - the PH test is probably okay for any chlorine level under 10ppm. I have my chlorine level at 4~6ppm and the PH test is the same as when the chlorine has dropped to 1ppm.

[chemistrydropout]

fcfrey, thanks. I was afraid of that. I do have Ben's kit on order...still waiting.

The good news about the AquaChem kit is that they will sent you a complete refill set free...just by calling and requesting.

Good luck my Aqua-chem refill has been on order since Aug 21 and I still haven't seen it in the mail. I need some reagent for my cya. They said they would just send a complete refill kit all three times I have called. Others have had better luck from what I've read on the forum. Mr Murphy just has a way of making things like this for me every time.

[catnip]

AquaChem told me to expect delivery in three weeks...so we'll see.

[aylad]

Ben's dpd/fas test for chlorine will accurately test for Cl up to 50 ppm, whether or not CYA is present. It is a good, accurate alternative to the OTO tests.

Janet

[fcfrey]

Catnip --- Your original question concerned the accuracy of the pH test when the Cl is above 3.0 ppm.
My answer is based on my experience. Yes it does bleach out using phenol red pH test.
I'm not sure what pH method is in Ben's kit, as I said I have a menagerie of Taylor kits (that's what happens if you don't get educated here first).
I have had electronic testers and sent them all back, because I didn't see a significant difference when adding a drop or two of thiosulphate and didn't want to spend te extra money.
Ben's kit does include the FAS-DPD method for Chlorine which is a much better test than the standard DPD method (using colorimetric comparison). The FAS-DPD test has a definite end point and is capable of testing high levels of Cl.

Hope that clears up my original answer.

Again Ben's kit is a great value for the complete package. Like I said before my Taylor menagerie cost me well over $300.00 combined (too soon old --- too late Smart)

[catnip]

fcfrey, yes it does. Thanks.