Hi!
I have read that the OTO is the most reliable test yet have not tried it.
It is a 'bulletproof' test in that it will show you chlorine if any is there and not bleach out. It's downside is that it only tests total chlorine and will also register MPS (and other oxidizers). It is useful for a quick daily check of chlorine levels when you don't want to break out the 'big kit" (as long as you are doing a full set of tests weekly or as needed.)
I purchased the FAS DPD test I believe 2 years ago from Ben (??) or someone else who writes on this forum as it came highly recommended. The problems I have with this test is that the black granules once dissolved cling like gum to the side of the plastic vial and cannot be removed without serious scrubbing. This started last summer. Also, I have to add a lot more granules to make the water turn pink. The water never turns back to clear rather stays grayish dull in color while adding the reagent which I suspect is from the gummy residue.
YOUR REAGENT HAS GONE BAD. THROW IT OUT AND BUY NEW DPD POWDER!. The Taylor DPD powder R-0870 is exactly the same as the DPD powder Ben had in his kit. DPD powder should not be black. It meand it has oxidized. It really should be white to grey. Once it starts turning black, while possibly usable, will have the side effects you mentioned.
Although I know I added enough bleach to have 31ppm Cl in my pool the other day, I could not verify with this test. So..... I am wondering if anyone else has experienced this problem with this product. I keep my pool kits in the pantry closet where the humidity is less than 60% and temp under 80. I think most chems have atleast a 2 year expiration so eventhough I have granules left I need to order something new.
Would it be better to buy the OTO? If not, is the Taylor product good or is there another brand I should try?
IF you want to pick up an inexpensive OT kit to use as a daily tester then get a Taylor K-1000 OTO/pH test kit. It is well under $10 but it will NOT replace your FAS-DPD test kit.
Oh, also, while I am thinking about it, I want to eventually use Borax. What is the best method/reagent to test for borates in the water?
The easiest way is the LaMotte borate test strips. Don't get the AquaChek strips, they are next to useless and impossible to read. If yo have a Taylor K-2006 or K-2005 test kit you can get an add on borate test from Piscines-Apollo Pools in Canada. It is a drops counting titration much like the FAS-DPD test but a bit more complicated and uses two of the reagents in the Taylor kit in addition to the reagents included with this add on
Thanks in advance! I appreciate all the info available on this site. Although I have learned a lot, I believe you can never have a trouble free pool!
I will post another question about Calcium and CYA testing shortly.
( Gunite Pool, somewhat heart shaped, 18 x 40', ~30k gallons, 8.25% Bleach, Polaris 480 Sweeper, HOT Coastal South GA and we are away most of the time, summer 2012 we used pool about 10 times so had to use trichlor which sent CYA over 100)
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