I ran into a perfect storm of a sanitation challenge (nightmare) a few weeks ago—faulty CYA measures (65+ instead of 35ish - Pentair CYA test tablets), pump motor died, questionable bleach strength—resulting in a pool the color of a kale/spinach smoothie. One and two have been solved and three is why I'm here.
With new TFP CYA and FAS-DPD kits I have observed that the liquid bleach I used to use seems to be about half its rated strength (6%). This is the third time in 9 years I have had to deal with a pool sanitation issue. The bleach I have always used worked in getting me through to a sparkling, clear pool. This time I was adding endless quantities of bleach with very minor results and running through a lot of reagent for tests (difficult and costly to import to Nicaragua). Given the quantities of bleach and test reagents I was going through, I lowered the CYA to a more slam and test reagent friendly level. Running low on CYA test reagents I followed the chlorine strength test given in this post by CRG_80cc in 2007.
Just to confirm that am I doing it correctly: two 100ml glasses of demineralizes battery water; remove 1 ml water from one, replace with 1 ml bleach, mix; remove 1 ml water from second, replace with one 1ml of water/bleach mixture from first, mix; test using FAS-DPD; each drop equals a .5% concentration of bleach (12 drops should = 6%).
I have tested bleach from three vendors and arrive at the same results. What should be 6% (12 drops) is showing 3ish% (6-8 drops). It could be that all three are using the same distributor/source. Regardless, the increased cost and unreliability are a problem.
One option is to buy bleach from an industrial supply/manufacturer that caters to the mining industry. The bleach is 33%. I recall seeing in other posts that concentrations this high will bleach out the FAS-DPD reagents (if used directly in tests). Can I dilute this down to 10/12% or 5/6% for testing purposes? And, if I buy this in 10 gallon barrels, how stable is it over a month or two that it would take to go through it?
Oops. Got my Spanish cloridrico (muriatic acid) and hypoclorito (bleach) confused. Not an option.
My only other option is to resort to tablets and monitor the CYA. Tablets have been the only means of adding CYA in the past and bleach concentrations while doing so have been very accurate. Tablets are also very much cheaper than the amount of bleach I currently have to buy. Hate to do it. Not very TFPy.
Thanks for reading and any suggestions, thoughts.
Alan
With new TFP CYA and FAS-DPD kits I have observed that the liquid bleach I used to use seems to be about half its rated strength (6%). This is the third time in 9 years I have had to deal with a pool sanitation issue. The bleach I have always used worked in getting me through to a sparkling, clear pool. This time I was adding endless quantities of bleach with very minor results and running through a lot of reagent for tests (difficult and costly to import to Nicaragua). Given the quantities of bleach and test reagents I was going through, I lowered the CYA to a more slam and test reagent friendly level. Running low on CYA test reagents I followed the chlorine strength test given in this post by CRG_80cc in 2007.
Just to confirm that am I doing it correctly: two 100ml glasses of demineralizes battery water; remove 1 ml water from one, replace with 1 ml bleach, mix; remove 1 ml water from second, replace with one 1ml of water/bleach mixture from first, mix; test using FAS-DPD; each drop equals a .5% concentration of bleach (12 drops should = 6%).
I have tested bleach from three vendors and arrive at the same results. What should be 6% (12 drops) is showing 3ish% (6-8 drops). It could be that all three are using the same distributor/source. Regardless, the increased cost and unreliability are a problem.
Oops. Got my Spanish cloridrico (muriatic acid) and hypoclorito (bleach) confused. Not an option.
My only other option is to resort to tablets and monitor the CYA. Tablets have been the only means of adding CYA in the past and bleach concentrations while doing so have been very accurate. Tablets are also very much cheaper than the amount of bleach I currently have to buy. Hate to do it. Not very TFPy.
Thanks for reading and any suggestions, thoughts.
Alan
Last edited:
