Weird test results

Hello,

I found this site last year and it helped greatly with my inground pool. I use a Taylor 2006c testing kit. I just openned my pool last week. It was crystal clear and readings were: FC- 2.5 CC-0 ph 7.6 and stabilizer was 50. All great numbers except chlorine, which I added. Fast forward a few days and I noticed I was getting a cc reading of < .5 which of course tells me that I am battling something. Pool still looks crystal clear but I raised FC to around 20 and have been holding it there for two days or so. I am still getting a cc reading of < .5 and my FC numbers drop significantly and quickly. For example, at 9 AM this morning my FC was 20.5 so I added a gallon of 12.5 % chlorine. I tested the water at 1:30 PM just now and it read FC 15.5! It dropped 8-11 ppm in like 4 hrs??? Is that possible? It is a cloudy rainy day here so sun burn off should be negligible. The cc reading still shows < .5. I am using last years chemiclas and they were stored in my garage over the winter, and it's possible they froze. Maybe my chemicals and no good??? Please help...

Yeah, I think your reagents are shot. I would order replacement for all of them--you can hold off on the calcium stuff because you don't need it with vinyl. If there is a Leslies nearby they usually stop most, but not all of the chems. You probably won't get the FAS/DPD reagents, nor a large bottle of R 13 (CYA reagent).

I store my test kits indoors winter and summer and rarely have a reagent failure.

Keep in mind that clouds don't block UV light much. I've had many a sunburn to prove that is true. Dose chlorine at sundown and then retest before sunup the next day and see where you end up.

Well I have kept my FC over 20 for at least 3 straight days but am still registering a cc of < .5 each time I test. The water looks crystal clear but I am still losing FC at a rapid rate. Tonight I will test after sundown and before sunrise tomorrow to see what the loss is overnight, but I won't really know until my new reagents arrive in the mail...GRRRRRR.

Ok, so I used a friends test reagents and found that I am losing about 6-7 ppm from sundown to sun up the following day. I am still getting a < .5 cc reading also. My water looks crystal clear, but these numbers seem to indicate I am battling something. Is it possible that my cartridge in my filter is harboring some unseen stuff that I havent been able to kill?? I have had my pool at above 20 ppm chlorine for three days straight (shock level) and am still getting huge chlorine losses overnight and during the day. Any insight would be helpful.