Amazing stabalizer or wacked out test kit?

[slawton]

I went away on vacation for a week and ran my SWG 2 hours each day. I had found for my size pool that was good for a correct reading FC reading.

When I returned, the color tested almost orange using the Basic test kit (K-1000). I decided not to run the SWG for a day or two to allow the level to come back to reality.

Over the course of the next week, I tested the water daily with the basic kit. Each day, the chlorine level tested high (in 5 10 range, at the top color level) but it had returned to yellow from orange. It was just very bright yellow.

Well, it's been almost a week since I have run the SWG and I am still getting consistently high FC readings using the basic kit. Do I simply have amazing CYA or what?

I will say the summer has been cooler, with the pool only in the 72-75 degree level and the solar cover on most of the time. Not alot of swimming here in West Michigan this summer.

So, I finally decided to break out the TF-100 and see what I could see.

Here are my results:

FC 2.0!!! (How can that be?!)
CC 1.5 (Mine usually is around .5)
TC 3.5
pH 7.2 (ish)-maybe just a bit higher like 7.3-7.4 but this isn't a choice on the measuring instrument
T/A 110
CH 100 (vinyl pool)
CYA 65
Temp: 75
Salt: 3,520ppm-just a bit above what is recommended

So, I am confused. My FC with the K-1000 is showing high chlorine consistently yet the TF-100 actually came up low. I don't want to go ahead and run the SWG and see "orange" again with the K-1000!

 

[Bama Rambler]

You should have borken out that TF-100 sooner! Now you're gonna have to shock! :thumbdown: Bummer.

I only use the OTO test as a "yes/no" test. I never trust it to give me an accurate FC level.

 

[slawton]

Am I shocking because of the CC level?

And what did you mean by Yes/No test?

 

[reebok]

yeah cc's greater than .5 means shock.
yes/no test means if it turns yellow you have chlorine, it it's clear you don't. but no measurements beyond that.

 

[Ohm_Boy]

Yeah, the OTO test (the yellow one) doesn't really know how to tell FC from CC, so it just shows the presence of chlorine in some form. It's also pretty tough to tell the difference among any levels above 2 with that test. Mostly it is used as a 'yes-no', 'go or no go', 'have or have not', etc. indicator.
Naturally, the FAS-DPD is much more accurate.

 

[anonapersona]

Would the CCs go down if he simply left the cover off for a few sunny days?

 

[JasonLion]

The OTO test in the K-1000 reads TC, which is FC+CC. Since your TC level is 3.5, the OTO test will read fairly high. Most people can't distinguish the difference between OTO readings from 2.5 to well above 5.

You need to shock because of the CC reading. CC is removed by the combination of sunlight and high FC levels.

The OTO test is very good at telling you if you have any chlorine or none. All of the other tests can sometimes read zero when the FC level is very high (especially the DPD test, which is very prone to this problem). When someone says yes/no test, yes means chlorine and no means no chlorine. The OTO test is much less useful at telling you how much chlorine you have, because it is so difficult to tell the shades of yellow apart.