strange pH results

[waterbear]

I would test both your pH reagents with the acid and base demand reagents in the K-2006 to see how quickly the color changes.. It is not unusual for phenol red to go bad. How old are the reagents? I have had them go bad after one or two seasons and when they do they read around 7.8 or 8.0 no matter what the pH is. Also, is there any contamination in the comparator of the k-2006? You might want to clean it well, rinse it with pool water and then retest.

I would test again and take a sample to the pool store and see what they come up with.I suspect it will confirm one test or the other. For the one that is "off" get new reagent and clean the comparator well.

I suspect that your R-0014 in the K-1000 kit is newer than the R-0004 in the K-2006 and is the one to be trusted.

Also, since the K-2006 uses the same comparator for the CH and pH (and TA) tests and the CH test is done at a high pH cross contamination could also be the cause.

[jhm]

I suspect that your R-0014 in the K-1000 kit is newer than the R-0004 in the K-2006 and is the one to be trusted.

Actually, it is just the opposite. I got the R-0014 with one of Doc's kits a few years ago. I got a new k-2006 this year. The old one kept rising and falling through the shock period, the new one shot through the roof.

Once the shock period was over, the R-0004 has gone back to normal and is now reading similar to the R-0014. I certainly don't understand it, but those are the results I witnessed.

Your theory of cross-contamination could explain it though. Before I shocked, I was testing both CH and TA for a couple days with both pool and source water. I probably didn't clean it like I should have, so there could have been residuals that affected it.

That or the very high FC I maintained for a few days.

Thanks for all the help from you all, I'm starting to get a handle on things finally!