Water testing variances

[rjward]

Hello all. Many thanks for all of the shared information on this site. Please pardon any posting mistakes that I may make - hopefully my sig shows the needed info on my pool. Water is crystal clear and I'm using a stenner pump for bleach injection.
My main goal is to get up to speed on my testing process before warmer weather arrives. The pool is three months old and pH / Alkalinity are holding fairly steady.

I have the TF100 kit as well as the Rainbow kit that came with the pool. I have pebblesheen and for warranty purposes I am required to use a store with computerized records. In order to assess the validity of the store results, I did my own tests and then took a sample to three different stores. No surprise - there is a fairly wide range of variance in the results and I would greatly value your collective feedback on the results and specifically your advice on Alkalinity as that is where even my tests vary.

The three stores I will refer to as stores W,T, and L. My results are all from TF100 as well as the rainbow for Alkalinity. Hopefully my attemp at a 'chart' will work. Many thanks in advance for any feedback / observations / reccomendations!!

------W--------T--------L--------TF100 / Rainbow
FC----4--------1.8-------2--------2
TC----4--------1.8-------2--------2
pH----7.6------7.2-------7.6------7.5
TA----55-------78-------100------60 / 90
CH----220------258------210------310
CYA---80-------27-------25-------25

 

[JasonLion]

Store testing simply isn't very reliable. W is clearly wrong on CYA, and FC. T is clearly wrong on PH. L is high on TA and their CH results seems rather unlikely. None of this is at all surprising, store testing is way off amazingly often.

I'd go with the TF100 test results over everything else. Of these results, clearly FC/TC is around 2, PH is around 7.6, TA is around 60 or 70, CYA is around 30. The only one that isn't obvious is CH, which is somewhere between 200 and 320, most likely around 300 but hard to be sure.

 

[rjward]

Thanks for the confirmation. I'm sticking with the TF100 results and will get make the monthly rounds for warranty purposes. Maybe I'm a little disturbed, but I must say I rather enjoy visiting the stores and seeing their results and watching their attempts to hawk products. Fortunately I've been lurking on here for several months soaking in the info and have not been PoolStored!
"OMG YOUR PHOSPHATES ARE THROUGH THE ROOF - IS YOUR POOL A SWAMP? YOU NEED THIS!"

Thanks again

 

[UnderWaterVanya]

"OMG YOUR PHOSPHATES ARE THROUGH THE ROOF - IS YOUR POOL A SWAMP? YOU NEED THIS!"

What do you say when they say this?

 

[rjward]

It really depends on the mood I'm in and the attitude of the clerk. Sometimes I like to play with them just to hear what they have to say, other times I just shake my head and walk away. Then there's the classic snort of derision.....