My readings vs. Pool store

[Guest]

This web site is great! (Sorry, just had to get that off my chest.)

My readings recently have been pretty good this summer (TA a tad low, I guess). This is from this morning:

FC= 5.5
CC= 0.0
pH= 7.4
TA= 70
CH= 70
CYA= 50 (last summer my CYA was a bit lower, but everything else about the same)

I use Chlorox, Borax, and baking soda, supplemented frequently with some 3" tablets I have leftover from last year. And it's been fine until recently, when it's gotten a tad cloudy with a hint of green (probably needs a shock). So, I brought a sample to my local pool store to see what they say. I was surprised that their readings were so different. Here's a few samples:

FC= 3.4
TC= 4.2
pH= 6.9
TA= 86
Adj TA= 74
Tot Hardness= 120 (what's this??)
CYA= 40

They recommended 19.5 lbs of "Balance Pak 100" to increase TA, and 1.75 lbs of "Balance Pak 200" to increase pH - or, they said I could just shock it instead (which I'll probably do tonight).

What concerns me most is how different my readings are from their readings. Especially the pH. All summer, I've been getting 7.4 - and just last night I used both the Taylor test kit I have and an cheap HTH kit, and they both said 7.4. But the pool store says it's 6.9!

I've frequently read on this website and others that you can't trust the readings from the pool store, but should I? I'm having self doubts about my testing!

Any words of wisdom and advice is welcome.

-Dan-
P.S. In case you haven't heard, the last 2 weeks here in St. Louis have been brutal - close to 110 degrees every day, with no clouds or rain. Finally got a little rain last night though, and they're predicting that this heat wave may break soon.

 

[duraleigh]

I've frequently read on this website and others that you can't trust the readings from the pool store, but should I? I'm having self doubts about my testing!

The title of your post was all I read, but it was enough...

ALWAYS trust your tests over a pool store test unless you insist on using test strips....then don't trust either one. :lol:

The TF-100 and the Taylor K-2006 are the test kits of choice because they test exactly what needs to be tested and they are dependable and accurate.

Disregard every test you get from a pool store when you have your own, high quality kit.

 

[JasonLion]

+1 for what duraleigh said. You would be amazed at how wildly wrong pool stores frequently are. If you can get the same result twice in a row you are doing way better than they are.

Total hardness (TH) is the sum of calcium hardness (CH) and magnesium hardness (MH). Magnesium really doesn't matter much at all, while knowing CH is sometimes important, so TH is essentially useless. You can also ignore Adj TA, which is only used for one obscure calculation that you essentially never need to do.

 

[AaronGo]

I took a sample to the local pool store on Sat and already got a dose of how wrong their results can be. I immediately bought a TF-100 test kit the same day. While I am only using test strips until my TF-100 comes in, my FC results were WILDLY different from the pool store's results. Once was enough for me to know I should be doing my own testing.

 

[Samantha Sabrina]

Hi Dan,

Sorry I can't help with the test readings, no experience yet, so I leave that to the experts here.

I just wanted to say Hey Neighbor, good to see someone else close by hanging out here.

Cheers