Seeking advice for water testing with ColorQ Pro and ePool

[Surfix007]

Dear forum members,
I love to have a clean pool and enjoy taking care of it (and use it!). I also learned over the years that it is a lot easier to always stay on top of it and keep it balanced. I have an inground pool, roughly 24,000 gal, blaster, variable speed pool pump and sand filter. Last year I added a flow meter in the return to make proper use of the variable speed pump and I also got an ePool which I think is a great tool to have. Because I am traveling a lot, my wife can easily take care of the basics and I will do the rest if needed when i am back.
This year (couple days ago) I bought the ColorQ pro 7 water test kit but it looks like I am not doing it right or it just doesn't work. So far I tested the water twice and at the same time took a sample to my local pool store (as I have done for the past years). The results are so different. Here are some samples:
Abrev | Pool Store | ColorQ Pro7
FAC | 5 | Hi
TAC | 5 | Hi
CH | 280 | 458
TA | 110 | 130
PH | 7.8 | 7.6
The difference of the previous results are even more off (CH | 220 | 597).
Does anybody have any idea what the reason for these different results could be?
Thank you so much for helping,
Regards
Surfix007

[Surfix007]

Update 1:
I sent the information to LaMotte and within 24h I got a reply. They wanted to know the serial number of the ColorQ as well as the batch numbers for the agents. Let's see what they come up with. I will keep you posted.
Thanks
Surfix007
ps: Is it true that I am the only one having problems with ColorQ Pro7???

[Watermom]

Good that they got back to you so quickly. I don't know if it's true or not that others don't have trouble with the ColorQ Pr7 but will say that there aren't many people on the forum who use that tester. Most people here use the Taylor K-2006.

[PoolDoc]

Is it true that I am the only one having problems with ColorQ Pro7???

Nah. But most people having problems with it, don't know.

The ColorQ is a mini-colorimeter and is potentially accurate, within its limitations. But there are a lot of limitations inherent in low-cost low-capability spectrophotometer. Here's a *real* spectrophotometer from LaMotte: LaMotte 2000-01 SMART Spectro Spectrophotometer (http://www.amazon.com/LaMotte-2000-01-SMART-Spectro-Spectrophotometer/dp/B00BT17EFI)

LaMotte would never admit it, but you have the 'Lego' version of a spectrophotometer. But you wouldn't even want the real one! While they are potentially very, very accurate, they require special sample prep and don't measure the ranges you need. So you'd have to do hyper accurate dilutions to actually test your pool.

In a sense, the Taylor K2006 is the 'Lego' version of a titration lab, like this kit (http://www.amazon.com/Master-Vintner-Acid-Titration-Kit/dp/B0064OQ2E4/) used by brewers. But it's much easier to scale down a titration lab, than a spectrophotometer. And titration measurements (drop counts, in this case) intrinsically have the wide range you need to test pool water.

Ok. I hate to say it, but you've really been 'pool-stored' to use CarlD's neologism: not only is the ColorQ Pro not very good, but the ePool is worthless. The temperature gauge works. The rest of it -- unless you routinely calibrate the pH electrode, the pH measurements are unreliable. And the chlorine read-out is worse: it's INFERRED (ie, guessed-at electronically) from an ORP measurement, which is something else I'm not going to explain here, but is NOT chlorine.

Just get a K2006. And a K1000 for quick testing. http://pool9.net/testkits/

Since you travel a lot, you may want to get a phosphate testkit:

Hach (AquaChek) 562227 Phosphate Test Kit (http://www.amazon.com/exec/obidos/ASIN/B004L4RPW2/scouscho-20)
Taylor Technologies Inc K-1106 Test Kit Phosphate (http://www.amazon.com/exec/obidos/ASIN/B003V4QUDI/scouscho-20/)

We don't usually recommend messing with lowered phosphates, but maintaining very low phosphates WILL make your pool less likely to grow a nice swamp crop of algae if the pool is neglected for a few days. Low phosphates + polyquat will enable you to leave for a week and return to a problem free pool -- usually. http://pool9.net/polyquat/
Ask me how, once you know more: it's not just a matter of dump it in and forget it. It needs to be a part of a plan.

By the way, Lamotte does have a version of the K2006, complete with FAS-DPD titration (drop counting) for chlorine. It's probably OK, but I haven't heard of anyone using one, since it costs 3x as much as the K2006.

[Surfix007]

Ok, I thought I will provide some results from talking to LaMotte. As mentioned before, they responded quite quickly and after a few emails they sent me a sample of water with the exact measurements written on the bottle. I performed the tests and - YES, I read the tips & tricks, ensured that the tubes were dry from the outside, and and and . However, my results where still off - quite a bit.
I sent in the results I got and the answer was that the water was in transit for some time and according to this the deviations are "normal." I am still not happy with the ColorQ Pro7 and when comparing my measurements with the values written on the bottle, I am out of range with Alkalinity, Hardness is off, and PH is lower. In summary, I must say that the test-kit is useless for me. I will probably get the K-2006 and sell the ColorQ Pro7 (anybody interested? Only used for less then 10 tests ;-).
Hope this will be helpful for people that are also looking for a "test kit."
Thanks
Surfix007

[PoolDoc]

Yes, I'd be interested in the ColorQ, since I'd rather not buy one for full price, but I'd like to get my hands on one, since they are being sold more and more widely. Email me at poolforum@gmail.com. Perhaps I can swap you a new K2006C for your ColorQ.

I've done a bit more checking, and the ColorQ is not too bad, in some respects. Apparently, it's faster than using the K2006, and the FC /CC are accurate within the limited range (0 - 5 ppm). PH is reportedly as accurate as the K2006 and the TA is nearly as accurate. The calcium test is apparently finicky and problematic. Readings over 300(?) are suspect. CYA results are erratic.

Regarding Lamotte's "the sample change" -- that's possible. But they should have warned you of that up front. Calcium and CYA levels should not have been affected. Alkalinity levels should have been stable if the sample wasn't overheated, AND if they left no air space in the bottle. PH would have changed if the alkalinity did, but might not have been stable in any case. Trying to come up with a chlorine sample that would be stable in transit -- without refrigeration -- is hard.

[waterbear]

PoolDoc is exactly on the money concerning the ColorQ and the LaMotte Waterlink Express professional water testing stations have similar limitations (I used to use the system). When you convert a titration test to a colormetric test you limit its range and sensitivity, even with a meter to read the sample. I had converstions with LaMotte tech support when the system first came out and was told that for a $100 meter it's not bad but is is a $100 meter!