Fluctuating test results

[mgzych]

Hi all,

Moved into a new house and I'm now a proud first-time (salt water chlorine generator equipped) pool owner. We had a pool shop open it for us a few weeks ago and they remarked what good shape it's in. Looks ok to me too, but I know looks can be deceiving. My wife has taken several samples of the water to a pool shop to get a comfort level that everything is in the appropriate ranges before allowing our daughter to swim, and it seems the results have been unreliable, varying from each other and from the tests I've done (only using test strips now--thinking I ought to buy a more precise test kit). Anyway, here's my question: Is there a "right" way to collect a water sample, either for pool shop or home testing that promises the most consistent and accurate results?

Thanks,
Mark

P.S. I can't wait to get my forum browsing privileges back. I thought I saw, before I registered, a thread that talked about and provided links for well-reviewed test kits. Thanks again.

[PoolDoc]

I had to grin at this one; here at the PoolForum, your question is almost a setup for the punch line!


Anyway, here's my question: Is there a "right" way to collect a water sample, either for pool shop or home testing that promises the most consistent and accurate results?

Yes, the 'right' way to collect a sample is to get water out of your pool, and take it into your kitchen . . . where YOU test it yourself, with a K-2006! That will give you much more consistent results!

Teasing aside, I've had neighbors collect ONE sample from one pool, split it amongst themselves, and then take the divided samples to their dealer, and present them as if they came from two or three pools: the results were STILL widely varying!

When you collect a sample, you really just need to watch for two things:
1. Invert the container and put it into the pool a few inches before righting it, so you collect from below the surface, instead of on the surface. (This mainly matters when there's a lot of 'goo' on the surface.)
2. Don't collect a sample from the stream of water returning to the pool via the eyeball.

The test kit page is linke in my signature -- the 'reviews' are really recommendations from me; the links are to Amazon, since you usually cannot buy these kits locally, and since I get a 4+% commission if you buy from Amazon instead of elsewhere. I think the kits are back in stock -- I know a few people paid too much for them, because EVERYTHING went out of stock at the regular sellers.over the Memorial weekend.

[mgzych]

Thanks for the quickother response.

Is Taylor the only company that makes kits with the DPD-FAS test? Does the lack of that test render all the other similar (at least superficially--I'm referring loosely to all the "add drops, compare color" tests) kits pretty much useless?

Best,
Mark

[PoolDoc]

You'd have to be specific on which test kit you have; some ARE total junk. LaMotte makes some better products but they've switched to emphasizing strips, and few people have their drops kit. They do have a FAS-DPD kit, but it costs (last time I checked) 3x what the Taylor does. FAS-DPD is the ONLY way to reliably and accurately test chlorine levels above 5 ppm. OTO (yellow drops) are reliable, but not very precise.

If you have the HTH 6-way drops test from some Walmarts, that IS a Taylor kit, but with an OTO chlorine test: it's a great deal and we often recommend it.

If you have one of the knock-off import kits . . . there's no reason one of them couldn't be high quality, but much of the Chinese merchandise I've seen is the lowest quality they can get away with, and on a test kit, you can get away with very low quality indeed, since no one (except us, and maybe TroubleFreePools.com) cross-checks test results.

TroubleFreePools is owned by a guy who is selling a clone of my PS-235 testkit (long story, but I nearly went bankrupt while making and selling an 'improved' version of the K-2006). We don't mention that kit, as a rule, for a variety of reasons, but it has no outstanding benefits over the K-2006, and because he's replaced some of the reagents with his own. They may be fine, but we don't know that, one way or the other.

Bottom line: if you don't have a Taylor, Lamotte or TFP DPD-FAS test method, as far as we know, you do NOT have a reliable way to 'measure' chlorine levels above 5 ppm. If you don't have a melamine (cloudy water) test for CYA, you really aren't measuring stabilizer at all. The other tests (pH, TA, CH) all have alternative sources, but chlorine is key, so we don't even look at the others.

[CarlD]

There is a Leslies kit available on-line, but it is merely a re-badged Taylor K-2006 in a box that says "Leslies" and a bit more expensive than the one linked here.