test strips

[waterbear]

i was wondering about the correct way to use a test strip, the direction tell you to take a quick reading,how much time to you really have, i notice they get darker very quick,not even enough time to write them all down .so whats the correct method,and would anyone know of a electonic tester thats reasonable,that seems to me the more accurate way to go thanks for any info

IMHO, electronic testers are not worth the trouble. I have used them in salt water aquariums (and in laboratory settings) but NEVER used them for my pool!!
Electronic testers fall into two groups. Direct reading meters for such things as pH, ORP, TDS, and Salinity and they require calibration for accurate results. The calibaration has to be perfomed constantly and is more involved than using a drop based kit! There are also other drawbacks (not including price) such as electrodes being fragile and subject to breakage or needing to be stored wet. IMHO, you will spend MORE time with 'wet end' work with one of these than with a drop based kit.

The second group are colorimeters and turbidity meters. Once again, calibration against standards is crucial if you want to depend on the results.
These read the color or cloudiness electronically instead of us using our eyes to compare the results with a color block. You still have to do the test with reagents!
For tests that change color such as chlorine levels or pH they can, in theory, provide much more accurate results but the question becomes whether that amount of accuracy is necessary for our purposes. Given the price involved the drop based kits are the clear winners again! If you do decide to go the route of a colorimeter you want one that uses liquid (or dry) reagent tests and not one that reads test strips!

There is a difference between precision and accuracy. Electronic meters can give you a more precise reading but it does not mean that it is a more accurate reading. Ben (PoolDoc) can explain this much better than I can without getting overly technical but the bottom line is that a drop based kit is going to be more accurate than a test strip. An electronic meter will give you a more precise reading on the test but if the accuracy of that particular test is +/_ 10 ppm what good does it do you to have a meter tell you your reading is 157 ppm vs 160 ppm? Your actual reading might be 147 ppm or 167 ppm!
Hope this info is helpful to you!

[Lenny]

As soon as you buy a drop based kit, you'll realize how lousy test strips are. I had some test strips (2 different brands) and thought they might be useful for quick readings or to confirm my drops based results.

I found that they're not even good enough for that so I threw them away.

[DavidD]

Yeah, I had a friend that swore his CYA was below 60 because of test strips. Turns out it was above 150. Now they were cheap Wal Mart strips but still, that's a BIG difference.

[PoolDoc]

Now they were cheap Wal Mart strips but still, that's a BIG difference.

Uh-h, WalMart's test strips are mostly made by one of the major strip manufacturers. They may be cheaper, but they aren't likely to be any worse!

PoolDoc.