We all know the strips are not as accurate, but I had to buy some to get by when I ran out of R0871 reagent. Now that my Taylor kit is full of R0871 again, I decided to do a little experiment to check the accuracy of the Aquacheck strips. I did this comparative testing over the last few days on my pool. Here are my conclusions:
FC is fairly accurate, however, as already known, it maxes at 10ppm so its no good during SLAM. Also, the issue with using the strips for FC and accuracy isnt with the strip (IMHO). Its with the bottle back, that you hold the strip up to compare. It only has a level for 0, 1, 3, 5 and 10. If it had a level that was in 1ppm increments it would be much better. I was keeping the strip in the 10ppm every day, since my goal was 9, until my R0871 came in. when I finally got my R0871, it read the same 10ppm. Trying to get a reading between 5 and 10 though, is going to be guesswork with such a broad range.
CYA - The strips are NOT even close to what the K2006 CYA test says. Strip said I had 20ppm CYA. K2006 says 50 ppm, which is where I know it is. Definately dont use these strips for CYA, as they are not even in the ball park.
TA- Believe it or not, the strips were dead on in the middle of 60 and 80 ppm. My K2006 kit hit TA right at 70ppm. I did this test for several days in a row, with the same results. I would trust the strip on TA.
pH - here is another one where I think one could get by with using the strips. It had my pH coloration smack dab in the middle of 7.2 and 7.8. My K2006 says 7.5. The issue again with the accuracy, is the broad range (7.2 - 7.8) for the comparative. If it was in increments like 7.2, 7.3, 7.4, 7.5, etc, I think this test would be very accurate. I would use the strips for daily pH testing, as you can get a good ball park reading. I would double check the strips with a drop test pH test every few days though, just to make sure.
Summary: If you have some strips laying around that you dont want to just go to waste, use them for your TA and pH as they are pretty accurate. I wouldnt bother at all with FC, or CYA as the FC is hard to judge where it is at, and the CYA test is just flat not accurate.