Best Chlorine Test Strips?

[seabright_sc]

While I know drops are more accurate, I'd like to get my wife and teenager involved in a little water maintenance and I know strips are the place to start with them.

What strips do you recomend (most accurate) that include:

Alk

PH

Chlorine

Hardness

Anything else I'm missing?

recommendations for online retailers?

Have you compared strip results with drop kits?

Thanks

[chem geek]

So your wife and teenager are unable to take a graduated tube, take it to get a water sample, pour out until they get to the appropriate mark (say, 25 ml), and add drops while swirling as described in the instructions and then compare colors (for pH) or look for a color change (for most other tests)? I think you are underestimating their capabilities.

There are no test strips that test for Calcium Hardness (CH). Test strips can only test for Total Hardness (TH) which includes magnesium in addition to calcium and is irrelevant with regard to the saturation index since scaling occurs with calcium carbonate, not with magnesium (at levels found in natural water). So right there you are done, finished, kaput, call it a day, hang it up, etc.

Your list is missing Cyanuric Acid (CYA), though you could estimate that based on how much Dichlor you add and assuming a typical amount of breakdown each month (about 5 ppm, if the level is at around 30 ppm CYA).

The resolution and accuracy of test strips compared to the drop-based test isn't even close as you can see below:

....................................... <----------------- TEST STRIPS -----------------> ........ DROP-BASED

........................................ LaMotte Insta-Test 6 .......... Taylor sureTrack 6 ........ Taylor K-2006

Free Chlorine (FC) .......... 0, 0.25, 0.50, 1.0, 3.0, 10 ....... 0, 1, 2, 3, 5, 10 ......... every 0.2 ppm*

Combined Chlorine (CC) ..... calculate from TC-FC ............ not available ............. every 0.2 ppm*

Total Chlorine (TC) ......... 0, 0.25, 0.50, 1.0, 3.0, 10 ........ not available ............. calculate from FC+CC

pH ................................. 6.2, 6.8, 7.2, 7.8, 8.4 ... 6.4, 6.8, 7.2, 7.5, 7.8, 8.4 .. 7.0, 7.2, 7.4, 7.6, 7.8, 8.0

Total Alkalinity (TA) ........ 0, 40, 80, 120, 180, 240 .... 0, 40, 80, 120, 180, 240 ... every 10 ppm

Calcium Hardness (CH) ......... not available ................... not available ............... every 10 ppm

Total Hardness (TH) ......... 50, 100, 250, 450, 800 ..... 0, 100, 200, 400, 800 .... not available (or needed)

Cyanuric Acid (CYA) .......... 0, 40, 100, 150, 250 ....... 0, 30-50, 100, 200, 300 ... 30**-100 every 10 ppm

*The resolution is dependent on sample size where a 10 ml sample has 0.5 ppm, a 25 ml sample has 0.2 ppm.

**You can also get a CYA test that measures down to 20 ppm (so a 20-100 range every 10 ppm). The TF-100 has a much larger volume of the most commonly used reagents than the Taylor K-2006.

A doubling of Total Alkalinity (TA) from 40 to 80 ppm (at a CYA level of 30 ppm) increases the saturation index by 0.37 which is large and not insignificant. A doubling of Calcium Hardness from 50 to 100 ppm increases the saturation index by 0.3, though you can't even measure this with test strips (you can only measure Total Hardness which prevents you from calculating a real saturation index). A change in pH on the test strips of 0.4 is twice as large as that measured in the drop-based test of 0.2 and affects the saturation index by these same amounts.

The drop-based test kits are easier to see as well since the FAS-DPD chlorine test goes from pink/red to clear as you add drops as shown in the demo in this link -- something that even a color-blind person can see. The TA test transition from green to red is easy to see. The CH transition from red to blue is more difficult. The CYA turbidity test can also take a little getting used to.

Once you have your spa balanced and get into a consistent routine where the water parameters don't change much, then test strips can be useful as quick (daily) checks, but you still need to validate/verify every so often, at least 1-2 times a week (still checking daily with the test strip). This is OK because once you get your Calcium Hardness (CH) set, it won't change except from refill (for evaporation or splash-out/carry-out). The CYA will also be fairly stable once you switch from Dichlor to bleach (assuming you do that) though does slowly drop over a month's time by about 5 ppm. Once you adjust your TA to a good low level, then the pH can be fairly stable (especially if you use 50 ppm Borates -- something that IS tested with a test strip as an approximate amount is OK) though the pH should be tested most frequently (daily), as should the chlorine level.

Richard

[quantumchromodynamics]

Get a good test kit.

[seabright_sc]

Ya, ya I know test kits are better and yes the wife and daughter are capable, but the won't deal with one. So, I'm interested in the most reliable test strips.

[bart6453]

While I know drops are more accurate, I'd like to get my wife and teenager involved in a little water maintenance and I know strips are the place to start with them.

What strips do you recomend (most accurate) that include:

Alk

PH

Chlorine

Hardness

Anything else I'm missing?

recommendations for online retailers?

Have you compared strip results with drop kits?

Thanks

The best test strips I have found are the ones in the garbage.

Get a drop based test and make your life easy.

If you want to get your wife/teenager involved....make them get involved in a process that will actually work.

Nothing more frustrating that not knowing what the hell is going on and not having the ability to get clear answers from your tools.

If you use test strips, you might just as well guess.

[chem geek]

I gave a couple of examples of test strips. The Taylor ones are relatively new so I can't say how they are, but the LaMotte ones are used by people and I suppose they are as good as test strips can be (which isn't that good). I would suppose that you are not really going to have them test for things that aren't tested frequently, so really they will just be testing pH and chlorine and maybe TA, so the Insta-Test 3 should be sufficient, assuming you have a Taylor test kit you use yourself initially for getting the spa set up with proper CH, for example. So the test strips are at least a little better for the pH, chlorine and TA than for CH which they can't measure at all or for CYA where they tend to be quite poor.