Difference between test strips and taylor kit

[mader]

I have 2 types of test strips, and i just purchased a taylor kit.  Upon refilling my spa, I tested with the taylor kit (phenol red) and it reads 8.  But then I tested with the strips, and they BOTH read 7.5.

I'm not sure if my taylor kit has an issue?  What could cause this?

I have done several tests over multiple days.  My bromine (floater) is at 3-4PPM.  I also tried my tap water, which yielded the same PH.  And, i also added the thiosulfate drops prior to the phenol red to neutralize the chlorine.

Any advice?   Thanks!

[Brookenstein]

I used multiple test strips for the past year.  My results with the test strips were always perfect, each type gave the same results.  I bought a Taylor test kit about 2 weeks ago.  My results have been off the chart each time with the Taylor kit.  The understanding here (on the board) is that Taylor test kits are more accurate if performed correctly.  Some people though say that they still use the test strips and its not worth stressing about....

I'm working on lowering my levels and will test about once a week, but I'm not going to micromanage my water now.

[Chad]

I'm not sure if my taylor kit has an issue?  What could cause this?

It's not the Taylor, it's the strips that were giving you a false sense of gratitude. If your using it correctly, the Taylor results are hands down more accurate then those friggin' strips. I used strips for about a week then switched to the k-2005 and have been using it for about 11 weeks now and I feel so much better knowing what all my levels are exactly with no guessing. The only consistent results between the strips and Taylor was FC and even then....... :-/ All other readings were way off. CH was nearly 150ppm different!!!
What kit did you buy?

And, i also added the thiosulfate drops prior to the phenol red to neutralize the chlorine.

I have a k-2005 and it only states to add the thiosulfate drops when testing for Alk. The ph test is just adding 5 drops of the phenal red to the sample.

 My bromine (floater) is at 3-4PPM.  

I'm not familiar with bromine as I use dichlor as my primary sanitizer but maybe the 3-4 ppm is skewing your results a little. I'm not sure if it helps or not but I only test my ph/alk when FC is 1 or less.

[Steve]

Strips have always been useful as a "guideline" and are nowhere as accurate as the phenol red and dpd drops.

As long as your bromine is under 5ppm (max range) it shouldn't bleach the results.

Strips also have an expiry date on them so maybe check that.

Steve

[mader]

Thanks all.  I have the K-2005 complete (high).  I'm sure it is much more accurate than the strips.  Thats why i bought it., but man, how can the PH be 8 on the taylor and low 7s on the strips (2 unique strip makers too).

Guess the only way is to bring it to a dealer to test.

[Chad]

how can the PH be 8 on the taylor and low 7s on the strips (2 unique strip makers too).

I think Steve put it best. re: Strips have always been useful as a "guideline"

[tony]

Thanks all.  I have the K-2005 complete (high).  I'm sure it is much more accurate than the strips.  Thats why i bought it., but man, how can the PH be 8 on the taylor and low 7s on the strips (2 unique strip makers too).

Guess the only way is to bring it to a dealer to test.

I wouldn't necessarily trust the dealers results either.  Its all in how you see the colors.  FWIW, my readings were that far off between the strips and the Taylor kit.  Your best bet, IMO, is to become good at being your own chemist and trust the Taylor tests.

[macejh]

We've been using strips (brilliance brand) for about 6 weeks or so. I've been pretty un-happy with the strips, sometimes i cant see the difference between the colors on the code and therefore, cant get a good indication of where my numbers are.

We just bought a test Kit and should be shipped soon. I'm looking forward to seeing the real numbers of my water.  How often should I have to refill the regents in the K-2005?  We use a Brilliance 100% bromine system (no clorine aditive).  

[Chad]

 How often should I have to refill the regents in the K-2005?  

It's suggested to replace the solutions once each year.

I've had my k-2005 for about 11 weeks and the ones that I used the most so far are R-0009, R-0001, and R-0002. All are more than halfway gone already (I got a little carried away when I first got it.)
I also use my R-0003 alot. (It's about 2/5 gone)

So I would guess that those solutions should last atleast 6 months(with normal use ) and the others will last a whole year. :-/

[mader]

I posted the original post here and wanted to follow up.  There is definitely an issue with the taylor test kit, or something in the water interfering with the PH test.

I took a sample of tap water and tested it.  The test strips (2 brands) both came up with ph sub 7 (6.7 or so).  The taylor kit gives me a purple/red result that is closest to 8.0.  The tests for alk, calcium, and chlorine/bromine all matched between the strips and the taylor kit (40, 100, <1, respectively).

So what is happening?  I've tried adding the thiosulfate in 1, 2, and 5 drops.  The tap water test removes that from the equation anyway.

Perplexed.

[Chad]

I posted the original post here and wanted to follow up.  There is definitely an issue with the taylor test kit, or something in the water interfering with the PH test.

I took a sample of tap water and tested it.  The test strips (2 brands) both came up with ph sub 7 (6.7 or so).  The taylor kit gives me a purple/red result that is closest to 8.0.  The tests for alk, calcium, and chlorine/bromine all matched between the strips and the taylor kit (40, 100, <1, respectively).

So what is happening?  I've tried adding the thiosulfate in 1, 2, and 5 drops.  The tap water test removes that from the equation anyway.

Perplexed.

My taylor doesn't say to put any thiosulfate drops in for the ph test. It just states to add 5 drops of phenal red to the sample. Have you tested the ph this way yet? Are you filling the ph cell to the proper mark? How old are your solutions?

[mader]

i've tested with and without adding the thiosulfate.  If you read the manual that comes with the kit (in the FAQ section), it states that chlorine/bromine can interfer if they are at high levels.

Yes, I am definitely filling the compartment to the right level.  44ml i believe.  The kit is brand new, though I suppose the phenol red could be "old", but I have no way to determine that.

[Reese]

I've also had problems correlating pH results between test strips and Taylor -- with Taylor usually reading higher, but not to the extreme you are experiencing.  Given the diffuculty I had determining color gradiations on the strips, I just trust the Taylor reading.  FYI, some water sources give false readings fresh out of the tap.  My water tests perfect out of the tap, but true readings of high pH/TA show up the next day.  Given your situation, I'd take samples of fresh tap water, day old tap, and the tub to a dealer or two to do a correlation, or get some controls of known pH value to calibrate your results.  You may also want to contact Taylor to see if they have any suggestions.  Have the lot number of your reagent handy.  I believe it is on the bottom of the label.  

Thiosulfate has a high pH, so even one drop could skew your results, if there isn't enough sanitizer present to offset it.  It is best to test balance components when sanitizer levels are low, but that is hard to do with a bromine floater.  Besides age, temp extremes can affect reagents/chems.  I just got a shipment from an on-line vendor via UPS that froze in transit.  If it had included reagent, I'd be concerned -- but there was nothing sensitive in it.

[bluesman]

Where's the best place to get a Taylor test kit? How much would I expect to pay?

Thanks,

Bluesman 8-)

[Chad]

Where's the best place to get a Taylor test kit? How much would I expect to pay?

Thanks,

Bluesman 8-)

I don't like ordering online and I was in quite a hurry(as my test strips were "killing"me), so I got mine from my local Leslie's Pool Supply for around $40. Turns out, that's a very good price.