PDA

View Full Version : PH tester hard to read



mshumack
04-03-2006, 02:54 PM
I have Ben's test kit with the combination PH and Chlorine tester. I have a hard time telling the difference between the shades of red. I can't tell for sure whetehr I have 7.2 or 7.8. Perhaps I'm partially color blind - maybe I'm just old.
Is there another tester available that would give a more definative result for PH in the 7.0 to 8.0 range? Is there a digital display type tester for PH?
Thanks.

waterbear
04-03-2006, 05:04 PM
pretty much all drop based pH test kits for pools use the same reagent (phenol red) which goes from orangish in acidic water thru red to purplish in alkaline water. Many men have difficulty in telling apart different shades of red or intensities (like with a DPD Chlorine test). I believe I read about it on the Taylor Technologies website but it could have been elsewhere on the net. Best bet is to ge a pH meter. LaMotte makes a pretty decent one for under $100. A meter is probably the best way to test pH if you want accuracy(not really needed for a pool to that extent) and is VERY easy to use but the BIG PROBLEM WITH THEM IS THAT YOU MUST KEEP THEM CALIBRATED OR THE READINGS ARE WORTHLESS (and the probes can break and do need to be replaced eventually)!
Now that I have your attention:D If you want to spend the money and keep it calibrated a meter might be the way to go for you! You might also try to teach your brain to learn to read the differences in the color of different pH readings. Pretty easy to do. fill the sample tube almost to the line with tap water(leave a little extra space than a regular pH test) and add just a pinch of borax to make the water alkaline. Add the pH reagent and then start adding vinegar drop by drop and watch the color change until you get to the lowest pH reading in the test block. If the tube fills up just pour a bit off and continue to add the vinegar. Try doing this a few times. Once you become familier with the different colors it really does become easier to tell them apart!

duraleigh
04-03-2006, 05:09 PM
My two kids and I did "consensus" readings when we first started. In just a few days (tests) we were able to get almost identical opinions even if we tested seperately. It get easier if you keep practicing.

Dave S.