PDA

View Full Version : pH indicator turns blue instead of redish?



Kilolab
06-01-2007, 10:13 AM
~400 gal. spa Just cleaned and new water. Bromide OK. Alk OK. (According to strips) When I check pH the drops turn dark blue and not red.
Does anyone know why? Will check everything with drops when I get them.

CanuckPool
06-01-2007, 04:19 PM
I had the same problem when I tested my hot tub for pH. I posted awhile ago and the response I got was that it depended on the test kit I was using. The one I was using requires me to add a a drop of Chlorine Eliminator to test for Bromine... apparently these types of kits don't handle hot water too well and give weird pH readings... mine was dark purple. I also have a basic Taylor kit that I used on the hot tub and that seems to work ok.

waterbear
06-01-2007, 05:12 PM
cheap test kits that use a pH indicator without a halogen neutalizer will have this problem. If you drop your bromine levels very low then the test might work but I would recommend getting a better test kit and ditching that cheap one and your strips. For Bromine the Taylor K-2106 would be the one to go with! It will not have the problems you describe when testing your pH and will give you real numerical test results instead of "OK', "HIGH", and "LOW" like the strips do! (I know there are numbers on the strips but they are really pretty useless. Not enough precision to be of any value in water balancing!)

Also "OK" is not a valid test reading. It really doesn't tell us anything about your bromine levels (If you had posted an actual number it would have told me if your pH indicator has no halogen neutralizer built in or if your bromne levels were just on the high side, either could cause the pH results you reported). The hardness test is useless on the strips since it is testing total hardness (useless info for water balancing) and not calcium hardness (what is needed to be known for water balancing!) a GOOD test kit will pay for itself many times over and when you consider how much the tub cost it really puts into persepctive that spending about $60 on a good test kit is NOT a lot of money (and will probably soon pay for itself in chemical usage savings!)