Quote Originally Posted by cygnusecks
Thanks for all the great responses. Ever since deciding to build the pool I've hoped for a digital chemical reader, where I dip it in the water, and it instantly gives me a digital readout of all chem levels, and/or tells me exactly how much of what to add to bring the water into balance. I wonder what such a device would cost or if it's possible to build!

I grew up with my pool owner friends' parents always doing the "strips" or the dropper test, and always felt it very subjective. What if you're color blind, or what if your strips are bad, etc...
The HAVE devices like that...they are called digital pH meters, ORP meters, Colorimeters, turbudity meters, and conductivity meters (and possibly some others). Good ones can set you back thousands of dollars. The also require standard solutions to calibrate them and some of the electrodes needs special care such as being stored wet. They are actually more work and more time consuming in the long run and won't really give you much benifit over a drop test. You don't NEED that level of accuracy to maintain your pool!

Reagents do go bad, Strips have very little precision, but electrodes go bad and batteries get weak also and if a meter is not properly calibrated (pH meters are a horror to calibrate!) then the test results won't even be as accurate as a strip! I have worked with several of these types of electronic testers over the years in laboratory settings, as an aqaurist, and as a 'pool store guy'. I use a drop based kit for my own pool and my water is perfect.