Devices for measuring parameters?

[jipps]

I have never really been so great with matching the colors of liquids to the colors on the card. It's always been a real pain for me because honestly I always have to pick between about three different possible choices and I'm never really sure for most of my tests. Are there any recommended devices for checking parameters?

I know there are devices for pH and TDS - which are recommended here?

Are there devices for other tests?

[tims]

check any of the sponors, look at the pin points.. you can get a hand held ph meter or a probe. the TDS is great for measureing your RO water values.
a lot if not most of the other test are colormatrix