In article , says...

I've been wondering what test kits (brand) I should buy.

I've found an API master test kit for $15.00 (includes pH, high-range
pH, nitrite, nitrate, and ammonia). Since basically any two kits
allone would cost this much, I think its a good buy. But I was
wondering if people have suggestions other than the API kits. I've
tried dip strips but have real trouble reading them since they never
seem to stop changing color.

I would also like a KH and GH test (I have very hard water). I was
told that I shouldn't care about GH only KH and that the GH tests are
worthless since the testube can never be cleaned well enough to get a
good second reading. I was wondering what peoples comments are on
this.


I've tried quite a few of them. Many are not worth the powder it would take to
blow them up. One of the general purpose ones that I find decent is the Tetra
Laborett. It comes in at $13-15 mail order and includes tests for pH, ammonia,
nitrite, GH and KH. It also includes a handy syringe for taking water samples.

For nitrate, I think the standalone Tetra is the one I find easiest to get a good
reading. But it has 4 reagents, one being zinc powder. The Hagen and some other
kits have finely divided zinc in solution in a bottle which can be problematic.
Also, Hagen's kit is an example of the kind that I find very hard to read. There
is no color change, only the saturation of the color changes. This makes it hard
to get a good reading, especially when comparing the liquid in a test tube to
printed paper.

All the GH and KH test kits that I have seen are easy to use and work well. Unless
you have some really unusual water conditions it is easy to repeat the test and
get the same result. These are all titration tests, so there is no color
interpretation. Just count the number of drops until the color changes
dramatically.