Kathy,
Welcome to reefs.org!
here's how I responded to a very similar question:
"OT, I'm afraid you've been given some misleading info regarding trace element levels by your LFS. My current method of replenishing trace elements is to do water changes--nothing more. There is absolutely no need to dose with trace elements if you're doing regular water changes; for me this is around once a week, maybe 5% of the water. It is very, very difficult to test for some of the elements, as well as time consuming. Also, some of these elements can actually be harmful if overdosed. I find it infinitely easier to mix up a small amount of water (even easier on a nano) and just change it, knowing that all the elements are in the correct proportions in the new water. If you want to spend time and money with additives and test kits, your LFS will love you for it
The one exception to this rule is Ca/Alk, especially in a tank containing stony corals. Calcium and alkalinity can be maintained a number of different ways: Kalk, 2 part additives, etc. All have their merits and you should look into them a bit before deciding to purchase. Personally, I prefer Kalk. Brandon uses a 2 part additive. Both will work fine.
It is worth it to buy high quality test kits for the necessities though. I use a digital pH monitor,
refractometer for salinity, a digital thermometer from Radio Shack (calibrated to a lab grade therm.) and Salifert brand test kits for Ca and Alk. Most hydrometers are terribly inaccurate. If you can find someone with a refractometer that you can compare it to, it can't hurt."
I hope this helps,
Matt
