here's an excellent read on clams. feeding and otherwise.
http://www.wetwebmedia.com/BookMatte...cnids-demo.pdf
Salifert semi-recently took a hit on their reputation when the owner just sort of dropped off the face of the planet after a bad batch of kits was released. calcium and alkalinity tests i believe. Prior to this incident, their kits were great and customer service was just as good, now Im not so sure. Elos kits have gained a good reputation as well.
Ive never used blackpowder, but fwiw, I never dose anything i dont test for. ever. to do so is to ask for trouble.
I hadn't realised any stores actually outright didnt like us canreefers. *shrug* I find that a little bit sad and disappointing if anything. At any rate, I agree with Levi. We aren't trying to sell you anything (excluding the classifieds...
) and the majority of us forum dwellers are good hearted people just trying to help out each other and allowing the hobby as a whole to progress further. I was in your shoes at one point (we all were) and honestly, my time spent on aquarium forums has furthered my knowledge (at least i like to think so) and saved me tons of headaches (and $). mind you, it also serves as a constant reminder of how little i actually know and have yet to discover.