[I've read it done both ways. Peter might have some good insight, as well as Mrs Kevin.
Personally, I don't think clams want to be handled ever other day. And you do have to feed them at least every other day. They have a foot that they extend to attach themselves and you wouldn't want to damage that food as you pulled the clam out just to feed it, right?
Figure out your total water volume, then match that number with the correct dosage of DTs. Then <u>gradually</u> over time, you can increase that amount of food up to double that amount. The benefit is you won't be feeding only the clam, but all types of micro fauna, including copepods, ampipods, feather dusters, sponges and more. I don't know it for a fact, but I think corals snack on it as well.
Another good thing I've noticed by feeding DTs is that I have less algae growing on the glass. Less cleanings necessary.]