your better off trying to culture pods IMO.
as for making food for a saltwater tank, thats easy. a local fish market is FULL of things to use. you can also check asian markets as they have algae sheets and other seafood. using actual fish foods too works as well and i suggest including some into the mix.
PRE - RINSE EVERYTHING that can be pre-rinsed prior to mixing and blending. ( and blend when the wife isnt home as she'll freak about her food processor ) this includes pre-rinsing frozen fish food cubes which before being fed should be getting pre-rinsed anyways as they are full of nitrates and phosphates. its easy to do this, just use a fishing net and poor RO water over it, or put the net into a small pan of RO water until you see how nasty the water color turns, swish it around alittle, dump out that water and repeat. you will be SHOCKED how dirty those frozen cubes are BTW.
after pre-rinsing what you can ( you cant to planktons and finer foods obv ) you want to chop your fish, clams, shrimp, whatever it is you have into a mush with the food processor. i usually do this on a bulk scale and will add lots of other things like a can of saltwater flakes ( which i really think is like flavored cardboard ) which helps better hold the food mush together, a bottle of garlic and a bottle of selcon, a few of the reef nutrition bottles if i have them on hand too. a few algae sheets grinded up is good too.
after you have your mix put a piece of wax paper on a cookie sheet, lay a sheet of eggcrate ontop of that, spread the mush into each of the squares of eggcrate and freeze. once frozen remove and pop the food squares out of the eggcrate. collect your squares and put them into a ziplock bag and back into the freezer.
the most important step is to immediately wash out the food processor before the wife returns home.
its that simple.