Is Flake Food Necessary if feeding Frozen?

[Commodore 64]

I have a 55g tank with about 20 assorted shrimp (amano, cherry, bamboo, bumblebee, emerald), 5 mollies, 2 clown loaches, and 1 CAE. For the past few months, I've been feeding them primarily frozen cube, from some variety-type pack purchased from the LFS.
(http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+7927+8130&pcatid=8130) I feed 1 cube in the morning and 1 cube at night, and sometimes add a few Omega One Algae Discs. Now my fish won't even touch the Omega One flakes.

So I have a few questions:

1. Am I feeding too little/too much? It all gets devoured in less than 2 minutes (except for the discs), and I worry that there won't be enough suspended detritus to sustain my bamboo shrimp.

2. Do I need to worry about flakes or pellets? Or can I just keep on feeding frozen?

I vacuum the gravel about once every 2 weeks and I do note a fair amount of particulate matter when I do. Ammonia/nitrite levels are 0 though. The tank has a couple elodea strands in it, but other than that it's all rocks (I stick mostly to inert rocks like quartz-sandstones, orthoquartzites, and quartzites), plastic plants, and gravel.

[smaug]

I feed a variety of frozen foods but I do not think that it would be an ideal diet to Frozen is best fed 3-4 times a week as an extra.I would try and wean them off of getting it everyday and go back to your main staple being a good quality flake or granule.As for you flower shrimp,there should be that much floating detritus in you water from feeding,that would mean you are over feeding.I am unsure as to how to keep a flower shrimp properly fed but have an abundance of leftover food would not be the answer.