This is just a random note on dried foods in general; flakes and pellets.
I buy Ken's and others in bulk too, but even with about 900 gallons of water, it can still take me a bit of time to go through a 1/2 pound bag.
Two things will break them down and quickly: Light and air exposure.
I wish I still had the link, but it was like a good old slap upside the head. It really made me wake up and take note of how I was handling and storing my flake foods. After a gazillion years in the hobby, I'm now pretty religious about not leaving flakes out after feeding all the tanks. The balance goes in an air-tight jar in a cabinet in a cool part of the house. I'm stopping short of refrigerating it as I've pushed my luck for years with the quantity of frozen food I keep in the freezer. I really don't want to see where my wife's patience bottom's out.
Some flakes come in canisters that prevent light exposure and some don't. So that bulk foods like Ken's, need to be re-packed to prevent light exposure, as well as air exposure. Mason jars stored in a cabinet work well, though any airtight canister would too. I empty the 1/2 lb bags into mason jars and work my way through them, storing them in a cabinet.