ha0be

My res was disgusting this morning. The bubbles from the airstone caused the brown molasses slime to look like a vomit bubble bath! Yuk! I'll be adding molasses by hand from now on!

hydroherb

That's why every says no molasses in hydroponics.

Every nasty thing you don't want growing in your reservoir looks at molasses like an all-you-can-eat smörgåsbord. If you get the slightest invasion of nasties and there's molasses in there, it goes horribly bad horribly fast. Like a big barrel of gasoline: as long as there's no spark you're fine.

It's just not possible to guarantee no bacteria will get into a reservoir.

In soil there's natural microbial life that keeps things in balance. You could probably use molasses in hydroponics if you inoculate with beneficial bacteria and the like, but at that point you've got enough money in the res that I wouldn't recommend risking an algae bloom.