that is largely due to oxygen available to bacs and bacs in general, if you keep the mix in clean containers and keep them closed it is less likely to happen so fast but marple is fancy stuff for a grow, rather have this on my pan cakesi've tried the sweet leaf and turbinado sugar. they both start to form a film in the water after a couple days. i fill and mix a 2 gallon jug and use it for a bout 5 - 6 days. by day 3 it's getting cloudy. the black strap molasses is the only thing that hasn't gummed up "yet". i am in SOIL. i have never tried syrup. probably to processed.