Not all organic food is sutable to keep in a reservoir.I would of thought Canna would be OK but I'd check if you haven't.If money isnt an issue I'd use Advanced Nutrients Iguana Juice.I can't see why UV would hurt your nutes as they don't have anything living in them do they?No microbes,bacteria?Canna have a good site,check but I can't recommend Iguana juice enough,the ingrediants far supirior to anything else out there.Made for growers like us.Developed on our plants.Their site is full of info.