From what I read, you need to be intensely clean. Pool cleaning products can be used to clean trays. I have read of people getting mold in the fodder and killing their cows from it, so it's nothing to take lightly. If it's barley that you are sprouting, sometimes the barley husk itself can be the source of the contamination. It needs to be soaked or washed before using. I would use a diluted peroxide and water mixture. You can also use peroxide in your reservoir instead of chlorine if you want.

We are in the same position as you and wondered how you got on? What did you end up doing?