I have a 50ltr tank out the back that all water for the birds comes from. I put a full garlic bulb into it and leave it there, after 10/14 days the water smells of garlic and it gets stronger the longer it stays in there, when it starts to rot or the shoots have grown to about a foot long out of it, i put a fresh bulb into the water tank about a week before removing the original one. I Never let the tank get less than a quarter full before topping up with fresh water again, this is used the following day for the birds Never!! on the day it has been topped up, it must lay overnight before the birds are given it. 100% Natural product that fills the Category "For all the good it does the birds, it definitely disnae do them any harm" Which was a saying my Da had about these idea's, meaning he wisnae convinced they worked but satisfied himself that even if he used this or that in the loft it widnae Harm his birds so was ok to try.