The only think I've ever used Grapefruit seed extract for is to clean cages. I use 50 drops to a VERY Lg squirt bottle of water. Spray it on, wait and wipe it off. It is wonderful, in fact I've even cleaned my oven with it! It doesn't clean like "Easy Off" (but the fumes also won't make you fall on the floor in a dead faint!

) But it is pretty amazing if you spray a generous amt on, walk away for 30 mins and come back.
I use ACV (apple cider vinegar) three tablespoons to about 1/2 gallon of water. I use this about 1 every month and a half or so. I use this in their water bowls exclusively for one week.
Aloe Detox is amazing. In general, I've had wonderful success with it. I add 1 cap full to water for LARGE macaws, 1/2 cap for medium sized and about 1/4 for the tiels. I use it for about 1 week. If I think it is having too much of a laxative affect, I cut down to one bowl of fresh plain water and one bowl w/aloe detox per day.
To be honest I've never given GSE internally---I need to read more about it in order to understand it better.