I know there has to be a way to make this thing work. It does in one of 5 toilets in my house but not for the other four. I am going to figure out how to modify it to work, but my physics training is out of date and I might not live long enough to figure it out. The SP7 is great. I am not giving up and will post my fix when I figure it out. My toilets are all low flow as is now recommended for all residential applications.
I have one of those 1 gal. tanks and found plenty of room to fit the dispenser in it. It saves me a lot of money over the alternative cleaners such as the tank tablets. I filled it up with toilet bowl cleaner, put it in the tank, and now the toilet cleans itself.
The dispenser doesn't work in low flow toilets... I didn't think about that when I bought one for EACH toilet in our house. So if you have this type of toilet, stay away from this dispenser. It's a great idea, just not a "universal" product.