I have very high water pressure in my city water system, and my little float valve has no problem holding that.... so anyone with a second res higher up will have no problem using it to flow into the main res. I know, because I've been doing it whenever I have to leave for out of town. After several months, you may want to clean it but that's about it.
My float is adjustable, but only up to the size of the arm, but of course the longer the arm of the float is the more adjustable it is. My float can adjust about 3 or 4" max. There are some floats with an arm 10 or 12" long which would give you more to adjust, but the negative aspect of that is the arm gets in the way of other things, such as hoses and water pumps inside the res.

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SpaceNeedle Reviewed by SpaceNeedle on . Idea: Is it mine? Auto fill reservior using tiolet tank float? Has anyone ever thought of using a toilet tank float to auto fill your DWC reservoir? I've searched the threads and haven't found anything. Rating: 5