I know it doesn't help now as you've already built the float,, but that pump intake is the culpirit causing the float to go turtle...   If you could rig up another float to attach to the  other side the pump intake it wouldn't roll over on it's back.

I know it may be necessary to clean the intake, but somesort of a float arrangement on  on the 'outboard' side of the intake would really help. Then if you needed to clean the intake you could and still have room to get to the intake to clean it.

Wouldn't take much, looks like you used 55 gal drums for the floats. Just 2 on the 'outboard side' would cure any 'submarine' problems.