volume peoples, pure volume. Turn it off & see what falls,
thats cheating. you know what your pipework diameter is & the length, so perform your 10th grade maths.
& negate the first 3 inchs from the top of your
sump to know what level your aiming for.
back siphon without getting scientific & without a check system will always be the lowest entry point, however with Donuts modular tubing, i wouldn't have thought it would penetrate the water to great depth, hence a few gal absolute max.
