Minimum Clearances when drilling an overflow

[sphelps]

Originally Posted by ensquire

my question is this.
When we throttle pumps down with a valve , does this not make them noisier ??
I will start a build thread to carry these ideas on with.

I depends on the pump and the quiet ones do sometimes make more noise with more head pressure but not always. In general a pump shouldn't be any nosier but different people have different results. When you close a ball valve it just increases the head pressure which is the same as lifting your tank higher above the sump. In addition you pump should use less power with more head pressure.

With the tank already assembled and already drilled I personally wouldn't try and drill a larger hole on top of a smaller hole unless it was absolutely necessary, and I've drilled a lot of tanks before.