Alan is one of the folks that did a number for the Discus tanks of some of the local members here.

It uses a timer and slowly drains and fills.
The set up uses a small polypropylene semi rigid tubing for the drain and fill.
This allows a slow water change from a sump.

A float switch fills the water and the timer drains it.

A simple Python styled water changer DIY or you can buy from them is a simple way to remove any bucket work.

I use hard plumbed PVC for most of the fill and drain things.
I turn a knob, I drain, I turn another, I fill.

My client tanks are all set up this way. Takes me 40 minutes to drain and fill 200+ galllons of water with out ever touch a bucket or a hose.

I'll post more on this later.

Regards,
Tom Barr