I vacuum the sand on every waterchange. Sucking out all the detritus from everywhere is very important imo otherwise the detritus will break down into phosphate and nitrate causing algae issues. When I was out of town from Jan-July I had a maintenance company do waterchanges and all he did was remove old water, add new water. Now my tank is covered in cyano, and I am having to do a lot of work to get it back in top shape. Imo, sucking the water out and adding new water isn't sufficient.
Here's my method:
1. As soon as I'm done the last water change I fill the water change tub back up with fresh RO/DI water, add salt, add supplements (calcium, potassium, and magnesium) to get them at the right numbers. I use a 20 gallon Rubbermaid tub and a Mag 3 to mix.
2. In 24 hours the water is ready in case of emergency.
3. Unplug return pump, powerheads, and ATO. Leave skimmer running, but take cup off (it will overflow when I refill sump).
4. Siphon the detritus out of the overflow, then use a pump to siphon the detritus out of the sump. This goes into a bucket.
5. Use gravel vacuum to clean all of the sand. Pinch hose every once in awhile to let sand settle out of the tube instead of getting sucked out into the bucket. It is inevitable to suck some sand out. It is usually a full 5 gallon bucket to clean the overflow, the sump, and the sand.
6. Let detritus settle in the bucket, pour off the water into the drain keeping sandy detritus. You can either scoop the detritus out into the garbage (you don't want the bits of sand in your drains) or do what I do which is; refill bucket halfway with tap water, let it settle, and pour it off again. Then refill bucket and pour it all onto the garden plants. You can skip this step.
7. Once the sand has all been cleaned, I setup a drain hose to a floor drain and drain out the rest of the volume. I change 10 gallons every week or 15 gallons every 2 weeks...whichever happens.
8. Hook drain hose to Mag 3 pump that's in the tub of new saltwater. Pump new saltwater into the sump. When the sump is almost full I turn the retun pump back on. The return pump is faster than the Mag 3 so when the sump is empty I unplug it, and let the Mag 3 catch up again. Once it's full the return stays on, and I plug the ATO and powerheads back in. I put the skimmer cup back on.
Voila.
10 minutes.
FWIW, I use vinyl hose.