I changed to sand from gravel & don't have to clean the bottom much now, the corys & clown loaches keep it clean most of the time. Once a monthe (or even less often) is par for the coarse now.
When I do clean I keep the tube approx 1/2" above the sand ond wave it about a bit. That swirls the water lifting the bit much that is there & the syphon tube (approx 8mm bore) does the rest.
After cleaning the bottom of a 24" x 12" tank there is not enough sand in the pail to cover a penny (10 cents size?).
Sugarcube, do you really have to do THAT much work with sand. I was thinking once a moth was too often & I have a habit of overfeeding that I'm trying to get out of.