I do a gravel syphon once every 6 weeks aprox. There is only a thin layer of gravel so even when I do it not much really gets pulled out. So between doing that and cleaning algae with the mag floats every week or so and changing the filter bags every week, maintainence is now a breeze.
List of stuff used
Toro 4 valve sprinkler timer from Home depot $30
Toro 3/4 sprinkler solenoid valve $12
Sump pump float switch from Lowes $20
small water pump I had that hooks up to float switch
Misc. copper and pvc pipe.
I originally designed it where it was supposed to drain manually withput any float switches, There was a chamber that wasa going to fill up in the sump and when fresh water was added, the sump level would raise and water would flow out of a bulkhead. But the glass in the sump cracked so I had to do the float and pump setup.