I have one of the smaller gravel vacs & one of the larger ones,
My smaller ones has a blockage in it to prevent anything from getting sucked up into the actually small tubing,
The problem I found with small light weight gems was they oft times slowed the flow down to a trickle,
Got to be rather frustrating to the point I ended up removing most all the gems from my tanks..
As you say it gets tiring having to hand scoop all that water out,
I found it worked good down to a 2 1/2 gallon size tank,,,
Was more hassel then it was worth for anything smaller, So I still hand scoop out the water from all my two gallons and under..
Last edited by Chicklet; 04-09-2009 at 10:04 PM.