Dil, I use one and love it! Couldn't live without it, actually. It cuts down on my daily maintenance and keeps the tank happy and healthy.
I wouldn't use an aqualifter for this. The guy that was going to buy mine before you wanted to use it for the same purpose and I persuaded him not to. Actually, I bought it for that purpose and learned the hard way. If this is why you want to buy an aqualifter, I would strongly advise against it.
I use a MaxiJet 600 in mine. Perfect for a 20L tank that loses about two to three gallons per week. A higher powered MaxiJet would do just fine for a larger tank, and don't cost quite as much as other power heads.
Hope this helps!