very short intervals

[Myka]

The RedSea Wavemaker just may do the trick for you. It has different settings for gentler or more aggressive. If you were closer I would offer for you to try mine out for awhile before you decide to buy one because they aren't cheap. Why don't you use a small powerhead instead of a fan? I imagine the fan will rust in no time. MaxiJet puts out a MiniJet and MicroJet powerheads, which are tiny and have adjustable flow. The smallest MicroJet goes down to 32 gph and is something like 1.5 x 1.5 x 2". They are cheap too, about $20-25. I know J&L carried them awhile back.