Filter flwo question

Turning down the flow will reduce the turnover of the tank--the biggest impact would be if this also reduced surface agitation and reduced gas off. The bacteria in the filter should still get enough oxygen and food from the lowest setting available. One other issue that you won't see until you add fish is that the slower current allows more waste to sink to the bottom instead of being captured in the filter. Some movement of the plants is good, and will prevent solids from settling on them--is this enough to actually move the base of the plant, bend it over, or just cause some swaying? If it's not moving the plant or bending it over, I'd leave it as is--and if it's bending the plants over, I'd maybe just move them. While the fish you intend to stock will determine how much current you really need, my experience is that more current is usually better than less. Very few fish have a problem dealing with currents in the tank.

I am guessing this is an AquaClear 150? If so, the numbers have changed around slightly, but that isn't a big deal. Anyway, if it is an AC then yes, they are pretty powerful. You could probably turn the filter down slightly, but I would think if you have a sufficient amount of gravel in the tank it should be OK.