My water line is near the top. Most of these demo videos show a 1+ inch gap.

Will either of the MP10 or MP20's mode push the water too violently?

Tank is 2ft x 2ft x 2ft.

Thanks.

You should be fine, but how close to the top is the water level, is your tank rimless, the nice thing about the vortech's is they can be adjusted and they have different modes, you should be able to fine tune it to prevent spilling.

i have an mp40 in a 24x24x18 tank. It's not turned on all the way. However, the real question is how you'll use your vortech. If you create a single wave with it, the water will go up higher then if you use reef crest (etc). Either way, +1 on how much space you have ?

As of now, w/ my current TUNZE Powerhead. I have less than 1/2 inch from top of glass to water line.

I am okay w/o the wave. I just want the water itself to circulate better, while agitating the surface like my PH.

Would putting my vortech near the middle bottom help?

Im still curious w/ what these modes do. lol..

I think you could get away with the MP20, but the MP10 is a lot smaller. You can dial it back enough to prevent any spillage(using reefcrest or lagoon settings) and still have plenty of flow and surface agitation. I would keep it a little above the middle, this will help create a nice undertow. The nice thing is it's easy to move and tweak to your system.

I'll think about a mp20.. Thing is, in a smaller tank, seeing things rock left and right is odd?

Do these vortech do this ?

As compared to a stream where it just blows current, on a timmer.

Using the short pulse mode will cause the rocking or "wave" effect. I think it works a little better on wide tanks. I tried it in my JBJ28 and it did not work very well. I am sticking with the reef crest mode currently and everything seems to be happy.

this might help...
http://ecotechmarine.com/wp-content/themes..._manual_1.1.pdf

You're in charge. The vortech will do what you tell it to, no more no less.