Originally posted by reefen
I have a tank that is 3 1/2 feet deep
Deep meaning tall? Wow, that's a pretty tall tank. Even then I would think that 400 watt MH's would be able to support shrooms on the bottom. My limited experience with shrooms is that they shrink up when there's a lot of light. I would try placing some on the bottom of the tank in a shaded area and some in a lighted area.