Help! My pump is too noisy

[btownbuddah]

I just finished my first batch growing with a flood tray and I'm very happy with the results. Only problem is the pump is way too noisy and is disturbing the guy who lives below me. He's a cool guy but I don't wanna piss him off by disturbing his sleep. I think the problem is only when the res is running low and the pump starts sucking air. This, however, seems to usually be the case even if I top it off every day. At first I thought I just needed a bigger res, which I do. (For some reason the hydro store sold me a 40 gal res for a 4x4 tray. The only way I can get it to work at all is if I fill it to the rim which is more like 50 gal.) But my friend tells me he had a similar problem with a 75 gal res because as the volume goes up, so does the footprint so the water level stays the same and it still ends up sucking air. This caused my friend to get evicted so you can see why I'm concerned. I'm sure this must be a somewhat common problem. I hope there's someone out there with a good solution for me.
I've got more lights for the next run so I'm reconfiguring everything anyway. If I can't find a solution that will work for sure I may have to consider switching to soil (as a last resort cause I really like hydro). Some ideas I've considered are:

Putting some sort of foam under the res to muffle the sound.

Getting a bigger res and propping up one side so its slanted with the pump in the lowest corner.

Using something like a garbage can which is tall with a small footprint. If I did this I would have use some method other than gravity to drain the tray. I'm sure there's a way but in my mind simpler is usually better.

I'm hesitant try try any of these or any combination of these because I don't really know if they would work. Honestly, I'm not even sure if my neighbor can hear the pump when it isn't sucking dry though I'm sure its worse when it is. I'm definatly doing more plants next run so I have to either find a good solution and buy another tray or rethink everything and maybe switch to soil. Someone please help me I'm totally lost. Thanks so much I really appreciate any help at all.

[stinkyattic]

I've tried tall and small footprint- runs dry less frequently; sound not muffled. I was gonna suggest laying foam board under the whole thing, and then a layer of softer foam-rubber or even several thicknesses of bubble wrap that you can get at Staples or whatever for pretty cheap. But I'd do both the board AND the soft squishy layer.
What about putting itin a different room?

[btownbuddah]

Wow that was quick. Thanks Stinky. I'll probably move in another 5-6 months but until then I'm stuck with the room I'm using. When you used the tall res was your tray above it or on the floor? If it was above the tray, how did you drain the tray? Cause if I found a good way to do that I could put the whole res up on a table or something. If this involves another pump it might defeat the purpose. I suppose I could try the bubble wrap idea and ask my neighbor if he can hear it it before I buy another tray but I'd rather minimize communiction with him.