I been given a older ATS, similar to the SM 1000 but with no spray bar, lights, just the unit. I would like to use this on my softy tank, 3x2x2 and not heavily stocked with fish. It's a long ATS, compared to the up to date ones, but is well made. How would i set this up in terms of screen length, as don't think i need a screen which goes the full length and lighting. Thankyou,