Anyone use there HPS with those ceiling light boxes that have the replaceable diffused plastic panels?
You would have the HPS light above the diffused plastic panels say 2' and the panels only inches away causing the seedings to grow more evenly like the T5 do.
seedlings are going to want blue light, so I'd recommend a metal halide if you want to use HID. And instead of absorbing the light with a plastic filter, why not just move the light away to decrease luminosity?