I'm not quite done yet but thought I'd share what I have so far. I'll try to post a few pics. I'll start with the parts list and a rough idea of prices.
90$ 1/3 hp sump pump
50$ clean 300g water tank. (I've found these. cheaper but they have some kind of dye in them that won't come out.
1 4way tee
9 tees with the center outlet being 1/2 inch
1 threaded bushing for the pump to connect to Pvc
9 bushings, 1/2 inch to connect shower heads to tees.
50$ roughly for all Pvc fittings
30$ for 9 shower heads
Total about 220$$ so far. I wasn't sure if this would work so I'm going to add a union and valve to control pressure near the pump and an auxiliary sprayer on a hose. Also going to use a milk crate as a box for filter material. This will bring to to about 250-260.
I think a 1/2hp pump would have been plenty. The pump I already had laying in the garage but I think it was about 90$ new. I'm going to ttry to add a few pics. I also had to drill out the shower heads to make the hole bigger as I wasn't getting enough water and no pressure at all. I'll try to show that too.