Am trying place an indoor lap pool on a patio slab on grade. Pool requires 220lbs/sq.ft. Pool is 14'-0" x 8'-0". Slab will be placed over compacted sand to 2500psf. Will a 6" slab with a mat of #5 rebar 12" OC ea. way, with 6"x6" 10/10 wwm. be sufficient? Slab...