LOL. Nothing like finding stuff you can use that's been stored in a closet. It's like finding treasure!
That about doubles your total flow, to about 17X DT volume (1300+425+425+425). Good enough for softies, some LPS and few SPS.
I suggest directing the flow to about midway down the front panel. That way you push oxygenated surface water down deep and you'll get rebound flow going front to back across the substrate and rocks