Hoping to hook up my acid and chlorine injection pumps this weekend, and while the best return point for the chlorine seems obvious, (the floor cleaner heads, since that way the new chlorine will be swept over all the plaster surfaces first), I don't think I want to put acid over the plaster, not to mention the springs in the heads themselves. I really only have two other convenient (piping at the pad) choices: four floor returns that are distributed along the long axis of the bottom, or six bench jets that have omni eyeballs but generally shoot straight out into the end of the short leg of the L. (I suppose I could use the fountain line and have the acidifed water shoot through the air and land in the middle of the deep end, but somehow that just seems like a bad idea...) The floor returns seem like the best path, but the current fittings are omni cone/slots that may not keep the incoming acid far enough away from the plaster, I haven't felt the flow direction yet. What do you think, gurus?
Also, the nice-looking injection fitting that came with the pumps is .25 NPT, which will require me to drill a .44 inch hole, then tap it, and I'm just wondering about the width/depth of such a big hole in the PVC. I've got a 2.5 inch elbow available for the chlorine, but only 2 inch for the acid; any experience tapping that size hole in PVC?