From the very beginning of this new pool project, we've had this Hayward Matrix Power-Flo 50 gpm pump set to replace the original Intex pump. After filling the pool and getting the water balanced with the original pump, not to mention using my old beehive solar heater to do a little heating, I finally got the Hayward up and running, just to see how it would perform under "normal" parameters before I start adding solar panels and a through-the-wall skimmer.
At first I had it trying to draw from the pool using the cheap Intex over-the-wall skimmer, which couldn't keep up with the pump's water demands, thus making me speed up the TTW skimmer mod. OK, fine. But the best place to put the skimmer due to water height is going to be between the two Intex wall openings. That's OK too. I've seen other mods here using a TTW skimmer between the outlet and inlet. My problem begins with the fact that I have it in my mind to switch the two, eventually running the pool inlet to the lower hole originally intended for outlet, and using the higher hole for a second outlet to supplement the skimmer. So...
Today I tried swapping the two, just one outlet from the top hole and one inlet for the bottom hole. And guess what? The top hole alone couldn't keep the Hayward pump satisfied. The strainer basket under the clear cover emptied and pressure dropped to zero. Nothing I did, including nearly shutting off the inlet valve altogether, made a bit of difference. I wound up switching them back and it went back to working properly.
Why would this be? One difference I can see is that I cut off the built-in screen that comes on the Intex fittings from the original outlet. I cover it now with one of the old blue outlet covers from last year's pool. Could that built-in screen on the top hole be that restrictive? And what about actual water pressure? Is the pressure of the lower hole that much greater that it keeps the pump fed, while the lower pressure of the top hole doesn't? And what does all of this mean for me when I get the skimmer installed? Can I keep the pump fed if I use the skimmer and the top hole? I guess I could figure out a way to temporarily plumb it that way at first to see before I did anything more permanent. I was going to cut the skimmer in a bit closer to the second outlet but I may have to just center it and play it by ear.