So a little update on progress tonight.
Return pump: The slinger washer wasn't the issue, so I pulled the pump and took off the volute. Impeller was fine, but noticed a scraping noise when I turned the impeller coming from the back of the motor. It appears that the back cover of the motor had gotten jammed in on one side during shipping causing the motor shaft to scrape against it when turning. Probably happened during shipping. Fixed that, tightened the screws down on the back, removed Teflon pipe tape and put on thread sealant. Pump back in place. Powered on Golden!
Sump - Drain side: Looks like one of the bulkheads on the drain side of the sump cracked, so it's spitting water up through the gap. Of course the way it's designed with the drain chamber in the back left corner means its going to be a pain to get that one out. May just wait for it to dry out and plug it with clear silicone. Will revisit tomorrow after work.
Sump - Return side: Still got the small leak on the return bulkhead. Will seal when I drain before going salt.
Skimmer: Got a big enough set of channel locks, got the union off the pump. Lo and behold, the O-ring on that connection was missing. Must have fallen out when I took it to CoralVue a while back to get it checked and we didn't catch it. Luckily I had a union in the same size (40mm) that I bought at the same time in case I needed it, so I stole the O-ring from that. Seal is great now. Haven't turned on the skimmer, will check this later in the week, once I get the
Refugim tanks: Top tank, looks good, no leaks, have to dial back the return a bit to match drain speed.
Bottom tank, doesn't work as I had hoped. Once the common drain line fills, the bottom tanks (still above the drain) stops draining back to the sump, and even seems that small amounts of water may be flowing back through the drain. Almost overflowed it twice, so I have it shut off for now. Thinking That since this tank sits below the top tank, the external pipe I have with the cap that has the hole drilled into the top needs to be raised to match the tank on the top. I drained the water level down to the bulkhead, and will cut and extend it tomorrow evening. Found a tiny drip at the bulkhead. Will hit it with silicone once it's dried out a bit.
Common drain: I have the common drain flowing back into the center chamber of the sump through a 1-1/2" pipe, and it is putting out some bubbles. May have to address that if I star having issues with salt spay from that section since it's not covered. It's not glued where it turns to go into the sump, so it can be easily changed out with maybe a spraybar contraption that sits just below the water level or something. Bears watching later.
Tank overflows: With the return wide open, I was getting some surging into the overflows, causing them to fill, then catch up. Dialed return line back to about 75% and that appears to have stopped, and overflows quieted down. I used the standpipes that came with the setup, so they may need some work it the volume gets to me.
Didn't find as many leaks as I was expecting, so other than the setbacks above, I think I did an alright job on the plumbing. Will have to wait to run system for a prolonged period until I fix that drain bulkhead.
From the living room side the hum of the pump is noticeable. I believe that may be coming from where the return pipe is touching the mounting board where the EB8 is mounted above the pump. I'll have to take the jigsaw to that to see if that goes away. Don't need that corner of the board anyway.
I'll get a video of the entire plumbing setup at some point once I get the room cleaned up.