Thank you! I am enjoying this tank a great deal. Not finishing it up yet though.
This tank is reef ready with a trapezoid overflow box centered on one short end. It has a 2" bulkhead and two 3/4" bulkheads. I am using the 2" as the main drain, one of the 3/4" as the emergency drain and the other 3/4" bulkhead as the return from the CO2 reactor. The main drain has a Poret foam block with a hole carved out of the center as a prefilter. Having an open drain with a ball valve, not such a good idea. Didn't check to see how large the opening is in the ball valve when the drain is running full but not sure fish that fit through the skimmer teeth can fit through the partly closed ball valve.
It worked out that outside the stand plumbing is PVC and under is mostly tubing. I discovered that hose clamps aren't just screw end but also hex so found a wrench and leaks don't stand a chance now.
Back to Reef Central to research pumps and I ended up with a pond pump - Laguna Flo-Max 1500. I am using the Laguna and the old main pump, Rio 2500 for water flow. The Laguna's return goes outside the stand and up the overflow end of the tank and is painted black. A true Y splits the return and there are two simple PVC elbows serving as returns coming in through holes drilled on the top panel of the tank. The Rio is plumbed through the bottom of the tank and is running the 20" Cerges CO2 reactor. If the output has no head then it looks okay on paper, 1500gph+780gph and not even too bad at 4' head of 1320+430gph but the truth is probably more like half that what with the inevitable turns to fit the thing together.
For some reason the Cerge's is working better now than it did going up and over and with 6' of horizontal pipe like in the 8' tank. I have its output on 6" of Loc Line pointed at about 45* down and diagonally to the left rear corner. The Black Neon Tetras adore the big 1" returns and half the time are schooling near one or the other of them. I have some extensions I can put on them and may as the fish tend to explore and I am hearing some slurps as the fish hit the skimmer teeth and escape.
I can see debris moving steadily towards the skimmer and all the plant leaves seem clean and gently moving. There is quite a ripple on the tank's surface and somehow the left end is perfectly clean. Not sure how that works with the strong ripple from the right and the skimmer also on the right but it seems to be doing so.
The sump has two drains, one 2" and one 3/4" emergency drain. The 2" drain is causing quite the ripple in its section of the sump. I may end up drilling a number of holes near the bottom to diffuse the flow more. The 3/4" drain is just dumping straight down into the return area but I will add bits of hose and elbows so it drains to the drain area soon. Running two 200 watt heaters as before and the pumps have prefilter sponges on them as before. The filter media is the same, the original sump sponge plus some scrubbies sandwiched between a 4" 10 pore per inch Poret sponge and a 2" thick 30PPI Poret sponge. I cut a piece of sponge to make pads to dampen the vibrations of the pumps and it sure helped. At the moment I do hear a hum and water falls through the skimmer teeth, not bad. I will cut a longer 3/4" pipe so I can raise the level of the water in the overflow box at some point.
There was a platy in the overflow so I pulled up the emergency drain to flush her down. Not a great idea. I couldn't see where the pipe went in and the emergency drain blew all sorts of mulm into the return pumps so the tank was cloudy and I don't even see the platy in the sump! The tank was mostly clear inside 15 minutes and when I returned home in an hour the tank was again crystal clear. Wow.