And the overflow box has a 1" drain, it can handle 600gph.
If your return pump is pushing more than the overflow box can drain, the display tank will overflow.
I do agree that you have way too many restrictions on the plumbing going back up to the tank. It should be one clean line going all the way up, without a ballvalve. I would suggest SpaFlex tubing.
Thanks Melev,
I was hoping that the overflow box will help equal things out, right now i just have a syphon without a box. The return pump i am using is something just to get me started. Some shaft driven pond pump from lowes, the thing was $100 and flows 1300gph at 1' head. I think the manufacture was pondmaster or something like that. I plan on replacing it down the road with something better, but with 9' head there is not much out there for $100. The pump is good till 18' head but its not magnetic drive so i am learly about how long its going to last. I know that my spa has a mag pump i just replaced and it lasted about 15yrs without issue.
Melev my syphon tube is inverted inside the tank like the drain on the outside of the overflow. Is that your tank pic above? I was wondering becuase the thing that bothers me is the noise level, and judging from the looks of that picture, the system will sound exactly like mine, the waterline is only 1" or less from the drain, i can imagine that it gurgles and whirlpools down the drain as mine does making it really annoying. Am i correct?
Thanks
Now I understand the problem clearly. You cannot siphon water from the tank without a HOB overflow (a box on the inside AND on the outside). It doesn't matter what pump you buy, you'll never be able to equalize the flow between the two, even if you match it up perfectly one day. Each day the pump will build up slime, electricity rates vary coming out of the wall, the pump ages, etc. What works this minute might not in an hour. And what if there is a termporary power outage? That would be a mess.
Pondmaster pump? Some of those are perfectly fine for our systems, such as the Mag pumps. http://tinyurl.com/yr7oes For your situation, a Mag 18 with 1" to 1.5" plumbing rising up 18' would be more than enough pump, probably too much for the overflow we've discussed. Many people make the mistake of screwing on plumbing that matches the pump's threads (Mag 5 - 1/2" needs 1" plujmbing; Mag 9.5 or 12 - 3/4" needs 1.5" plumbing; Mag 18 or 24 - 1" needs 2" plumbing) which restricts the flow that pump produces.
For 9' head height, I'd get a Mag 12 with 1.5" plumbing, personally. I don't like exceeding what a 1" drain can handle. It needs to be enough flow to push the bubbles through the U tube of the overflow, but not more than the box can drain.
And in regards to your question about sound, no that box is dead silent. There are methods that can be employed to assure silence. Here's more about the plumbing (scroll down on this page) on that sump: http://www.melevsreef.com/install_sump.html
When my overflow comes in tomar i will be sure to post on how it does with the noise. Hopefully with the dual chambers it will equal the flow out. Right now i have my T fitting on the pumps return line so if i have to much pump flow, i direct it back into the skimmer section. the drain as of now is a direct line to the skimmer section. Last night i just went out and bought a 5000k flourscent from lowes which is 23W and produces 100W of light. I also bought a work light reflector to mount it in. Bulb was about $8 and refelctor $6.95. I will keep you updated, thanks for the info.