Linking tanks, to share the same water

[ReefLoverrHS]

Hello, everyone! I am new to this site, and just joined. Awhile back, I tried attempting a project to have 4 tanks (3 ten gallon tanks, 1 thirty gallon) all flow down to one 10 gallon sump. I did not succeed, and have a problem with it. I'll get to the problem in a second, but first I will give a little info on what I have:
I have three 10 gallon tanks sitting on a top shelf. They have 3/4" flexible tubing, with a strainer on the end of the intake tube, to prevent fish from being sucked in. The intake tubes are completely run on gravity. About halfway from the tank to the sump, I added a ball valve, to stop the flow if ever needed. In the 10 gallon sump, I have a heater, and return pumps (370 GPH, bought off of Ebay http://bit.ly/1kFPXuM). As for the 30 gallon tank, I have a pump (same type) as the intake, because the sump is right next to it and I can't use gravity.
OK. Now for the problems....
whenever I turn on the pumps, and open the intake valves, the same problem occurs. The tanks will either drain too fast, and the pump can't keep up, or it will fill up too fast, and won't drain fast enough. (Either the ball valve is not letting enough water through, or too much is passing through) And the problem with the valves is... They're difficult to turn. I can NEVER get it to match the waterflow. They're difficult to open and close, and impossible to get correct. I have stood and watched these tanks, to see if the intake and outtake match.. And it would seem fine... But then, out of nowhere, one would start draining too much. One other problem I have is.. The 30 gallon tank always drains too fast. The intake pump drains too fast, and the outtake pump can't keep up. (I think its because the tubes are different sizes... Oops..) I really need help correcting these problems. I really, really want this system to work. I am trying to have all of these tanks connected to one sump, so they share the same water. (Note-- I DO have water in the tanks right now, but it's just freshwater.. Please excuse the way it looks. I thought flexible tubing would be easier.. I didn't think about the way it would look..) Pictures below. My computer isn't uploading for some reason, so I just took screenshots of them

http://prntscr.com/3mxjgi

http://prntscr.com/3mxju4

http://prntscr.com/3mxjy7 <-- Tried pinching the tubing, to reduce the flow going to the sump from my 30 gallon

http://prntscr.com/3mxkb9

http://prntscr.com/3mxkr4 <--- Return pumps

http://prntscr.com/3mxkyl

http://prntscr.com/3mxl1c

Someone PLEASE help! I am thinking about going to PVC piping, and throwing out all of these messy flexible tubes. But I still worry about what to do, because the tanks will either drain or fill too fast... Help!

 

[ca1ore]

Sorry to say that the way you have these tanks setup is not going to work. Typically, tanks draining into a sump use an overflow, not a siphon. The former self-regulates (for the most part) whereas the latter does not. Generally joining multiple tanks to a single sump is not a problem as long as you have a proper gravity overflow on each tank - either a stand-pipe, overflow box or HOB overflow. In the first tow cases, holes drilled into each tank are necessary.

 

[RocketEngineer]

Problem 1: You need to do more research. Specifically, you need to understand how an overflow works because right now, you don't have overflows you have siphons that won't automatically start after the pump goes off.

Problem 2: You need to replace that shelf. From first appearance it is laminated particle board which will absorb moisture over time and eventually fail. Solid wood would work best, especially if it is primed.

Question 1: What is the intention of this setup?

 

[Mpy]

if you want a constant water level you need some sort of overflow system. You can make one with a DIY PVC overflow, or you can drill the tanks and have an overflow that way. A lot of people have issues with 10 g tanks breaking when they try to drill them which may be problematic, and a lot of people really dislike PVC overflows. As RocketEngineer said, you really need to do more research and figure out what exactly you want.