Well, I promised I'd do a thread on my overflow system using plastic containers!

This system was built using 12 Sterilite "sweaterboxes", approx. 9"x14"x6". Since the sides are tapered, the volume is not exactly what you would get from calculating these dimensions. First photo is a view of the entire system from the "backside", where the valves and tubing run water to the containers. This will also give you an idea of the size of the overall assembly.

Attach file:

---

  rack assembly.jpg (0.00 KB)

The overflow itself is not that complicated. I used a male and female 1/2" pipe thread adapters for 1/2" PVC pipe. Drilling a 3/4" hole in the bottom of the container, I place the male fitting from underneath with a metal washer so as to provide stability. Bear in mind that the 1/2" pipe thread is actually a bit larger than 3/4", so a wrench will be needed to put the washer on the fitting. You will want this tight fit!!!

The fitting is then screwed into the hole in the container. This will not require a wrench, as the plastic container is more pliable. Once in place, an O ring with a 3/4" Inside Diameter (ID) is placed over the fitting. The O ring should not be too thick, or else the female fitting will not seal against the male fitting on the rubber washer inside. The female fitting is then wrenched down onto the male fitting.

Once this is done, the overflow tube can be placed in the female fitting. The one in my photos can be replaced by a sponge filter assembly, but you'll have to figure out how to fit that on yourself. Self made sponges from raw material should not be too difficult to fit.

A short piece of PVC is place in the male fitting underneath to feed into the drain system. The drain should always be at least three times the diameter of the overflow. Also remember to angle the drain line down to the exit, to avoid areas of standing water in the line.

Attach file:

---

  male fitting with washer.JPG (0.00 KB)


  O ring three quarter ID.JPG (0.00 KB)


  O ring over fitting.JPG (0.00 KB)


  female fitting.JPG (0.00 KB)


  overflow assembly.JPG (0.00 KB)


  overflow underside.JPG (0.00 KB)


  overflow into drainline.JPG (0.00 KB)

The water feed system was more complicated. All joints must be sealed, as there is water under pressure in these lines, and any bad seal will leak. Sometimes the valves themselves leaked, and I had to go through about 30 brass valves to find 12 that didn't leak - too badly! Fortunately, I had purchased a bag of 50-60 for a song at a meeting auction. the age of the valves may have been the reason for the leaks, too.

First photo below shows the three valve grouping. These feed water via airline tubing to the containers, which then feed back into the drain via the overflow. If you think you have a big enough submersible pump coming out of the sump container, go back and get a bigger one.

Second shot shows the extremely complex method by which the airline tubing feeds water into the containers.

Attach file:

---

  water feed assembly.JPG (0.00 KB)


  water feed via tubing.JPG (0.00 KB)

A couple of extra notes:

I put the standpipe through the bottom so that I could use the T joint on top to make an emergency overflow should the strainers get clogged - and trust me, they WILL get clogged! Going through the wall, you have to remember to add some sort of standpipe for the emergency overflow. Just remember to keep the top of the standpipe below the top of the container!

Some people might want to simply drill a hole into the drain pipe to feed from the container overflow. I do not recommend this, as the "standpipe" you get using a T joint reduces the risk of splashout.

When buying the fittings, make sure you have the right fittings for the type of PVC you are using. The 1/2" pipe thread will not change, but the outside diameter of different types of PVC will vary. Half inch PVC only refers to the inside diameter.

The comment about the size of the drain line was a lesson learned the hard way. I first built with a 1" drain line, which worked fine with regular flow. However, the instant I pulled an overflow standpipe to drain a container down for removal/cleaning, the pipe backed up and overflowed even the T joint standpipes. I rebuilt using a 2" line, and could drain two of the four containers on a shelf at the same time with no splashback.

Because it isn't obvious from the photo in the first post, here's a close up of how the containers sit on the rack over the drain line. The shelves are a pair of 1"x4" boards, gapped in the middle to allow for the overflow.

Attach file:

---

  View from end.JPG (0.00 KB)

Excellent post Chrome. I finally figured out how to do the drainage system but was still stumped on the water return system. After reading this I have a much better idea now. Just one question though, where can you find the valves? I would much rather find some type of valves for the water return system at Lowes or some other hardware store so that I do not have to wait for them in the mail.

Jehmco should have the valves, they're the same ones used for large air systems. They have a 1/8" pipe thread, and I had trouble finding adapter fittings to put them into the 1/2" PVC lines. Apparently they don't make 1/8" NPT PVC fittings.

I'm not sure the size is as important as the fact that there is a valve inline between the feed and the container. When you have containers at different heights, the pressure will vary at each level, and valves are needed to adjust for even distribution.

Well I just ordered some plastic water valves from JEHMCO and hopefuly they will be here by this weekend. I was thinking of running the pvc pipe straight up from the pump and then splitting it off to each shelf. I noticed you just ran it to the top level and had all the lines running off from there. John at JEHMCO said it would also work if I just ran it to the top level and then snaked it down each level back to the sump and put a ball valve on to drain off excess pressure. Any advice on which method might be best?

A single pipe across the top minimizes the amount of PVC required. Cheap is always better for me, since DIY is primarily to save money anyway. Airline is much cheaper than PVC. I used clear hose tubing to feed from the pump to the bar; this makes the system a little more flexible than piping.

Also, snaking back and forth like that will result in increased pressure at the bottom, while the top will have considerably less pressure. The differential is much less using the single bar with the airline feeds.

check out what a guy here did for his overflows and air system.
http://okcaa.org/phpBB2/viewtopic.php?t=5393&start=90

Great thread guys; very useful for those without opposing thumbs.