Backyard Aquaponics
A place to discuss aquaponics

Hi All,
I procured 50 (growbeds)& 100 (fish) gallon Rubbermaid stock tanks on craigslist. I was hoping to use the existing threaded drain assembly for my bell siphon, but can't seem to get anything to thread from the inside. Has anyone run into this problem? Any ideas?

At this point, I am just tempted to put it the plug, drill the bottom and use a 3/4" uniseal.

Thanks,
Mike

A picture would be helpful. Some of the tanks come predrilled and some don't so it's not necessarily standard.

hey Mike...

the drain is a brass fitting..... I would silicone it up to prevent any metals entering the water and just use a uniseal in another location...

jT

I've got 4 of the 50 gallon (as growbeds) and one of the 150 gallon (as a sump) and none with a brass fitting that I can recall. I had to drill out the 50 gallon ones because all they had was a flat area with no hole pre-bored (installed through hull fittings for these). The 150 gallon tank, I can't even remember what I did it's been so long - probably just left it alone since I pump from the 150 because I'm using it for a sump.

Mike I used a 1 1/4 inch male threaded price of PVC. To connect two of them together. You might be able to
Use that if you match it up right comin from the inside. Be sure to seal that existing softer plastic seal/fitting. They are not very water tight.

Hi all, just got back from the long weekend. 2 pics attached.

the first is the factory made hole. I measure diameter @ 2 1/8", I figure I can try a 1 1/4" uniseal.

2nd is the drain assembly that screws into the hole. it is threaded with 1 1/4" but won't take a male adapter from the inside, only outside, so I can't set up the bell.

I read on another forum to take the sander bit on the dremel and hollow out the interior smooth portion of the 1 1/4" male fitting so I can glue a 1" piece of pipe into it. not sure if that will work.

If there's enough length to the thread you could probably run a tap in from the other side so you have cut threads from both directions. A plumber or a machine shop would have the tap - I doubt you'd want to buy one ($$).

TSC shows a bulkhead that might work as well, provided the OD matches the hole in the tank.
http://www.tractorsupply.com/en/store/tank-bulk-head-fitting-1-1-4-in?cm_vc=-10005

The ones I put in to my 50 gallon tanks look similar. They had internal thread as well as the external and I was able to thread connections to either side going into the internal threads without causing the parts to hit each other. I believe I used teflon tape when doing this.

edit - this fixture takes male 1 1/4 inch and is only threaded halfway through from each side of the fitting so the male threads will go in. Looks slightly different from your's, has a hex shape where yours is square. You might want to look around, I think mine came from a farm and ranch supply store.

The Rubbermaids I've had with the drain plug fitting only normally take the 1 1/4" from the outside so I would recommend probably just installing a Uniseal.
However, I would probably go at least 1" for the uniseal fitting or if you want to make the stand pipe removable, use a 1 1/4" uniseal and shove a 1" coupler into it (make sure the smooth portion of the coupler is in the uniseal once set up.) Beware the 1" coupler is a tad smaller than 1 1/4" pipe so I have seen this seep or leak a tiny bit but I have all mine installed above tanks so if they drip it isn't escaping the system.

tnx TCL, not sure I am totally following (I'm a visual guy) do you have any pics?

Mike

Here are some pics of a 1 1/4" uniseal going through liner with a plastic backing. The 1" coupler pushes into the uniseal and makes it possible to remove the stand pipe without having to keep an extra amount of water int he bottom of the grow bed because of adding extra fittings.

got it, thanks TCLynx, appreciate the pics.

Invert the factory set and use a gasket on the inside.

But then how do you connect the piping on the outside?

You could do an external siphon (inverted u) threaded into the outlet, much like the el cheapo looped hose. I know it's not the sexy bell/affnan siphon but it would actually give you more grow bed space. Just put a gravel guard around the outlet of the tank.