Undrilling a tank

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PaulB

AC Members
Feb 23, 2005
13
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0
Preston, UK
Hi all,
I have recently bought a 2nd hand 200gal (ish) tank that I will set up as soon as I devise a method of shifting it..

As well as having a hole drilled in the corner to drain into the sump, it also has a hole drilled at the back centre of the tank. Not sure what this hole is for, but I'm not planning on using it and want to get rid. Any ideas? Can I just plug it with something, or seal a small panel of glass over it?

Worst case, I'll attach a standpipe and use it as an overflow but then I'll have the issue of trying to hide the standpipe (plus its more stuff to plumb in)

Thanks for any thoughts / suggestions
 
Having 2 overflows on a 200 sounds like a good idea to me. What size bulkheads are they drilled for?

You could always put in a threaded bulkhead and use a plug. Then it would be available if you need it.

You could also run your return out the hole.
 
Thanks for the quick reply.

Not sure on the size (I'll measure it tonight) but think think they're 1 inch diameter. Does this sound big enough?

I think the extra hole was designed for a return, but the bottom of a tank seems a strange place to put a return to me -what if the power fails?! :eek: My returns are definitly going in from the top!

I like the threaded cap idea, so think I'll go with that -the only drawback being that it wont be flush underneath, so I'll need an extra hole in the top of my cabinet (which is yet to be built).
 
Forgot to measure the exact size of the bulkhead -have set a reminder so will do it tonight.

I have a couple of powerheads for circulation, and am torn between getting a couple more, or fashioning some kind of surge device. Would like to go the surge route, but have concerns about noise and spilages.. I haven't chosen a return pump yet.

Most plans are still a little sketchy as I need to finish decorating, build a cabinet and move the tank before I start setting up pumps & building surges etc! Think I'll be making a few more posts to the DIY section :)
 
I would almost think that the bottom hole was for an underground filter run into a canister filter. The one in back may have been their return but that would be an odd place to put it... And that is assuming it was used for fresh water at one time...
 
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Sorry, I described it badly. The first hole (on the bottom, at the back left) is definitely a drain to the sump (oh and I finally measured it -1 inch diameter). The second is also on the bottom at the back but, rather than being to one side of the tank, its in the middle and is about 3/4 of an inch. I'm pretty sure now that this was used as a return.

There are some filter compartments at the back of the tank so I expect that the 1" hole was big enough (being as some of the filtration was done in the main tank). However, I plan to do all the filtration in the sump so will be removing these and guess that I'll now be needing a bigger hole -Doh! What I really need to do is move the second hole so that it sits next to the first one.. :rolleyes:

I'll cap the second one off for the moment and set up with tap water to see what kind of flow I get. If its not enough then I'll use the spare hole to install a second standpipe and get creative with screening/quietening it..

If it turns out that I dont need the second hole, does anyone know if I would be safe to seal it permamently by silicon sealing some thick glass over the top of it?
 
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