Well shoot man I am really sorry.
Can you snap a picture of it?
Can the plug be drilled out, and replaced with a bulkhead? I suppose doing this there is no turning back though.. But what I was thinking is you put a bulkhead on it then a pipe with a valve that you can close. Then you can use this for water changes, just attach a hose to the nearest floor drain or something like that. Or just a bulkhead with a plug.
I noticed a couple weeks ago that UFA moved. Used to be they were just off Macleod by 42nd Avenue. Not anymore. Just checking their website, looks like the agricultural division moved clear out of town. There's one up in Airdrie and another in Strathmore. Oh and High River. Stellar.
http://www.ufa.net/locations/LocationLanding.html