There is always a way, just depends on what you are willing to do. I don't know what tank your talking about, glass, or acrylic. When someone comes to me for a build, I insist on at least 1 primary drain, and one back up. Nobody has come back saying they wanted their money back for a bulkhead and a few dollars worth of PVC. I have a 75 gallon that will be at a trade show, and I practice what I preach, 2 small OFB's, dual 1" primary drains, with 1 back up 1" drain. We will be looking at about 500 gph, and will have a Herbie (Gregory) style gate valve set up.
I'd say drain it if you have to, and get it dialed in plumbing wise. Like I said, it is up to what your willing to do. J