Don't do that, George!
It's not as if your new aluminum tank is gonna explode if you use it...it'll last at least as long as the previous (original?) tank, and from what you've said, you need it inside your marina. So keep it, and let's find a location for the L/S...with a y-valve in the head discharge line to let you choose between 'em. To find the specs, go to the Raritan site http://www.raritaneng.com to products, waste treatment, then click on Lectra/San. On the left side of the page you'll see a list of documents in pdf. The dimensions are in both the promo sheet and the manual. When installing it, follow ALL the directions VERY carefully. Btw...there's a brand new L/S MC for sale on eBay right now (also a very old one--never used, but avoid that one anyway). The price last night was still a bargain. Go to ebay, then enter search term "marine sanition."