Tinkster,
That is a great buy! It may be a great container. I'm familiar with those little preforms and they could be a super idea. I buried a big trash can about 8 years ago and made a lotus bog. It worked very well but a lotus growth tip did actually split the container at one of the indentions on the side (it had a series of "panels" stamped into the sides) after several years! I was surprised a lotus tuber would break a round container and it may have been a weak spot or something. Those shelves will make more of a corner for a tuber to get around, but it may not be a problem.
Looks like a good thing to try! Love those lotus!
Lori