My vote is for the most exotic, but strongest (and potentially expensive) option. Steel frame with magnetic decorative panels to cover everything. You're talking about housing expensive livestock, in caustic water that has the potential to ruin a large chunk of your house if it fails catastrophically. When you factor in your time/materials for a DIY like this, (IMO) you end up at or exceeding the cost for a professional to build you a simple steel frame. You can always add in the decorative panels later to cover up the guts. My 2 cents...good luck with whatever route you pick.