Shipping a fiberglass tank is like shipping tupperware in that you're paying a lot to move unoccupied space. What part of the country are you in? Absent the window I can get used fiberglass and poly tanks on CL because I'm surrounded by fishing industry but none of the mfg's of those tanks are anywhere close and having to buy them new would be a booger.
My observation has been that Pentair has a thicker margin expectation than their competitors.
Here's an aquaculture tank shop in FL:
We Love Hearing From You! Contact Dolphin Fiberglass Product At Dolphin, our mission is to be the partner of choice for quality products through expertise and custom solutions that gives clients unmatched value benefits for fiberglass tank solutions and interactive exhibits. Whether you have...
dolphinfiberglass.com
And another in WA:
Commercial Seafood Our commercial holding systems are designed specifically for each project. We provide the most suitable culture tank shapes and configurations for your product, and then fully engineer all the supporting equipment including bio-filtration columns, protein fractionators...
aquaticenterprises.com