Greetings
I don't have links - I bought them from a local water softener installation company. They are 18" (round) x 40" high brine tanks and (brace yourself) cost about $100 each. The markup on them must be substantial! (they are plastic tanks for crying out loud
)
However, they are sturdy, the lids fit well, the black plastic blocks all light and they came with float valves for poly tubing pre-installed. That made connecting them to my RO/DI system a breeze. Could I have gotten by with something cheaper? Yes. But, I justified it as a long-term investment. They provide a great starting point for my efforts to install automatic top-off and semi-automatic water change systems. I will be running a line in the crawl space from the RO/DI tank to the sump for the automatic top-off and a 1/2" PVC line from the saltwater tank for the water change system. It's not completely gelled-up, but I have a pretty good Idea of how I want to do it. If you are wondering, the panel above the tanks has several switched outlets to control a heater for each tank, a salt mixing powerhead and, eventually, pumps for the auto top-off and water change system.
If you were able to find the tanks from the actual source, and not a reseller, I'm sure the price would be significantly less. I checked all of the USual PLASTICS companies and could not find a similar product.
Good Luck - I hope this helps