Upsizing to a larger tank setup so have a Deltec MC500 skimmer available for sale, which is the most common/recommended skimmer upgrade for the Red Sea Max 250 system. These are getting pretty hard to find, used it on my RSM250 before taking the tank down. I bought it used myself so can’t comment on overall skimmer age, but sticker on the pump says “18” so I’m assuming that is the manf. date of the pump at least (see pic). Works great, no issues. Just gave it a vinegar bath and it’s ready to go. $200 shipped in the lower 48.