That was my worry about the brushed model. I wanted something quiet and with my brushless I can not even tell it’s on.
Have you checked out the kamoer pump? Seems to have decent reviews and the people I’ve seen use it have been happy with it. If it was available at the time I bought my pump I probably would of gave it a try.
https://www.bulkreefsupply.com/fx-stp-peristaltic-dosing-pump-kamoer.html
I have a couple of masterflex 7523-80 running and you can't even tell they're running at the speeds we typically use for a calcium reactor. I have to look at the pump head moving to know that it's on. They've been tanks for me too. Have one that's been running 24/7 for two years and the other for 1+ year.
Definitely offer a lower price on eBay for those auctions that accept them. Sellers are usually somewhat motivated. I've definitely gotten them much less than what the initial offering price was listed.