In @revhtree post Q - of day he recently asked about water heaters. @Mical indicated a local LFS used waterbed heaters on their sumps. I searched the forums and couldn’t find anything so wondering if anyone has any experience with using a water bed or reptile tank pad type heaters under their sump? We had a K-size waterbed for years, heater always kept it warm with no issues. Any body use other non-conventional heat sources?