Pride Plumbing came out and performed the following work: 1) replaced the charcoal filter inside a whole-house water filtration system; and 2) performed a descaling service on a Navien tankless water heater (this included cutting the power off to the unit from the breaker, mixing a bucket of water with Rectorseal Calci-Free Tankless Water Heater Flush, letting it run through the unit for about 45 minutes to an hour, flushing the heater with just water, and then reattaching the unit's skirt).