What is Reddit's opinion of PROZRTED Smart Instant Hot Water Recirculating Pump System 3 speed with Bulit-in Thermostat HBS24-12?

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So I looked at what they sell, and it’s not rated very highly. I’m thinking of adding a pump like this which joins the hot and cold under my kitchen sink. I’m reading that the technology of their own pump is far behind anyway. You don’t need a return line.

Hello Plumber,

I set up a circulation pump so the shower is warm with little waste during the drought here. https://www.amazon.com/gp/product/B08TQJHPXK

Is that a significant legionella risk also? It runs on a timer (morning/evening) and uses the cold water pipe as a return.