trackfast
Princess Trainer
I've been using this for about a week and a half now and it seems to be working well. I know a lot of reefers just go with an Apex, Reefkeeper, etc but I'm way too cheap to invest in something like that. This controller might be good for a quarantine tank or something that's not part of your DT. I have built heater controllers in the past but my DIY cost was higher than $22.
https://smile.amazon.com/gp/product/B01M6WMUYI/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
https://smile.amazon.com/gp/product/B01M6WMUYI/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1