I can't tell from the image whether it only does adjustment in one direction or not, but if it does, it could mess you up if drift went the wrong way. Also, drift in the coco will still have to be monitored either with a ph probe in the coco or measuring runoff, so I am not sure how much work would be avoided for the price. Intriguing idea though, if you go for it, please document your experience. Just being able to dial the pH that you want in the rez would be a big plus.