I’ve also got the Coralbox (birthday present - wanted a GHL doser, but significant other wasn’t trying to spend that much and knew I was in the market for a doser and surprised me). For me, it definitely hasn’t been the smoothest but in the end it works a lot like
@justingraham explained. I ended up buying more tubing and check valves, and super glued some of the junctions, but still see small bubbles throughout the line. Before tweaking it, and when I had originally left the output out of the water, the air pockets were so massive it couldn’t dose anywhere near accurately and my Alk/Ca dropped significantly. After the tweaks though, and keeping the output submerged, the bubbles still show up but are much smaller, and my parameters (so far, been about 3 weeks) have been consistent but I do have to keep my eye on it for now. I’m also not sure how secure it is.. does anyone know how to change its WiFi pw from the generic? I feel like if my dog ****** of my neighbor or something he might get vengeful by looking up the pw to my doser online and force it to dump a liter of 2 part into my tank lol.