Not sure if you're still on here, but I'm running into the same issue with the same tank. I've done an insane amount of research and comparisons and I'm struggling to wrap my head around it. Came across your post here and I'm relieved I did, however I'm struggling a bit to comprehend what you did and what is connected to where? The stock tank has the check valve where the capped off valve is, and the ROV where the brass AN fitting is. The C/V must be connected, is that what your blue fitting is? Why'd you choose to leave the other one capped off instead of using it? I'm going to call the company ASAP, but I wanted to see if you could provide some insights, as you experienced this.