I'm done posting. I don't need criticized. Thank you for all that genuinely wanted to help. I was going to update so that anyone in the future that had to contend with my personal conversion to saltwater would have an easier go at it. The tech at circupool agreed that this is not an algae issue. He gave me three specific things to do.
Edited - TFP Mod
I for one hope you'll reconsider; I'll speak only for myself that I really want to help -- and would love to know what other things the Circupool tech suggested.
I think the reason some are sounding frustrated is that you keep assuming it must be the SWCGs that caused the issue. The SWCGs being plumbed in, off or on, simply don't introduce anything that could possibly explain heavy chlorine usage. They're literally pieces of plastic with some small titanium plates inside. And the hydrogen bubbles you're seeing indicate the SWCGs are generating chlorine. Unless the salt you put in was contaminated/bad somehow, it's got to be something else.
I've seen experts on this site suggest an Ammonia problem as another cause of heavy chlorine use (no experience myself) that could have been there when you opened. The good news is that a SLAM can fix that too. You have added chlorine, but I don't believe you've done a SLAM -- Shock Level And Maintain. Your SLAM level FC is 31 ppm, so to do it you need to raise it to that level, and keep adding liquid chlorine a couple times a day to keep it at that level, until you don't need to add much to keep it there. It's a multi-day process that might take 15 gallons the first day, 10 the second, 5 the third, and so on. Yes, you might go through, say, 50 gallons, and it might cost $150-200 (or more or less). But unlike traditional "shock it every week" methods, this is a one-time thing, after which we really believe you will be able to maintain chlorine levels with the SWCGs alone.
I totally get the hesitance to chase random things that people on the internet suggest -- I was skeptical when we bought our house a few years ago and I came across this site. But the principles really are based in simple chemistry science, and one of the basic ones is that overnight, with no sun or swimmers' byproducts using up chlorine, levels should remain pretty steady if there aren't bad things consuming them like algae or ammonia. Salt, SWCGs, etc, simply don't cause that loss.
I wish you the best whichever path you go on, but really hope it's here, because I for one like working through a problem to solve (and even better, a problem solved).