Brian VT

The drain is fine. A pump (or siphon) is faster.

It's very tough to get all the water out. The water that remains in the plumbing will probably contaminate the new water when you refill. Also, if you live in a northern climate, it can freeze and break things. So...when you refill...most here recommend an Ahh-Some treatment (which kills biofilm). Then drain and refill again. You won't find much love here for SeaKlear. As far as I know, Ahh-Some has no worthy competition.

It might be possible to plug the hole in the MM box by going in from the tub side? If so, then you would just need to pinch off the clear tubing where it leaves the pump "closet". Actually, you might as well pinch that hose anyway.

The likely culprit is the small hose nipple broke off the back of the MM box. It's a connector for a supplemental filler hose @ 1/4" i.d. You probably weren't able to get the water out of the MM box and it froze. This filler hose is not very necessary. Some people just plug the hole in the box and plug the end of the hose. You'll need to remove the corner skirt slats and dig the foam out to get to it. You can fill the foam back in with spray foam or bubble wrap or whatever you have handy that's waterproof. I used bubble wrap. Reattaching the slats can be frustrating. Not much "meat" there to attach.

Sodium bromide (what you added to your water) doesn't sanitize on it's own. It needs an oxidizer (chlorine, mps, ozone, etc.) to form bromine (a sanitizer). Add @ 6 fluid oz. of plain liquid bleach. That should bring your bromine up to @ 10. Wait until it drops a bit before using tub. Test and add bleach as required to maintain bromine @ 3. Shock (add bleach to reach 10+) if water starts to look cloudy.

I've read to dye the water a color so you can track down the leak. Not sure if food coloring is appropriate or if something else should be used.

If water is coming up from the screened hole in the footwell then the circulator is running (as it should be).

Hot Springs would probably send you a manual. The small circulator pump should run continuously (there is no on/off for this) and the temperature should remain constant.

If you did drain it, or if you didn't, you'll likely end up with some growth in the plumbing so I would recommend an AhhSome treatment before using it when you return. That being the case, I would leave it full because you'll need it full to do the Ahhsome treatment. Otherwise you'll have to fill it, treat it, drain it, and fill it again. I think the only reason to drain it would be if there is a chance a kid could get in there and drown or if there's a chance it could freeze.

I don't have a photo. Sorry. It was the small Watkins circulator pump that runs 24/7. There's a thin spot in the housing, near the impeller, that just wore through (probably due to prev. owner using too much chlorine). WaterWeld claims to work under water but I already had the pump out so I dried it before applying the WaterWeld.

I'd be tempted to just find a rubber plug that fits. A more-involved method might be JB WaterWeld, I used that on my plastic circulator pump housing and it's been good for 2 years.

You can ask for whatever $ you want. It just depends how badly you need/want to sell it. I just saw this ad locally. (no affiliation). I wouldn't pay that much but someone that has sticker shock from looking at new ones might. https://vermont.craigslist.org/hsh/6046380137.html

Congratulations on your new tub! The factory usually wet tests to check for leaks but I don't think the water left from that would be what you're describing. The factory certainly wouldn't have had a cover on it. I think yours might have been a floor model in a showroom. Even with a straight-from-the-factory tub I would recommend filling it with water and running an Ahh-Some For Spas treatment through it and then refill. Best to start off knowing everything (including the plumbing) is clean.

I suspect the high chlorine demand is from something other than bathing. Probably biofilm in your plumbing. I would get some Ahh-Some for spas and do as many treatments/refills as necessary until the foam shows no contaminants.

I suspect the leak is due to broken hose nipple on back/bottom of the Moto Massage box. It's fairly common. See my post with pictures here: