Hi Heather,
I have recently gone through the exact same issues as you! We got our sundance 780 hamilton about a month ago and also were using the frog serene (bromine) system. I too could never get a bromine reading!! After some research I believe the problem was two-fold. The primary issue was a huge amount of biofilm in the pipes that builds up during shipping from the test water that they don't blow out. Chlorine/bromine has a hard time keeping up with a lot of biofilm in the pipes. Another (much lesser) issue was that the frog "jump start" pack doesn't actually build a bromide bank in the water. Reading the ingredients on the jump start, it is simply a dichlor product that puts in a bunch of chlorine. Really silly for frog to package a jump start powder with their bromine product that doesn't include sodium bromide. For a bromine system to work it needs to have a bromide bank established when the tub is filled, which can then be repeatedly "brought back to life" into active bromine through the use of oxidizers such as dichlor (sometimes referred to as shock or chlorine shock), mps (non-chlorine shock) and ozone injection which our tubs have. I've found the sundance ozone on its own isn't enough to keep bromine levels up, but it does help. Eventually the yellow frog bromine cartridge will develop a bromide bank on its own via slow dosing of bromine into the water which breaks down into bromide, but that takes a while. Until there is an adequate bromide bank in the water, it is essentially a chlorine tub that will require constant additions of sanitizer. After a week of confusion and my bromine levels always reading 0, I had started adding more and more MPS shock after each use in desperation to get a bromine reading the next day. Eventually I was able to get a reading the next morning of about 0.5ppm bromine, but after a few more hours it was back to 0. Things were not going smooth, I knew something was very off. Sanitizer levels were all over the place and my sanitizer demand was through the roof (pointing me towards the issue of biofilm which I explain below). My wife also developed a rash during this period which we thought was either bacteria from having 0 bromine in the water for periods of time, or the MPS which is a common irritant.
So after 2 weeks of struggling and reading this forum I decided I needed to start over, ditch the frog stuff, and get onto the 3 step bromine process outlined in this thread
How do I use Bromine in my spa (or pool)? . I was pretty sure I had biofilm in the pipes because my sanitizer demand was so high, and we wanted to get off MPS and use just bleach as our oxidizer / bromine "reinvigorator". You will want to do a purge with ahh-some before you drain, that is likely 90%+ of your problem. You wouldn't believe how much Crud is in the lines on a brand new sundance tub. I can guarantee your chelsee is just as disgusting as my hamilton, the amount of green goop that came out of the lines when I used ahh-some was unbelievable. This "biofilm" that hides in the lines puts a huge amount of demand on the sanitizer that you can't even see. Easily eating up all of the bromine that the yellow frog cartridge can put out, and any additional sanitizer you add unless you go up to huge doses. My water was crystal clear despite this stuff lurking in the background, most owners are blissfully unaware and accept large sanitizer demand as normal.
For the ahh-some purge: I added a large shock sized dose of MPS (got it to around 15ppm bromine) and then put in the ahh-some dose as recommended on the package (it helped to dissolve the blue gel in warm water before adding to the tub). Almost immediately I got a ton of very sticky green/brown build-up that attached itself to the tub walls at the waterline (you have to constantly clean this stuff off or it will dry and get stuck on there, its really nasty stuff). I then did some follow up micro doses which I read about somewhere on this forum. for this process you don't drain the water between each ahh-some dose, you just add an additional 1tsp of ahh-some every 20-30 minutes with the jets running and air injectors on the entire time. Every micro-dose I did pulled more and more stuff out of the lines. The goop got less sticky after the first couple rounds of this, eventually being much more oily and bright green. Each time I thought it was done, then I'd add another micro-dose and more would come out. After 10!!! rounds of this nothing new was coming out so I called it good. Ideally I would have drained, refilled the tub and done another full ahh-some dose before draining again and doing the final fill, but we are in a drought area and it didn't feel right wasting that much water. I let the ahh-some infused water sit in the tub overnight and then did one final run of the jets the next morning before draining. This final run of the jets morning after did produce a tiny amount of green sludge, but nothing like I was getting the day before, I cleaned the last of it up then drained and cleaned every surface on the inside of the tub with a vinegar solution.
@Ahhsomeguy, if you see this, can you shed any light on the effectiveness of this method? I'm not sure if the ahh-some gets to a critical mass where it stops being effective? Any idea how much more effective it is to do an ahh-some purge, drain, refill, purge again, drain again then final fill vs what I did with the initial dose and many micro follow-on micro-doses using the same water?
After purging with ahh-some and starting over following that bromine guide linked above it is very easy to keep my bromine levels up. I keep a bromine floater with a few tabs in it and put in a small dose of bleach after each use (usually 2 to 4 oz of 7.5% sodium hypochlorite bleach depending on how many users and how long we were in). After exiting the tub and putting my bleach in, I run the jets (with air injectors closed to keep the pH from going up) for about 5 minutes before putting the cover on. I now wake up to bromine readings in the 3-5ppm range. When I test again at night before using it the levels have dropped by only 0.5 to 1ppm over the span of 12 hours. My bromine demand has significantly lowered since the ahh-some purge & drain. I am now slowly decreasing the setting on my bromine floater and the amount of bleach I add so I can target a level of 1-2ppm bromine when entering the tub each night. With the ozone + UVC system that we have, I think this is a safe target. Without those two systems I would probably try to keep it in the 4-6ppm range recommended here. From what I've read in my obsessive perusing of these forums, ozone is a strong oxidizer. It will oxidize some bather waste on its own, and in a bromine system it will also convert some bromide back into the active form bromine, ozone works very well in a bromine system. The main issue with ozone is it's hard to measure and therefore hard to know when the ozone generator stops working and needs replacement. UV is generally not regarded very highly among experts on this forum and others. I haven't decided if I will keep using the UV system after the bulb burns out, but I will definitely keep an ozonator in my tub.
From what I've read about bromine vs chlorine, bromine is much better for people who travel like you. With bromine you can use a floater with bromine tablets to keep the bromine level from going to absolute 0 while away. No such thing exists with chlorine unless you go to a saltwater generation system (or maybe the frog @ease smartchlor system which I don't know enough about). With my now reduced bromine usage I am confident that if I shocked the tub and turned the floater up to a high setting, I would have 1-2ppm bromine in the water after a week or more away.
