Hi. new member here, but I've been lurking/reading for a long time. I'm an old-school bromine portable spa guy since the early 1990s.
First I'd like to thank the authors of the stickies here, and for the opportunity to join the discussions and for the chance to learn: There's some great info (and members) here. In particular, I'd like to call out a couple of important learnings for myself, and ask some related questions:
1. Use sodium hypochlorite as the oxidizer of sodium bromide. who'da thought! I'm historically (or hysterically perhaps) entrained in the world where di-chlor is the only permissible form of chlorine that a portable spa will tolerate. Thats essential advise for spa stores, to be sure, but its good to know that one can use cheaper alternatives at least when the objective is to form HBrO, not HOCL. Nice "ah-ah" moment for me, thank-you. Anyway, the sticky also expects this to be a one-time motion, though, and assumes the daily use of a floater and tablets -- which are just sodium bromide + <some form of chlorine>
Don't hold this against me but I've been content with the convenience of one-step "brominating" granules (mixture of sodium bromide and Di-chlor) because I get that at start up you have a chlorine spa until you build up enough salt reserve. For me that is a don't care, and frankly I don't get why the one-step approach gets such a bad rap. My only issue with using "brominating granules" is that towards the end of the drain interval you have a larger-than-necessary bromide reserve, although for all I know the tablets do the same thing. Anyway, I've proven the "reserve" thing by using straight dichlor for the oxidizer which still produces a good HBrO conversion. So: problem solved by using straight dichlor instead of the mixture. I have both in my arsenal.
I'm just not a floater kind of guy. I don't like the risk of high localized bromine concentrations wherever the floater may end up, risking my shell, cover, pillows, etc. and I dont' like things floating around in my tub unless its my grandkids playing with their toys. But it could be that I'm just a control freak lol -- I just don't mind adding the salts and oxidizer myself, vs. letting some compressed form of the same thing dissolve at its own rate.
Actually, Im toying with the idea of a different approach:
1. Adding initial bromide reserve (pure sodium bromide)
2. Shocking with something initially (MPS, Dichlor, Clorox...)
3. using straight on a daily basis, adding more reserve salts only when needed. I guess I don't see the need to add salts every day -- or am I out in the weeds here?
I can use my nose to determine when it is time to add more salts. In such an approach, however, the choice of (daily) oxidizer is interesting: MPS leaves no sanitizer behind (if the reserve is depleted), but Dichlor will. Also, MPS is about $3 a pound and Dichlor is about $7 a pound, but I'm not a chemist: Are these two oxidizers pound for pound equivalent in terms of producing the same amount of HBrO from the same reserve bank?
Liquid Clorox may be cheap, but the risks are way too high (for me) using it as a daily oxidizer. First, there is the chance of spilling on the cover, filters, pillows, or shell. Second, if the bromide reserve is depleted, then you have introduced an unsafe form of chlorine to the spa. MPS and dichlor are much safer choices it seems to me, in this situation.
2. use borax to raise pH instead of Spa up. This is a great tip! It also begs the question: Spa chemical companies re-package baking soda and call it "TA increaser", so why hasn't someone put 20 mule team borax in a 2 lb bottle, tripled the price, and called it "the safer spa up"? Actually, I've used the soda ash by carefully considering the effect on TA as well, but this tip is a great ah-ah moment for me, and I'll probably be adding borax to my arsenal now :-)
Thanks again for the opportunity to join the forum