Baquacil for hot tubs if fine as far as you scale the dosages based on water volume. Simply use the amount on the label (i.e, so many ounces per many gallons) scaled down for your spa volume.
I recommend using hydrogen peroxide as an oxidizer in addition to the Baquacil that is there for sanitation.
ALSO SEE: Alagecide vs Shock
Baquaspa vs. Baquacil
The differences between Baquaspa and Baquacil is the concentration. Asides that, they pretty much contain the same thin, Hydrogen Peroxide.
|Baquaspa shock is 7.5% concentration||Baquacil shock is 27%
|BaquaSpa works best for heated water||Baquacil works best for (cold water) pools|
|It actually costs more in the long run||More cost effective in the long run|
|Where to Buy: bUY ON AMAZON||Where to Buy: AMAZON|
That means you can use Baquacil and only use 2 oz for approximately the same dose as baquaspa at 7 oz, and yeah you can substitute one for the other.