borax...

[pov]

Does anybody use or is familiar with using this with tropical fish , I hear there are lots of health concerns that are controversial. its banned as a food additive in the US and a small minority but is still very very common, in 2 minute noodles and caviar just to name a couple.
as a Water-softening agent-
Borax alone does not have a high affinity for the hardness cations, although it has been used for water-softening.
Its chemical equation for water-softening is
Ca2+ (aq) + Na2B4O7 (aq) → CaB4O7 (s)↓ + 2 Na+ (aq)
Mg2+ (aq) + Na2B4O7 (aq) → MgB4O7 (s)↓ + 2 Na+ (aq)
The sodium ions introduced do not make water ‘hard’ !!!.
This method is suitable for removing both temporary and permanent types of hardness.

 

[Colin_T]

It's poisonous to all aquatic organisms.

 

[pov]

figures , what about in the water before you add it to your tank , treating hard water.

 

[NickAu]

Well Muriatic acid is also extremely toxic yet Discus breeders use it to lower PH.

 

[FishGuest5123]

I use To use it in my carpet to kill fleas. It not only killed the adults, but also made any eggs that hatched sterile. I wouldn’t use it for anything but laundry.