Sodium Metabisulfite and H ions (H2O)

[Jackc]

Some one here is going to have to let me know if this is correct.

Sodium Metabisulfite is chemically inter-changeable with Sodium Bisulfite. When Sodium meta-Bisulfite is hydrated, it is immediately converted to Sodium Bisulfite.

Na2S2O5 + H2O ========== 2 Na H SO3

From a solution these products are inter-changeable.
Diffusing SO2 in a liquid lowers it's Ph.

This non chemically bonded SO2 is then slowly dispersed out of solution using aeration. Causing the Ph of the liquid to slowly rise.

If Sodium Metabisulfite is mixed into solution containing no H ions. No chemical reaction would take place. It then could be used through a dosing pump to lower the Ph of a system containing H ions (H2O). I am having trouble locating a solution to suspend Sodium Metabisulfite. So that it can run through a dosing pump. Any ideas on what I can use.

Can't run a dry chemical though a dosing pump very well.

 

[shelburn61]

why do you want to do this?

 

[Randy Holmes-Farley]

This is to raise reef aquarium pH? Why not just use what the masses before you have used: carbonate or hydroxide?

The pKa of the equilibrium between SO2 and HSO3- is less than 2, so there is going to be very little conversion to SO2 without there being a very, very high concentration of bisulfite in the tank water. I also would not assume that bisulfite is unreactive and nontoxic in seawater.