I would like to try and pool a discussion about the pros and cons of the
Carboplus device for controlling ph values in a tank. For those not aware
this is a device which claims to make CO2 from an electrolytic process. You
pass electricty across a stainless steel and carbon sandwhich and the water
breaks into H2 and O2 and the O2 is supposed to react with the carbon.
I am a chemist and find this highly unlikely to be the mechanism. In fact I
was so disbelieving that the shop assistant offered me my money back if
after trying it it did not work. However I have used the device for about
3 years and must confess it does bring the ph down. I still do not believe
in the mechanism and think it is more likely to be interaction with
carbonate in the water.

I have always lived in countries with very hard water and the tank ph runs
at aroung 6.9 with the device running wheras it has been almost 8 without
it. . However I now want to go to a true CO2 system as I am having constant
corrosion problems with the point where the cable joins the metal sandwhich.
Have others had this ? I have recieved seveal different designs and they all
fail after about 6 months usually as you change the second or third carbon
rod.

Can anyone propose a mechanism for the way this device works. In work we had
a long discussion about interference with the balance of carbonate and CO2
in the atmosphere. I have also heard that it is less effective when there is
no carbonate in the water, something which I notice as I have recently
switched to using rain water in the quarium as the carboplus was getting
coated and damaged by carbonate deposits.

Also has anyone lese had these constant corrosion problems with the device.

Pros :-
Does bring ph down
Does help plant growth (but not sure it really puts CO2 in ther water)

Cons
Sandwhich fails due to corrosion at teh point where teh cable meets the
sandwhich.
carbon rods need replacing every 3 months and are expensive
New carbon rods are very active and you need to play with setting in the
first few days until it settles down.
No good way to control ph other than trial and error.


Regards

Russell Barry
Switzerland