Bubble counter

[Dave S]

I've recently set up my new CO2 system, and I am at a loss to understand why
I need a bubble counter! Can I just count the rate of bubbles in the water?


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Dave Scott
Hampshire, England

Beware spam trap when replying

[Nikki Casali]

Dave S wrote:
> I've recently set up my new CO2 system, and I am at a loss to understand why
> I need a bubble counter! Can I just count the rate of bubbles in the water?
>
CO2 needs to be given time to dissolve into water. CO2 will dissolve
more easily if it is broken up into minuscule bubbles first and given a
long route to the surface. It's difficult to gauge the rate from those
microscopic bubbles.

You can bubble CO2 directly into water from the end of bare tubing
without diffusion, but the large bubble will head straight for the water
surface. It will break the water surface and escape into the atmosphere.
Most of that bubble will not have dissolved.

Most diffusers have built-in bubble counters which allow the bubble to
be counted first before it is broken into smaller bubbles. On the other
hand, I got rid of my diffuser and now bubble the CO2 directly into the
filter intake. This means I can count the rate of bubbles without a
bubble counter. But the difference is that the CO2 bubble is sucked up
into the filter intake, smashed into tiny bubbles by the impeller,
pulled through the whole canister filter system and finally ejected from
the output hose completely dissolved.

Does that help?

Nikki

[Ozdude]

"Nikki Casali" > wrote in message
...

> Most diffusers have built-in bubble counters which allow the bubble to be
> counted first before it is broken into smaller bubbles. On the other hand,
> I got rid of my diffuser and now bubble the CO2 directly into the filter
> intake. This means I can count the rate of bubbles without a bubble
> counter. But the difference is that the CO2 bubble is sucked up into the
> filter intake, smashed into tiny bubbles by the impeller, pulled through
> the whole canister filter system and finally ejected from the output hose
> completely dissolved.

I used to feed mine straight into an air stone in the bottom of an internal
filter, but have since changed over to a combination bubble counter and gas
exchanger, in the form of a 375g (gramm) jar, half filled with water.

It allows the bubbles to be counted before being broken up later by the
venturi, and I feel a little safer having the gas buffered by a small water
bath before hitting the tank proper. It seems to have worked because the
diatom thing has clamed right down since doing this.

Going off my pH drop from 7.8 to 6.8 and KH readings I now know how many
bubbles per second equals what CO2 ppm in the tank - at the moment with 3
bubbles per sec and a KH of 5dKH (89.5ppm) I am getting 15ppm CO2 which is
spot on apparently for my bigger tank. I wouldn't know this if it wasn't for
the bubble counter being part of the equation ;)

Oz

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My Aquatic web Blog is at http://members.optusnet.com.au/ivan.smith