Re: Bubble, bubble

Greg Tong wrote:
> What is fascinating is that by early evening, the surface of the water in
> my tank is covered/packed with a layer of very fine bubbles.
> Are these bubbles then a combination of oxygen and CO2 bubbles?

Likely. I grow a lot of Salvinia (from time to time) and I find that
if there is not enough surface disturbance that a kind of film develops
on the surface of the tanks. The more Salvinia you have in a tank, the
more the fine roots trap CO2 bubbles from powerhead CO2 injection. It is
good to remove excess Salvinia from time to time as a method for
removing accumulated organic material (and constituent nitrogen etc).
As well, if there's too much Salvinia, the CO2 concentration can get
too be too high.

I also have whisper power filters running in both tanks although I have
recently removed the filter medium from these. I found it was just getting
plugged up with heavy algal growth and scuz and too much of a pain to 
keep rinsing the filter pads out every few days. They weren't really
serving much purpose as mechanical filters anyway and as biological
filters, they grow a lot of nitro bacteria and algae which is not what
I want. Now the power filters only have one purpose, to create a small,
controlled "water fall" to break the water surface. This helps to
eliminate any scum or film build-up on the surface. Removing extra
Salvinia also gets rid of the scum too.

I've done an interesting modification to each of the filters y'all may
be interested to know about. I siliconed a flexible sheet of plastic
to the out-flow lip of the filter which extends about 3" into the tank.
Water flowing out of the filter runs smoothly along the plastic into
the tank without the mini-waterfall. This reduces the amount of
surface disruption (and corresponding dissolved CO2 losses) and makes
a big difference to the amount of CO2 you need to inject. It's also
much quieter.

BTW, every once in a while, I notice a response to a post in the same
digest as the original. How do you guys read this before it comes out
in the digest format? I used to think the folks were cc'ing their
friends as I sometimes do in responding to someone in particular.

Steve      in SUNNY    Vancouver  :) :) :)