Re: CO2 concentration

> From: David Whittaker
> Subject: Peculiarities of Webb-Kelly tank
>                 Water Parameters
>                Before       After
> KH (TETRA)      2.0/2.5      3.0
> pH (TETRA)      6.4          7.2
> CO2 injection   x/3 sec      x/2 sec  where x is 1 bubble
> The substrate has a layer of fine clay and vermiculite through which the
> water passes. The DIY CO2 generator seems to be producing enough CO2 and
> there appears to be no leakage in the bottle, tubing, or connection to
> the Fluval which is submerged. And the gas seems to be dissolving. But
> the pH will not drop and the plants are not growing as well as before.

Try putting a small amount of the suspected clay in distilled water and
measure the pH after a day or so. You should be able to measure an increase
in hardness if that is the case. As a test for your CO2, pull the airline
off the spray tube and hold it underwater. It should release a bubble
every few seconds unless there are leaks. Blow into the tube; there should
be NO leakage. I've found silicone cement superior to epoxy for sealing
plastic tubing into the pop bottle cap. Better yet, is to use a rigid
plastic tube like the one you pull from an airstone and cement that in
and attach the PVC tubing to that. I recently caused a drastic pH swing
in an incident involving a leaking CO2 rig; the result was one dead
farlowella. :`( Plants, neons, otocinclus & platys survived. BTW I keep
platys in very soft water with my plants so don't be afraid to try it.

 - Steve