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Re: carbo plus vs co2, plants melting

Hans at schaare4 at earthlink_net wrote:

> I worry about leaving the Co2 on all night because of the fish. Is there a
> safe starting point to do this without killing fish? I'd like to do away with
> the aeration but i worry about the fish.

Bottom line is, you need more CO2 if you expect it to benefit your plants,
so stop worrying and learn to love the CO2 bomb.

If you're worried about your fish, then choose a weekend night to turn off
your aeration, then get up and monitor the thing every couple of hours thru
the night. If your fish start gasping at the surface (which I doubt will
happen), turn it back on. After you get rid of the aeration and catch up on
your sleep, eliminate any surface turbulance from filter return, etc., then
gradually increase the CO2 injection until the daytime pH drops to around
6.8. Then brew a strong pot of coffee and leave the CO2 on 24/7, monitoring
the pH throughout the night if you're afraid of it getting too low before
morning (again, I doubt it). Once all you're stress dissipates, gradually
adjust the CO2 until you find a happy medium between day/night pH levels. I
bet you can keep it 0.2 or 0.3 degree range (e.g., 6.6-6.8, or 6.7-7.0,
etc) without even changing the adjustment.

> Question, if i do inject Co2 24/7, and i assume the ph will go down (here the
> tap water ph is 7.8 to 7.6) when i do a water change the shift in ph may be to
> great and kill fish, i have a fine collection of rainbows i have become quite
> fond of among others.

If you change 10-15% of the water at one time, the pH won't change enough to
hurt the fish. One of the resident chemists can probably tell you how much,
but I'm too lazy for that. If you wanted to be super gentle to the rainbows,
then add the water gradually with a ladle or large spoon over the course of
several hours. :D  Seriously, just do smaller, more frequent water changes
if you want the pH to remain more constant.

Once you get the CO2 to 15-30 mg/L, the oxygen level in your tank's water
will be as high or maybe higher than with aeration, as long as nutrients are
in abundance.

Dan Dixon