Joe Sanders wrote:

I finally decided that Flourish Excel wasn't doing the best job at
maintaining my plants. No DIY setup here, I went all out and set up a
CO2 reactor, a tank w/ solenoid, and a pH computer to shut off the CO2
if it drops below 7.00.

Good for you! I also have an automated system. I also use Flourish
Excel, and I think Seachem is stretching it when they say you can use
it in place of CO2. It definitely is good to add to a planted tank
with CO2, but it just doesn't work the same when used by itself.

When you say "CO2 reactor" I am guessing you probably have an Aqua
Medic Reactor 1000. It's an OK unit, but I don't like how easily the
top and bottom screw off, and also that they don't provide you with
hose tails for larger hoses. I use 16/22 hose, so I use hose clamps to
secure the hose onto the reactor.

I hope you didn't get a Pinpoint pH Controller, those things are junk.
They have to be manually set using those little screw-knobs, and they
are SO SENSATIVE, it's next to impossible to get it just right. And
the way you set it to shut off is the most convoluted goofy setup I've
ever seen... it takes a ton of trial and error and also dealing with
the sensitive knobs **just to set it**. I got rid of mine and got an
Aqua Medic pH controller.

American Marine is supposed to be coming out with a better pH
Controller later on, but I've yet to know any details (when, how it
works, if it's better, etc.)


Plants range from Giant Valis, Cambomba, Hornwort, Moneywort,
Anacharis, and Crypts. Fish are fancy goldfish and some bushynosed &
rubbernosed plecos. Tank size is a 42 gallon hexagon.

Sounds like a nice setup. Be prepared to trim your Valis every couple
days, that stuff grows like crazy. In the wild it gets 6-8 feet tall.
Same with Hornwort.


-- I currently have CO2 going at about 2 bubbles per second. Is that
about right?

Some manuals recommend started extremely low, like one bubble every 4
seconds. However, for a larger tank like yours, 2 bubbles per second
sounds just fine. That's about what I do.


-- I have the system set to shut off if pH drops below 7.0. I
typically try to buffer to around 7.4. Does that sound like I'm doing
the right thing?

It's all a matter of preference. For whatever fish you are keeping,
just set the computer to switch off the CO2 when pH falls to the
lowest comfortable tolerance level for your fish. For goldfish and
plecos, 7.0/7.4 is great.


-- Finally, I have the system set up on a timer so that it shuts off
completely at night when the lights go out. (I have the lighting set
up on a timer as well.) It's my understanding that plants don't use
CO2 at night. Again, does that sound right?

Here's where I would say you should NOT use the timer, and instead run
your CO2 24/7. Your pH computer will shut down the injection if the pH
falls too low. If you are buffering your water (I use Seachem Alkaline
Buffer), adding CO2 will factor in to that balance, and if you shut it
off at night, the CO2 will dissipate and your pH will rise, I've seen
it go above 8.5 for some people. Additionally, your CO2 will have to
build back up in your water the next morning. Running 24/7 keeps your
setup more balanced and consistent.

Good luck!