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Re: 135gal set up
- To: <Aquatic-Plants at actwin_com>
- Subject: Re: 135gal set up
- From: Thomas Barr <tcbiii at earthlink_net>
- Date: Tue, 08 Jan 2002 12:17:54 -0800
- In-Reply-To: <200201080848.g088m3Y14012 at actwin_com>
- User-Agent: Microsoft-Outlook-Express-Macintosh-Edition/5.02.2022
> 1 - CO2 Controller: You said this:
> "Drop the controller part and use the probe as a monitor
> and run the CO2 at a constant rate. Also, pH in the sump
> will much lower than in the well run tank. Check to make
> I'd not dare to argue with your knowledge (grin),
Well generally expect everyone to question things. I expect it. I'm not one
of those folks that dislike to be questioned(how dare you question
It's the logical flow IMO. Gets you thinking about the issues and seeing the
but this scares the heck
> outta me, mostly because the use of CO2 is so relatively new to me (I had a
> Carbo Plus only up until 3 months ago). Is there a "setting" I can use to keep
> my CO2 bubbling WITHOUT causing too deep a pH swing or suffocating my fishies?
Certainly, all the pic's of those Discus tanks somehow struggle and manage
just fine:-) A controller will not solve this issue for you. I've seen folks
kill fish with and without a controller. Amano has done it himself. I have
yet to kill any fish with CO2 but I did say fish, shrimp I've killed. It
will not be the pH swing but the CO2 toxicity. If you keep your flow rate
constant by using a needle valve and bubble the CO2 gas into the tank a5t a
constant rate. This forms a CO2/HCO3 buffer system that is pH dependent.
Keep the pH steady and you keep the CO2 steady. KH doesn't evaporate and
unless there's very little KH or your CO2 is very low remains very stable
with regular water changes. (HCO3 = KH). Don't add any other pH buffers
beside baking soda etc.
Main thing is to dial the pH using the gas to 6.6 or so and it might rise to
6.8 6.9 if thi9ngs are growing well near the end of your lighting cycle.
That's not a bad range. + or - .2 pH units is good and decent target to
With a wet/dry and good circulation I've never seen poor results with a CO2
system or high variability in hitting targeted pH ranges. You have good
mixing and less build up of lethal levels of CO2.
A pH controller set up has to be set at a higher rate than a non controller
system but virtue of its throttling of the on/off cycles. The ON cycle has
to be fast and intense enough to catch up to the set point.
In simple example terms:
If you set up a constant non controller system: Bubble rate is 3 bubbles a
second. This yields a pH of 6.7. The rise through the daily cycle is .2pH
unit. Great, this good.
If you set up this same system with a controller you'll need to set the
bubble rate at 5 bubbles a second to make up for the time the unit is shut
off. If you set it at 3 bubbles a second it can NEVER catch up to the set of
ranges you programmed into the unit. It will be like the continuous non
controller system then. A solenoid shuts the unit off when it's reached the
set point. As the pH rises back up it opens and lets more CO2 in.
What happens if the solenoid gets stuck(set at 5 bubbles per second?)?
What happens if the pH probe gets knocked out of the water for any reason or
is not calibrated/becomes imprecise?
Now consider the constant rate method: A pH probe is still used but it just
for monitoring. Nothing will change unless you actively change it.
No solenoid to buy or break or plug in. 100$ cheaper plus solenoid cost.
Accuracy is the same as a constant CO2 method.
Needle valves are very good simple mechanical devices that do great. Cheap
ARO valve suck but for 19$ or more you can use all sorts of nice all metal
valves that work great for years. IME most valve drop off the flow, not
increase it. If something goes wrong, generally it means not enough CO2 for
the plants which poses no threat to the fish and can corrected for without
harm to livestock.
A solenoid will save CO2 by turning the CO2 off at night which I do(but do
not use a solenoid) but it's not needed. CO2 gas is pretty cheap.
> I admit that I still have a lot to learn in this area.
So do I:-)
> Currently, I buffer my kH up to 3.5 with Baking Soda, and use CO2 to bring the
> pH to 6.6 using the controller.
> Also, what are the factors that make pH in the sump lower?
Well think about it. The sump is where you have a small area with great
mixing and the CO2 inflow. The tank is where the CO2 is being used up and is
much larger and slower flowing. Where are your plants? The sump or the tank?
That's the best place to take the reading but there will be some lag time to
get the pH up after turning it up or down etc. This becomes more true as the
tank gets bigger. Well mixed water helps solve this problem among others.
>Is this a lighting
> issue, or just the oxygenation that occurs from tank through pre-filter?
> 2 - UV: You mentioned that I might want UV for a day a week.. Is there any
> harm in doing what I currently do; Run it 24/7, other than having to replace
> the bulb more often? (hopefully not a silly question).
Some have argued that it removes the iron chelation (perhaps other trace
chelated metals) from the water. I think it's a waste really and letting the
natural system run it's course works fine. The advantage to running it once
in awhile is that after a cleaning and disturbing the tank, all sorts of
algae spores etc are suspended. This kills those off well and other suspend
animals/bacteria. It takes a while for them to build back up (a week or two
is fine). GW can cause problems for new folks. I think the way your
approaching it well be clear of GW though. Unless you over feed/add too many
fish in the tank(no more than 7-9 adults) your fine.
> 3 - Wet/Dry - Micron Bag Filters: I'm afraid I plead ignorance on this one.
> Are these things that go into a sump in place of bio/balls, or is this a
> different kind of filtration (like the Rainbow systems)? Or possibly a
> pre-filter item?
It's simply bag lies like a coffee filter that hangs about your sump. You
can remove your wet/dry section and have this only or you can have both.
It's up to you.
> 4 - Outflow: You said:
> "The return would run a spray bar along the bottom back wall
> (make sure to drill a small antisiphon hole in the return right
> below the surface of your tank's water level!!)."
> Bottom back wall.. Near the gravel level
> spraying up?
No horizontally towards the front of the tank.
> Also, this antisiphon hole I suspect is INSIDE the tank rather than outside,
You got it. Do not forget this item. It will screw you if you delete it.