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my current lighting set up is 1.3 wpg. i have a 46 gallon tank with a number of anubias crypts italian vals and hornwort. they're all growing ok - although the vals and hornwort arent doing too hot - but i want my planted tank to do better and i think my first problem is lighting. i upgraded to a compact flourescent system which now gives me about 2.4 wpg (110 watts).

my question is, do I NEED CO2 with that amount of lighting? I'm inclined to go for it anyway, but I just want to know if it's a necessity with that much lighting. Thanks!

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Back in the saddle!

Need - no. Well, yes, you do need CO2, but you don't need supplemental CO2. However, adding it will go a long way toward helping you have a really lovely planted tank.

-Molly
Visit shelldwellers.com!

OK, well then let me follow up...

and to the moderator who's watching, feel free to move this if it goes too far out of context

i've recently been having problems with the ph of my tank, it's gone through some pretty big swings which i cant really explain, but i think have resulted in the death of a few of my fish (went from 7.4 to 8.4, then back down, all in 2 days time...) Anyway, the loss of those fish in a short period of time prompted me to start hardcore researching water chemistry, specifically things like pH, hardness and their relationship to CO2. From what ive read, it seems that adding CO2 to a tank will lower pH, but will it add stability to the pH?

(by the way, the OTHER reason my plants may be doing so poorly could be because of the lack of CO2, when i think about it. my ph is - regardless of fluctuations - up in the mid- to high 7's, but my KH is around 5-6 degrees... so my CO2 is probably pretty low, at least according to CO2 calculators...so adding CO2 has pretty much become a necessity i think)

in other words, if i add CO2 to my tank, it will lower my pH, but will it keep it stable? I assume as long as the inflow of CO2 is steady the ph will be too, but how do you keep ph stable when you do water changes and inject CO2? wouldnt there be big fluctuations?

argh, the more i read into this the more my head starts to spin

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Back in the saddle!

what will keep your ph stable is having a high kh, which you have. i don't understand why your ph made such a drastic swing in such a short time, maybe a mini cycle of some sort? anyway, if you decide to use co2, the best way to keep the ph stable is to make sure you don't run out of co2! depending on the method of injection you use, your ph will come back to normal once the co2 stops running. if you want to keep your ph the most stable using co2, then a pressurized system is what you should have. this will keep your co2 *and* ph at a level you can regulate, as opposed to diy or a store bought kit, which must be changed every 7-14 days depending on how well you make your mix, etc.

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

Hi,
Starting with the origional tank, the reason that the
plants you mentioned started to do poorly is
probably because they had used up the available
neutrients that those specific plants needed.

One way to stimulate plant growth is to increase their
lighting as you did when you switched to the Compact
Flourscent bulbs. However, when you increase the amount
of light, you also increase their need for more nutrients
which you have not addressed.

The plant's need for the element Carbon is what restricts
their growth. They will pull the carbon from the organic
compounds (nutrients) in the gravel and water, but some
compounds don't give up the Carbon as easily as others.
(They have to "work" to do it and that "burns up" other
nutrients.)

If you are going to stimulate the plants by increasing
the watts/gallon, then you have to "feed them" and the
easiest way is with CO2. Plants easily pry the C from
the O2 molecule, and get their carbon that way.

As Moondog mentioned, your KH is fine and the addition
of CO2 to drive the pH down to a given value, will
yield a CO2 saturation (mg/l) that you desire. Try to
get a saturation value between 19 and 30mg/l. It will
make all the difference in the world to your plants and
tank.

In my experiance... When my presurized (bottled) system
runs out, the pH raises, within a few hours, by more than
one full point. If I run out of gas, then I have to take
the bottle in to be filled. They only fill on Fridays, and
then you pick up the full bottle on Saturdays. In my system
the bottle, while not immediately visable, is able to be
seen, and as such I determined that I wanted a clean, neat,
well painted bottle, and so I bought my bottles outright.
If I had "rented" a bottle, then I could walk in and swap
them much as is now done with propane tanks, and the tank
would be w/o CO2 for only the length of time it took to
drive to town, swap tanks, and drive back. These bottles
as a rule in commercial use, are hidden under counters
and in back rooms, and in general are anything but
something one would want to be seen.
So,I have two, for one system. I keep a spare
filled at all times, and when one empties, I hook up the
spare, and take the empty in to be filled. This way I
never run out, and it never makes any difference what day
of the week it occurs. When the bottle empties, I swap
them.

Frank


Last edited by FRANK at 28-Sep-2004 07:33

Last edited by FRANK at 28-Sep-2004 07:33

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

thanks for the responses

as I said, I'm all for CO2 injection, it's just that it seems like a financial commitment than I'm unable to make any time soon. Ive been looking around for DIY "hybrid" type setups, where you buy the reactor and bubble counter etc., and all you need to do is use a soda bottle or whatever to mix in the yeast and water and sugar. azgardens has a few of them. i know it would take extra monitoring to keep the CO2 level up, but it seems less expensive and a lot less intimidating than having a bottle of CO2 with those gauges and valves and such. anyone have any experiences with these types of set-ups, or do you think i'd be wasting my time?

also, would adding ferts like fourish excel help at all? i know it's not as desirable as direct CO2 injection, but would that add anything useful for my plants?

---

Back in the saddle!

Hi,
Yes, the initial outlay for a "bottled" CO2 system is
expensive. However, once spent, the only continuing
expense is the bottle refil. Here, in the Denver CO,
area, I get my 10 pound bottle filled for $9 and tax.
The bottle lasts about 8 months at slightly over 1
bubble/second.

Generally speaking, the largest capacity aquarium
that is truly managable with the DIY CO2 system is
29-30 gallons. Any larger and you need to have
two, or more, bottles in series, and a couple being
cleaned and preped. Additionally the rigid tube into
the soda bottle cap is its achilies heel as it leaks
frequently. A combination of super glue and after
that is cured, silicone glue, is about the best.

As far as adding ferts is concerned there are two
schools of thought. One is to add it as needed.
You do that by watching your plants for signs of
need (yellowing, spotting, holes, etc.) and the
other is to add the stuff, a little at a time,
once a week, after each water change.

If you do the regular fert, then you need to be
careful as the fert is just exactly what algae
needs too. If you over fert, the algae will take
off on you and you will play heck trying to get
rid of it.

Generally speaking, if you stick with a given lighting,
and plants for that lighting ( low, medium, and high),
and you stock your tank at normal or slightly above
normal levels, then the accumulated fish and food waste
products will provide a lightly to moderately planted
tank with everything it needs for the plants to thrive.
However, if you "amp" things up by taking plants above
their normal light grouping, or increase the number of
plants, or add CO2, etc, then they will use up the
nutrients as fast as they are produced. Then the
additional ferts will become necessary.

Remember that unless you use one of the "plant friendly"
substrates such as Flourite, Laterite, or Onyx, etc.
regular aquarium gravel is nothing more than SiO2,
silica, the same stuff that glass is made of. It has
absolutely nothing in it to provide for plants, except
something for them to anchor their roots in. That
means that virtually all the nutrients necessary for
plants to thrive have to come from the byproducts of
the bacteria as they process fish, food, and dying plant
wastes. It is a "balancing act" between providing just
the right amount (wattage, quality [temperature bulb in
degrees, Kelvin], and duration) of light. The right
amount of fish (low to normal stocking levels). And
regular (weekly) water changes, and the "right" number
of plants, in a given tank. When planting, it is always
a good idea to think small (few) and let the plants grow
into the tank through pruning, and normal reproduction.



Frank


Last edited by FRANK at 28-Sep-2004 15:39

-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

alright alright alright, you've convinced me to start saving up for a real CO2 unit. it's going to take me a while to get that much money saved up but since it's something i'll have - pretty much forever - it's probably worth it.

in the mean time the plants will have to deal with not getting CO2 injected with the increased lighting. that wont harm them, will it?

---

Back in the saddle!

Hi,
Nope. Won't harm them a bit. If you take a while saving,
you may have to add some ferts, but...wait till the plants
tell you that you need it. Just adding the ferts before
hand may encourage algae growth.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--