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migdem 09-07-2010 11:25 AM

Calculating how much CO2 I need in my tank
So my tank a 60 litre tank has a PH of 8 and KH of 3. According to the CO2 chart I have 0.9ppm CO2. Now the ideal CO2 concentration for a CO2 enriched tank is anywhere between 15ppm and 30ppm.

How can i calculate co2 in bps to enter my tank to achieve at least 15ppm meaning ph down to 6.8 and kh remains at 3.

CO2 - PH - KH Chart

redchigh 09-08-2010 09:20 AM

Those charts aren't as accurate as everyone seems to believe...

Do you really want to supplement CO2?
If you really want to, then I can't help a lot...I would just add CO2 until the Ph drops to 7.4-7.5 or so...

I just wanted to stop in and say CO2 supplementation isn't mandatory. If you have fish, you will have excess co2 for the plants.

migdem 09-08-2010 10:42 AM

then why do alot of people state that co2 for plants are important to give through a pressurized system?

Byron 09-08-2010 12:13 PM

I wrote on this not long ago, but as I can't find it, I'll try to summarize.

Aquatic plants will live in almost any environment (here meaning substrate, light, water parameters). But growth (i.e., photosynthesis) will vary greatly. I have fish aquaria that include plants, so my approach is different from an aquarist who wants a plant tank without fish, or with few fish. Each of us will approach things differently because we are after a different goal.

As I frequently mention, plants will only photosynthesize if there is a balance of light and nutrients sufficient for their individual needs. One macro-nutrient needed by all plants is carbon, usually assimilated via CO2 though some plants are well able to assimilate it via bicarbonates. But carbon is necessary for photosynthesis to occur. Different plants have different needs respecting light and nutrients. But no matter what, these must be balanced for the specific plant.

Once the balance is achieved, then comes the level. Plants will "live" at a low level if it is balanced. I had a 33g running for several months with no fish, just "spare" plants. The light was on normally (all tanks are on the same timer) and I dosed Flourish once a week. There were no fish in that tank. The plants did well, better than I would have expected. Obviously their need for carbon came from somewhere, presumably the bacteria and Malaysian livebearing snails, and from the air at the surface (esp the floating plants). The plants in this tank were not as robust as those in my main tanks--which is to say they did not grow as fast or send out runners as much--but they were green and alive.

The level at which each of us wants the plants to grow will determine what we have to provide. Or in reverse, the plants will respond with growth that is dependent upon what we provide, by which I mean light (intensity and duration) and nutrients. Some plants demand higher levels of these, but many will exhibit various levels of growth in relation to the level of light/nutrients we provide.

To say that plants cannot grow in an aquarium without added CO2 is simply false; not that you're saying this, but I know there are some "authorities" who do give that impression. There are a few plants will not do well, and some others may have very slow growth--though increasing CO2 itself will not help if the light and other nutrients are not increased to balance. But the majority will manage fine with the carbon available via CO2 from the fish and bacteria--and there is considerably more CO2 from bacteria than from fish.

To end with an example: the extremely high-tech setups of Takashi Amano that were discussed in another thread earlier this week require mega-light (4-5 times the intensity I have), CO2 diffusion, and daily injection of copious amounts of fertilizers to provide the nutrients to balance. These tanks are very high maintenance, and very expensive to setup and operate. And there is a considerable amount of intervention by the aquarist (via equipment and maintenance) in the normal natural processes that result in a healthy aquarium. By contrast, I do nothing more than a weekly partial water change and dose a minimal amount of liquid fertilizer twice a week. The plants I select do well in this minimal approach. Each aquarist has to decide the level in plant growth that he or she wants and then be prepared to provide what is essential to achieve that level and keep it stable.


migdem 09-08-2010 12:28 PM

I see, well i bought the things for a high tech but not so high.

So my aqaurium is 450 litre tank with 216W T5 and will install reflectors so I will have medium/high light for 10 hours a day on a timer. Soon I will send the photos since I ordered the plants and waiting for them to arrive and plant them. I have a PH controller with CO2 Pressurized system. This is set to 6.8PH and have 3KH. My current ph with no co2 added is 7PH so i will add little co2 to the system. I will be doing biweekly water change of 25% of tank around 110 litres. I cannot do more and often than this since I do not have so many time and also have other aquariums to take care.

Now for ferts I compared some prices with Flourish and PMDD and resulted in PMDD is much much much cheaper so I have to go for this. I found this website James' Planted Tank - PMDD and thought I could try it out. Do you think I could dose the ferts once or twice weekly since I am a bit pressed on time? Do you think that the PMDD is sufficient for my aquarium?

redchigh 09-08-2010 01:03 PM

PMDD is interesting...

Wow, 100 gallon tank? I'm jealous.

I wouldn't do PMDD... Just seems dangerous.

Of course, that is a pretty big tank...

I don't think it's worth risking your livestock, plants, and health (some of the ingediants can cause chemical burns) to save a couple bucks...

Flourish goes a long way, and has everything pre-mixed.

Dosing PMDD seems a bit confusing... I looked around and found this-

Consensus is to dose PMDD so that you accumulate and maintain around 0.1mG/ltr (0.1 milli-grams/liter or 0.1 Parts Per Million) concentration of Fe (Iron) in the aquarium. Exceeding 0.2mG/ltr of Fe seems to be counterproductive.

migdem 09-08-2010 01:39 PM

there are so many people that use this method I do not think that anything has gone wrong since no one posted wrong things about this method.

redchigh 09-08-2010 01:46 PM

To each his own. :)

Let us know how it goes.

Byron 09-08-2010 06:32 PM

I have always been leery of dosing ad hoc nutrients. This individual seems to have made up the formula though, so it may be OK. With respect to cost, though, are you sure it's cheaper? He is suggesting 3 times the amount of each Flourish dose [Flourish is 2.5 ml per 30g, James says 2 ml per 10g, so 6 ml for 30g is almost 3 times]. Bear that in mind when assessing cost.

And I still think twice weekly fertilization will be insufficient to balance your light and CO2. Our tanks are both 115g, you have 216w of T5 light compared to my 80w of T8 full spectrum which is almost triple the intensity assuming you have T5 NO, if it is HO then it is close to 5 times. I have the lights on 11 hours daily, and I have no CO2 diffusion; yet it takes twice a week doses of Flourish to keep my swords green. To maintain a useful balance you will need daily fertilization, or will have to reduce that light. While your plants may do well, the additional light and CO2 will not help them without the other, but will encourage algae. And reducing the duration is not the answer.

I don't intend to sound negative; it is just that I would like to see others succeed with planted tanks, whatever the method they may use.


migdem 09-09-2010 02:25 AM

Ok will try it out at first since I already buy the equipment. I will give you results within one month.

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