CO2 Injection vs Plant Growth Rate

[GraemeK]

Hi All,

Both my tanks have what would be classed as low light which i cannot change unless the built in hood was taken off. Something i dont plan to do just yet.
I also added Pressurised CO2 to my main tank in the past however i found that due to my lack of light and choice of plants (java ferns, Crypts, vallis and hygro) nothing really changed other than the Hygro bolted towards the surface at what appeared to be a weaker appearance. Hence i removed the Co2 and made suttle changes to adding my Tropica Nutrition plus ferts and now have steady growth, if not a tad weak in appearance.

My question to everyone:

I know Co2 is required in high light situations to keep that balance but am i right in saying that CO2 on low light tanks is a waste of time for the reasons i discovered? Or are there beneifits to adding Co2 regardless of plant choice and light levels?

Reading on a retail website it suggests that even liquid carbon such as Flourish Excel do have benefits to the plants growth, do all low light (low tech) tanks still use Co2 or is this simply choice depending on the growth rate required?

I would love my crypts and hair grass to fill out quickly but adding too much ferts causes algae and adding Co2 only appears to cause some plants to bolt.

does liquid carbon affect shrimps?

thanks for all that read this.

Graeme

[bradac56]

Your plants will use and produce C02 naturally in low light just not as much as with high light and injection. I dose Excel on my low light tanks per Seachem's instructions (1ml per 10gal per day) but that won't give you explosive growth just healthy plants.

I've dosed Excel in shrimp tanks without problems just don't overdose.

[Wasserpest]

TDI tuning... love it. Soot soot.

I know Co2 is required in high light situations to keep that balance but am i right in saying that CO2 on low light tanks is a waste of time for the reasons i discovered? Or are there beneifits to adding Co2 regardless of plant choice and light levels?

I would agree with the second part... While it isn't totally required, adding CO2 in low light tanks will be beneficial to plant growth. Overall, with low light the biomass accumulation is slower. But adding CO2 will lead to nicer, greener, lusher plants anyway.

I'd say it is never a waste of time to add CO2 even on low tech tanks.

[hbosman]

The co2 might even help the plants better utilize the light that is available. Since the plants are having to spend less energy obtaining co2, they can spend it taking advantage of the light that is available. Of course you still have make sure you are balancing this with micro as well as macro nutrients. Depending on fish load you might still need a small amount of KN03 and KH2P04.

[Hoppy]

Algae in aquariums does not result from adding nutrients. People who use the EI method of fertilizing have not experienced big algae attacks from their use of more nutrients than the plants require. The causes of algae are complicated, but just doubling the amount of nutrients you dose will not cause algae to start up.

[bradac56]

I agree with hoppy overdosing ferts (EI for example) doesn't lead to rampant algae growth usually it's a combination of to much light, not enough light, to much C02, not enough C02 that's the bigger culprit, but it gets complicated from there.

- Brad

[plantbrain]

A good article relating to your question is well addressed on Tropica's web site, see CO2 and biology of aquatic plants(Claus, Ole and Troels).

Read their conclusion also.

hbosman is right on track.

Your plants are much better able to use the light much more efficently, since they will allocate more of the resources to gather light, not CO2.

So you have much higher light use efficiency with CO2 enrichment.
In lab studies, they get 10-20x more growth using the same light and CO2 enrichment.

That's huge.

Excel is not a bad in btw method either.

You have to look at plant growth holistically however.
It's not just about dosing ferts, or dosing CO2.........or light, it's all of them together.

If you add more CO2, then expect more growth, more nutrient demand,m higher light use efficacy.

More light= more CO2 demand= more nutrient demand
Less light= less CO2 demand= less nutrient demand.

and so on........

For nutrients, enriched sediments make remembering to add liquid ferts easier and provide a redundant back up. Likewise, adding liquid ferts allows the sediment to last longer and less transport of nutrients for the plants/less risk of deficiencies specific to the sediment alone.

So a mix of both works nicely.
If you have a decent fish load, then often they can provide a good % or at leats back up supply should you forget, or if you wanna dose NH4(better to have the fish do this than monkeying with urea or NH4Cl etc).

Read the article on Tropica's web site, I think it will answer things well for you.

Regards,
Tom Barr

[GraemeK]

Thanks to all that replied to my thread, this makes more sense now and upon reading the Tropica study i am about to rig up my CO2 system again but keep the levels modest. I'm keen to see what happens and will make sure that my ferts are spread out throughout the week rather than dosing all at once which probbaly isnt sufficient for the plants demands throughout the week. I have some plants like Dwarf chain-swords and crypt parva but neither have romped away on the foreground to create a carpet like affect. so i'm hoping that a little added CO2 combined with regular ferts will help. to combat the lower than ideal light levels at that depth.

thanks!

Graeme

[MarkMc]

At what point does excessive ferts cause any detrimental effect? If you follow the advice of people in the know it would seem that the main culprit in poor growth or algae problems is the lack of proper CO2 into the system. BTW I'm becoming a believer in that advice. So my question is: Is it really necessary to do a weekly 50% WC? What about a 10% to 20% with diligence towards filter maintenance and vacuuming of organics on the substrate? What do you all think?

[JDowns]

Originally Posted by GraemeK

Thanks to all that replied to my thread, this makes more sense now and upon reading the Tropica study i am about to rig up my CO2 system again but keep the levels modest. I'm keen to see what happens and will make sure that my ferts are spread out throughout the week rather than dosing all at once which probbaly isnt sufficient for the plants demands throughout the week. I have some plants like Dwarf chain-swords and crypt parva but neither have romped away on the foreground to create a carpet like affect. so i'm hoping that a little added CO2 combined with regular ferts will help. to combat the lower than ideal light levels at that depth.

thanks!

Graeme

Also take into account that plants will need time to adjust to the added CO2 levels. This energy transfer is not immediate.