CO2 and algae production

[Fourthwind]

I have had minor issues with PH being steadily low. 7.9 to 8.0. Since my house is on lock down for most of the year, I decided it was time to try a co2 scrubber on one of my tanks protein skimmers. While I was doing this, I had a few thoughts come to mind. Does excess CO2 also affect algae growth in the marine environment? From what I can pull out of study documents, the answer is yes. Just to what degree do we see this in the home aquarium? We all concentrate on food sources like Nitrate and Phosphate, but are we missing something here? Anyone have any personal experience with this? Thoughts?

 

[maxthedog2000]

Hmm, I've never thought of this in the reef/marine setting. I know I have used it for growing plants in FW systems!

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[Fourthwind]

One of the papers I read states that 50% of green house gases in the atmosphere are consumed in the oceans by algae and phytoplankton. one of their experiments showed that phyto's have the ability to grow and consume more if given, but the concern is that with higher phyto growth, that the deadfall going to the bottom was increasing deep water acidity. Little off topic here, but it is "food" for thought.

 

[SynDen]

Freshwater systems use CO2 directly infused into the tank water, to act as a super fertilizer for a planted tank. So yes, CO2 can fuel algae in just about any environment. Its all about balance though. Out in the oceans the carbon/nitrate/phosphate ratio is like 160:16:1, so ya the oceans are absorbing huge amounts of CO2 but the main organisms consuming that carbon is the phyto plankton, which in turn fuels the entire ocean ecosystem.

 

[jda123]

There is enough in any tank. How much more that you need is certainly debatable, but I don't think that you need any more at all. You cannot really do much without lowering your PH. RHF posted years ago to never worry about CO2 in a reef tank, so I have always gone with that. Even with a PH at 8.4 and a lower amount of CO2, you can still grow all of the algae that you want if you let your nutrients get away from you.

 

[Fourthwind]

There is enough in any tank. How much more that you need is certainly debatable, but I don't think that you need any more at all. You cannot really do much without lowering your PH. RHF posted years ago to never worry about CO2 in a reef tank, so I have always gone with that. Even with a PH at 8.4 and a lower amount of CO2, you can still grow all of the algae that you want if you let your nutrients get away from you.

My thought was if there is excess. Not do we add more. Upon further research I have found that both phyto, micro algae, and dinoflagellates have the ability to use ultra low co2 levels with a special cell structure that affectively doubles the co2 they intake. In other words it doesn't look like we could strip enough co2 to slow down algae growth in the home aquarium. Interesting topic however.

 

[jda123]

If you did, then your PH would skyrocket well above what is healthy. This is effectively what adding kalk does - it drives off all of the CO2.

 

[greghl]

If you did, then your PH would skyrocket well above what is healthy. This is effectively what adding kalk does - it drives off all of the CO2.

it does? Hmm... since I laid off the kalk the algae has got much worse in one tank... gonna order more kalk.