CO2 dosing in nano reef

[edman]

I am setting up a 30 litre nano reef tank with skimmer. I am thinking of using a CO2 regulated dosing system using ADA tropical pollen glass. I understand that the PH can be driven downwards by dissolved CO2. Will CO2 be driven off through gas exchange from Mame protein skimmer? What chemical reactions will take place? Will carbonate hardness increase? Will bio Calcium levels increase or decrease?

Many thanks in advance, Dave

 

[Randy Holmes-Farley]

I'm sorry, I do not understand what ADA tropical pollen glass is.

What are you trying to accomplish with CO2?

Its only common utility in reef aquaria is to dissolve calcium carbonate in reactors to supply calcium and alkalinity.

 

[brandon429]

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that item is for freshwater planted use I can't think of one single use for it in a nano reef. It performs a vital function of co2 dissolution and it works wonders in the planted tank. used identically in the nano reef I suspect it will kill it all rather fast.

The only known use for c02 supplementation in the nano reef Ive heard of is injection into a calcium reactor, again pretty uncommon in smaller tanks.

 

[Randy Holmes-Farley]

If you are talking purely CO2 addition, that is generally unnecessary in reef aquaria. Most people have excess CO2 already, so their pH is undesirably low.

The only folks who would benefit are limewater (kalkwasser) users who may have pH higher than they like, but aeration usually is the answer for that.

 

[edman]

Oh sorry, I forgot to mention that I'm using limewater to replace evaporated water. I have seen this method used in only 1 LFS in the UK and was stocked with caulerpa, which would use the excess co2 and lock in phosphate and nitrates. I was wondering if the algae contained in zoas, hard corals and clams would benifit from added co2, though I realise this co2 addition would possibly counter act excessive ph additions from limewater, ph 12 ish would the co2 benifit Algae contained in soft and hard coral tissue? What chemical reactions take place? Thanks again, Dave:hmm5:

 

[Randy Holmes-Farley]

Generally, CO2 is far more available in seawater than in fresh due to the organisms using bicarbonate (HCO3-) as their CO2 source. So it is not needed or useful to inject CO2 unless you have pH above 8.5, which is unlikely.

FWIW, I replace all my evaporated water with saturated limewater and my pH is not above normal (8.2 or so).

 

[edman]

With this being only 30 litres, possibly 25 litres allowing for displacement, would I expect much of a ph swing adding limewater to the system, Possibly upto 1/2 litre over 24 hours, then with a ph controller I could add co2 to control ph and avoid big ph swings?

So there would be no other advantages to zoas etc to add co2?

Thanks for you replies. Dave

 

[karsseboom]

Are you sure it wasn't a calcium reactor? Did you see the co2 tank and just think it was used like a planted system. A lot of people use co2 tanks of there reef but it's for a reactor. I can see absolute no value of using it on a reef tank.

 

[bertoni]

Limewater generally won't cause pH problems if it's dripped into the tank. I wouldn't worry about it very much. There's generally no need or value to dosing carbon dioxide into a saltwater tank. Much more common is the need to remove excess carbon dioxide.

 

[Randy Holmes-Farley]

Adding 1.25% of the volume of the tank as saturated limewater all at once will bump pH by something like 0.6 to 0.7 pH, which it too much of a jump. If spread over a 10-24 h period, the rise is much smaller because the tank pulls in CO2 from the air. That is why people drip it or use dosing pumps (or ATO systems).

 

[edman]

Many thanks for the replies.

 

[Randy Holmes-Farley]

:thumbsup:

Happy Reefing.