Refugium Flow

[ErikH]

Karin, I thought the same thing, but I read it's just the opposite. You don't get enough co2 into your water which keeps it too high. Hold on Ill post a link....

[ErikH]

"As discussed above, a reef aquarium's pH rises when its water becomes deficient in carbon dioxide. In practice, this deficiency can be caused in several ways. The diurnal (daily) change in pH in reef aquaria occurs because of the biological processes of photosynthesis and respiration. Photosynthesis is the process whereby organisms convert carbon dioxide and water into carbohydrate and oxygen. The net reaction is:"


http://reefkeeping.com/issues/2005-03/rhf/index.php#6

[ErikH]

essentially you want the offgassing co2 from your macro to stabilize your PH diurnally as well.

[Europhyllia]

That's very weird! On his Causes of LOW pH he mentions high CO2.
And isn't my macro supposed to put out O2 -not CO2?

[ErikH]

During the day co2 offgasses and at night macro uptakes co2. That's why macro doesn't grow as well on a full 24 hour cycle...

[allan]

Okay Erik, now I'm lost.

Because of the reverse cycle most fuges are on for the stabalizing effect of the PH I'm thinking that you are meaning this...

When the Display tank goes nocturnal, the fuge goes diurnal... or when the lights turn off in the DT, the fuge turns on. So while the lights are off in the fuge the macro is doing it's offgassing of CO2? (who'd a thunk it?), and when the fuge lights turn back on (DT is off) the macro begins the photosynthetic part of its day (Diurnal) and puts oxygen back into the system?

The way I always understood Diurnal and Nocturnal is to describe the circadian cycle of particular animals and plants. By that description both the DT (or the majority of it's inhabitants, definitely not all) and the fuge (by this I mean strictly the algae) are diurnal. We off set the fuge light cycle to stabalize the downward swing of the PH during the lights off period of the DT.

This is where I'm a little confused, when you say day, are you referring to your day, your DT's day, or the fuges day?

My head hurts.

[CoryDude]

allan, you me an imatrex for the migraine I'm getting from reading your post.

So after reading this (thanks so much for the discussions so far) I'm thinking about splitting my overflow return to supply the fuge. That would be about 400gph into a 29 gallon tank. I never thought about the extra co2 uptake by the plants. That coud benefit my bacteria filter since co2 is byproduct from it.