C02 rx questions.......

Chin_Lee · #1 08-22-2005, 05:54 PM

I'm in the setting up my calcium reactor stage and I've got my efluent cranked up to about 275ml/min (just over a cup) right now because my reactor cannot maintain the alk level in my tank.
My reactor is the dj88 design and currently holds two full big jars of media, effluent is 7.0 ph, my bpm is at 90. My ph has dropped from daytime 8.2 to 7.9. I also have a beckett skimmer that sucks in air like mad and i'm hoping to minimize the lowered ph effect.
So my first question is:
If I were to place the c02 effluent in pre-skimmer water, when that water goes through the skimmer, will it assist with removal of dissolved c02 therefore minimize the ph drop associated with calcium reactors or will it just screw my my beckett skimmer's ability to foam?

I plan to add another jar of media to increase the capacity of my reactor which I suspect I will need to increase the bpm slightly. So my second question is:
How else can i get the most out of my reactor?

edited because I hate spelling errors

danny zubot · #2 08-22-2005, 06:01 PM

Chin, my skimmer, which was your skimmer, doesn't foam as much at night when the PH drops. I used t think it was because metabolism in the tank has slowed down. And until you brought this up I didn't really think PH had much effect on foam fractioning, rather salinity etc.
The PH drop I experience at night is usually 0.2 at the most.

StirCrazy · #3 08-22-2005, 11:18 PM

Chin Lee, what is the alk of your reactor output? forwhat its worth 7.9PH is ok (it is what I have had for the last 3 years.)

Steve

Chin_Lee · #4 08-22-2005, 11:57 PM

Steve
Hmmm haven't really checked but I will test it and post when I get home tonight.
My concern is not really the ph of 7.9 but the possibilty of it getting even lower is whats not making me comfortable.

reeferaddict · #5 08-23-2005, 01:48 AM

Chin,

How big a tank are we talking here? Your effluent and bubble rates sound really high... try dropping BOTH the C02 and effluent rate DOWN by a factor of ten... then test the effluent for Alk & Calcium ... then what you need to do is calculate how much effluent at say 800pm Ca and 20 DKH Alk it's going to take to keep up with demand. To establish demand is simple, test for Ca and Alk 24 hours apart with absolutely no supplementation during the 24 hour period... Another solution to high C02 thus low PH may also be to run the effluent into a brightly lit refugium with some macro .... your algae would grow like wildfire and consume C02 AND nutrients all at the same time... run the refuge on a reverse light cycle and that will help too... I have Caulerpa in my fuge that's doing fine under PC's right now... but I'm going to upgrade to a 250W MH just to get more photosynthesis happening thus a further reduction in C02 ... I'll let you know how that works out... curious to know how your nuisance algae growth is when your reactor is running... Steve's right about the low PH being OK... lots of people keep their animals in that range... the real factor is the presence of Alk... BUT... from most of the reading I have done, I also understand that calcification as well as carbonate uptake happen much more efficiently at a higher PH, so while a low PH can be OK... better growth rates have been observed at PH's above 8. BTW... natural sea water has a PH of 8.2... period... any place you can collect a couple miles off shore where pollutants aren't a factor, you're going to get 8.2... the exception would be in those highly photosynthetic regions where it might push to 8.3... What is your corraline growth like? If it's slow then you probably have phosphates present, (which virtually ALL reactor media leeches into the water column), which probably won't register on any test kit, as they will bind quickly in the system, being undetectable, BUT there. I have actually gone back to a variety of supplements, as I find them easier to be precise with, and when I get a phosban reactor and get the phosphates out by removing any algae in the tank, I will be dripping kalk at night, and the reactor during the day, but I'm going to regulate my C02 into the reactor with a PH controller. That coupled with my reverse photosysnthesis will hopefull keep my PH at a constant 8.3... right now I have a high of 8.35 and a low of 8.15... still too much of a swing in a 12 hour period IMO...

reeferaddict · #6 08-23-2005, 01:52 AM

This article is good... but I'll post another one that actually explains the chemistry later on...

http://www.reefkeeping.com/issues/20...ture/index.php

StirCrazy · #7 08-23-2005, 12:49 PM

Quote:

Originally Posted by chin_lee

Steve
Hmmm haven't really checked but I will test it and post when I get home tonight.
My concern is not really the ph of 7.9 but the possibilty of it getting even lower is whats not making me comfortable.

ok what you should do is shoot for an alk of about twice that of what you want the tank, it may be as simple as dropping down your flow out of the Ca reactor.

Steve

SuperFudge · #8 08-23-2005, 02:44 PM

A Reactor will produce a higher alk at a higher co2 bubble count, rather than a higher effluent rate.

A reactor is also not the best way to raise Alk, it is better at maintaining alk and raising calcium.
Depending on how low your alk is and how high your Ca is, It might be better to raise it with an alk buffer, then dial it in to maintain it.

I wouldnt worry at all about the effects of ph dropping at all, you would almost have to try, to really drop ph.
As your alk raises, it also is helping to prevent a drop in ph.

If you just keep the effluent line above the water level to let exess co2 burp out into the air, youll be just fine.

props · #9 08-23-2005, 06:08 PM

hey chin
you should sell me your ph monitor so you don't have to worry about it...

or lend it to me for a day as i haven't checked my ph in two years.