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Plan>B
11/14/2009, 06:47 PM
I am looking to adding a CA reactor, and was wondering why do some (think DIY) CA reactors have more then 1 chamber? How many could you have, is 2 the max or could you up higher?

Would love to have this explained in detail or if there is an article that I could read.

Oh... and how do you size your reactor? How much media per gallon is needed?

jjstecchino
11/14/2009, 07:12 PM
I am looking to adding a CA reactor, and was wondering why do some (think DIY) CA reactors have more then 1 chamber? How many could you have, is 2 the max or could you up higher?

Would love to have this explained in detail or if there is an article that I could read.

Oh... and how do you size your reactor? How much media per gallon is needed?

The first chamber is the main reaction chamber. The second chamber take the effluent with low ph and raises the effluent ph before the effluent reaches the tank. Still some enrichment of the effluent with calcium carbonate happens in the second chamber but to a much less extent then the main chamber. Why would you have a second chamber? Mainly to avoid lowering the tank ph too much, expecially if you need the reactor to make a lot of ca and carbonate.

How do you size the reactor? I would follow the manufacture reccommendation and go a tad more. i.e. if you have 150 gal go with a reactor rated for 200 gal.

As far as the media, you need to fill the chamber almost full so it depends on the chambers volume.

If you are looking at setting up a reactor there is a very good article on this month issue of ReefKeeping.

I personally like reactors that recirculate the water from the bottom up. They clog much less then the one recirculating from the top down

rkelley_10
11/15/2009, 12:21 AM
+1

The pH in the reactor's first chamber should be about 6.6-6.8 to break down the aragonite media and release these ions into solution. CO2 lowers the pH by reacting with water in equilibrium to produce carbonic acid in small amounts. Depending on your demand, the CO2 bubble or feed rate into the reactor, and the effluent drip rate, some believe this can noticably lower the pH in your tank. The second chamber allows for even more CO2 dissolution effectively raising effluent pH. If only one reaction chamber is present, some circumvent introducing the low pH effluent by buffering in one of two ways: (1) You can drip the effluent into a small cup or container that overflows into the tank (2) You can drip the effluent in your skimmer or near the skimmer intake. The overflow drip is known to cause a decrease in effluent alkalinity. Is the 2nd reaction chamber a necessity? Not necessarily. Is it a good thing to have? Most definitely if you are concerned about pH fluctuations.

Plan>B
11/15/2009, 01:28 AM
Thanks for all of the replies. So would a third chamber be of any help?

Now I about CA Reactor sizing... I know they sell reactors for tanks, but what if they don't have the size and I want to build/have built a reactor to the size of my tank. Is there any formula for this?

rkelley_10
11/15/2009, 02:36 AM
A third chamber would be of marginal utility and pointless IMO. You can find a lot of DIY plans. Having one built would be quite expensive. As far as a formula, well.....the formula's go into CO2 bubbling rate, effluent drip rate, and desired dKH. Try checking out commercial Ca reactors to view their tank ratings and respective dimensions to get a feel for what you require.

Randy Holmes-Farley
11/15/2009, 09:09 AM
The very short summary of a second reactor chamber is you get better use of the CO2 added, so since you add less CO2 per unit of calcium and alkalinity, you have a smaller pH reduction in the tank.

The effect, however, is not as dramatic as many people think, and not as big as the pH rise in the effluent might suggest. It is not the pH in the effluent that matters, but the total CO2 delivered to the tank. That is the only important effect. All reactors no matter how many chambers will necessarily help drive down the tank pH.

That said, the effect is useful and I'd prefer to have a second chamber. :)

This has more on the processes in a reactor, but not necessarily the second chamber:

A Guide to Using Calcium Reactors
http://www.reefkeeping.com/issues/2002-05/sh/feature/index.php

Randy Holmes-Farley
11/15/2009, 09:11 AM
The overflow drip is known to cause a decrease in effluent alkalinity.

Unless you have precipitation of calcium carbonate at that site, the alkalinity does not drop. :)