High efficiency Ca Reactor mod

Playfair

Premium Member
I installed this idea a couple months ago to 1) Reduce the C02 gas leaving the rxr, and 2) maximize C02 usage efficiency. It has worked well, cutting my gas usage by 1/2, and helping to prevent "vapor lock" from clogging the effluent line. In my case, I drip 200ml/min eff, but the bubbles are only at 30bpm, and rxr pH is still 6.6 (A.R.M.)! If you want a relatively simply DIY, and you have a "top down" recirculating reactor (like the Geo), then this is for you!

In a nutshell, a second, small recirculation loop is created that allows the gas accumulating at the top of the chamber (normally escapes out the effluent line) to get pulled back into the C02 inlet (in front of the circ pump) and get chopped up again by the pump.

Even though the entire reactor is pressurized from the feed line, the pressure at the top of the chamber is still greater than on the intake side of the pump (chamber bottom).

This first pic shows the mods to the rest of the reactor.
secloop.jpg

Another tap is added on the other side of the pump inlet; the 1/8" id tubing fitting that goes here should only be screwed in (or cut) so it is flush with the cover. Both the pump return and the effluent line must protrude below the cover about 3/16-1/4" to make sure the gas goes up the second circ loop. For the existing effluent fitting, I just threaded it ALL the way in. For the pump return, I actually glued a 1/4" piece of PVC pipe over the outlet in order to keep the flow from throughing bubbles around.


This pic show's what has to be added to the lid of the rxr.
rxr_mod.jpg

(1) is a pinch valve, as I wanted to play with the flow in this second loop. It can be left wide open. (2) is the airline tubing that takes the water down to (3) a "Tee" (located below the check valve) which allows the air/water to re-enter the gas line, getting chopped up and forced back into the loop.

Another benefit is that all of the gas coming through the bubble counter is "premixed" with the water in the secondary circulation loop, such that it goes into the pump as small bubbles, then gets chopped even finer. This makes for a constant small gas stream, instead of little "bursts" of C02 getting chopped up.

I hope someone gives this a try, it was 110% worth the time and effort. Lemme know what you think!
 
Playfair,

I am just in the process of installing all my fittings onto a new reactor I made this week. I will try it. Great idea. :thumbsup: :thumbsup:

A concern of mine was the CO2 trapped at the top of the reactor going out of the effluent outlet(as the same thing happens on my smaller current reactor)

Too cool. What timing. :)
 
Cool, DJ88! I've been sitting on this for a while, making sure it worked for a long time before posting. One note... I first tried to use 1/16"id tubing for the 2ndloop, but the pressure difference wasn't enough. Normal 1/8" works great. Make sure you dig up this post from the bowels of the board and post your results!

gas4544, I know, C02 is cheap, but it could run out at the most inconvenient times!
Think of it as not adding excessive greenhouse gasses to the atmosphere! lol
 
This looks like a great idea I think I will try out... I am pretty sure how it should work but this statement confuses me.

Another benefit is that all of the gas coming through the bubble counter is "premixed" with the water in the secondary circulation loop, such that it goes into the pump as small bubbles, then gets chopped even finer. This makes for a constant small gas stream, instead of little "bursts" of C02 getting chopped up.


I don't see why (and it doesn't appear to be set up that way) you would run back through the bubble counter? Am I missing some detail?

Great idea though for sure =)
 
Slug,

It isn't run through the bubble counter. in the photo it looks like it does. The tubing actually T's into the CO2 line after the bubble counter. If you look close you cans ee it. :)

What playfair is saying about;

Another benefit is that all of the gas coming through the bubble counter is "premixed" with the water in the secondary circulation loop, such that it goes into the pump as small bubbles, then gets chopped even finer. This makes for a constant small gas stream, instead of little "bursts" of C02 getting chopped up.

is that the CO2 from the reactor will be taken from the reaction chamber out and mixed with the straight CO2 from the bubble counter output. This mix of CO2 and H2O will then enter the circ pump and be chopped up, some of it again as it may be passing through for a second time.

Does that help?
 
I think you've got it, DJ! Sorry about the wording, Slug, but it's kindof a hard thing to describe... (Maybe I should take an mpeg? lol)

Normally, the C02 under pressure "bubbles" into the intake of the circ pump. The size of these, depending on the injection method, can be substantial enough that the bubbles don't get chopped very fine.

Because the gas is now directly mixed with a moving stream of water, it enters the pump intake already as small bubbles. Thus they are even more finely ground up. Hope that helps a little!
 
Yeah, that's how I thought it worked but something about the wording of that one sentance made me think I was missing something... thanks =)
 
Thanks for sharing. I will incorporate that change into a larger CA reactor I am making for my soon to be 375g tank.........
 
So Playfair, I got to thinking about this mod. I understand that the recirculating pump would suck in excess co2 that was to build up. When there is no excess wouldn't this draw water throught the line thus bypassing the media ? Or does it not have enough umph to pull water through ?
 
Whoa, somehow I missed a couple newer posts...

DJ88- Looks Great!! I see some improvements you made already, like the nice fittings :)

David- Yes, there is always a trickle of water running through the 2nd line, with occassional bubbles when they collect at the top of the chamber and find their way to the outlet. This does by-pass the media chamber, but is a relatively small amount (like 1 or 2 gph) and would has minimal impact on the mail loop.

As the media gets smaller and packs, the pressure difference goes up, and the "trickle rate" increases. I put the pinch valve on the line to maintain just enough flow to push the bubbles through, but it's not required.
 
Playfair,

Due to some unforseen happenings it has taken me a bit to get my Rx running.

Well after much ado. it is running.. :D

I had a few probs getting the recirc line to flow but after a couple of minutes I figured it out. Pretty simple mistake. I tapped the recirc line into the CO2 line in thinking the suction of the intake into the MAG would draw the water from the top of the chamber into itself. Nope. So I added a 1/4" valve on the recirc line just after it leaves the top of the chamber. Seems to be working so far. My fingers are crossed.

I will keep you posted as the pH in my Rx drops and see how much in the way of BPM i am needing.

Thanks for the idea.

Man can I be dumb.. I just noticed that in your last post on this thread you mentioned a pinch valve.. lol.. man o man. gotta get some new glasses.
 
Well after an hour of watching I have to say the recirc line works well. Any CO2 that is collecting at the top is being pulled back into the MAG to be chopped up and sent back into the Rx chamber.

Thanks again. :D :D
 
As I am new to the CA reactors, I have some questions.

What is the use of the bubble counter and at what rate should it flow?

I have made an EV150 and it works pretty good. I figure if I made that then I should be able to make this as well.
 
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