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Inline External Reactor not full of water

Discussion in 'CO2 Enrichment' started by gucci17, Feb 16, 2008.

  1. gucci17

    gucci17 Junior Poster

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    I used to have the reactor rigged inline with my eheim filter but I wasn't satisfied with my low flow rate. So I just decided to rig it separately to a powerhead to increase flow in my tank.

    The question I have is, does anyone know if co2 will degass properly if the water level inside the reactor is lower than the co2 injection line?

    I'll try to be more clear. My co2 line is fed through a drilled hole on the body of the pvc (approx. 6" from the top). It's the typical design from Rex Grigg's site.

    I opened it up today (opaque pvc) and saw that the water level is sever inches lower than the co2 line.

    I'm worried that my co2 isn't mixing with my water. Should I add some media inside my reactor to bring the water level up? Is there any other way to bring the water level higher?

    I just changed the regent in my drop checker with distilled water and I'll check in a few hours to see if it changes colour.

    Any insight will be appreciated.
     
  2. tedr108

    tedr108 Lifetime Charter Member
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    A picture would sure help, but...

    There is something wrong and I doubt your CO2 is going to mix properly with the water.

    You need to make a way to bleed off the extra air. On my reactor, I drilled a hole and glue a small piece of rigid tubing into it, to which I attached a small piece of clear flexible tubing with a valve on the end (a simple stopper will do, but hard to get on and off). When my reactor has been drained for any reason, I open up the extra bleeder valve until the water comes up and shoots out of it. At that point, you can close it up and your reactor will stay filled with water until you change water or otherwise drain it.

    You might also want to put a venturi loop in your reactor back to the pump. Tom Barr designed a very nice DIY external reactor (the one I used) and there is a good thread here in this Forum that explains how to make it. I especially like the way his input for the CO2 is designed compared with yours.
    http://www.barrreport.com/articles/3444-dual-venturi-diy-external-co2-reactor.html

    With minor modifications to the impeller, you can also feed the CO2 directly into your powerhead and avoid a reactor altogether.
    http://www.barrreport.com/co2-aquatic-plant-fertilization/3886-another-method-co2-diffusion-needle-wheel-powerheads.html
     
  3. gucci17

    gucci17 Junior Poster

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    tedr108 > thanks for your response. I'm going to try to drill a hole and like you said install a valve to release the air. Hopefully it will fill up.

    I do remember the Tom's DIY reactor. I had wanted to make it but I figured there's no point to scrap the old one since it's been working until now.

    I will keep my existing reactor for the time being and make Tom's as my next reactor.

    Thanks for your help ted!
     
  4. tedr108

    tedr108 Lifetime Charter Member
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    A couple of things more...

    1) Media in your reactor shouldn't really be necessary.

    2) You do not want distilled water in your drop checker, you want 4dKH water. How to make it is explained here in the original post: http://www.barrreport.com/articles/2661-drop-checkers-co2-indicators-why-how.html

    Here is the gist of making 4dKH water in the post... 2 methods:

    -- Add 6 grams of bicarbonate of soda to one liter of distilled water. This gives you one liter of water with a KH of 200 dKH. Now take 10 ml of that water and mix with 490 ml of distilled water (a dilution of 1 in 50) and you get 500 ml of 4 dKH water.

    -- We don’t all have a gram scale capable of measuring 6 grams accurately. Most of us do have a KH test kit. So, it is also possible to arrive at 4 dKH water by mixing a very small amount of sodium bicarbonate into distilled water and repeatedly diluting it with more distilled water until the test kit says we have 4 dKH. Relying upon test kits isn’t a good idea, but in this case it is a good enough idea if we just want to monitor the ppm of CO2 in the water.
     
  5. VaughnH

    VaughnH Lifetime Charter Member
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    The problem with trying to add 6 grams of sodium bicarbonate is that the amount of bicarbonates that gives you depends on how much water has been absorbed by the sodium bicarbonate. And, you can't easily dry out the sodium bicarbonate without also converting part of it to sodium carbonate, which has a different ratio of carbonate to sodium than does sodium bicarbonate. A better method is the second one you mentioned. Since the indicated ppm of CO2 is directly proportional to the KH, any error in KH is the same error in ppm of CO2. But, a similar error in pH makes a huge error in ppm of CO2, because the ppm is inversely proportional to 10 raised to the pH power. This is why the drop checker, when green, only tells you that the ppm of CO2 is from about 25 to 40 ppm, and even that accuracy is possible only if you can discriminate shades of green accurately.
     
  6. tedr108

    tedr108 Lifetime Charter Member
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    Hoppy, I double checked my 4dKH solution against my test kit and it was fairly close (So. Cal. is basically a big desert, so not much water was absorbed, I guess). I also used a very accurate scale for the 6g of sodium bicarbonate when I made the solution.

    Anyway, I came out at 5 dKH with my test kit ... added a little distilled water and came up with 4dKH on the next test. I would think that, if anything, you would end up with less than 4dKH if any water was absorbed inte sodium bicarbonate, so this was a little confusing to me. Anyway, I'm close...
     
  7. VaughnH

    VaughnH Lifetime Charter Member
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    Close is good enough for this kind of test. If you think you have 4 dKH water, and really have 3.5 or 4.5 dKH, your test would mean you only know your CO2 concentration is about 20 to 45 ppm instead of 25 to 40 ppm.
     
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