Mods and Updates

This post is not a full how-to on DIYCO2 rigs.  There are plenty of forums guides and web pages to tell you how to and why.  If you want the blow by blow on DIYCO2 we invite you to read the Aquatic Plant Central thread with pictures and explanations, not unlike Alice's Restaurant.  We are concerned here with a couple of simple mods and the actual liquid solution we found most efficient to date.

Now that we have our brine shrimp hatchery caps on the DIYCO2 2L bottles, we finally drilled the water intake of the filter and inserted the outflow from our CO2 into the intake.  This modification serves two purposes; first it delivers CO2 to the impeller which then breaks up the bubbles, dissolving them before returning the filtered water to the tank.  Second, the filter intake serves as a bubble counter.  We are able to see the drop off of bubbling and better monitor changing the DIYCO2 solutions.  The more completely dissolved the CO2 is in the water, the more available carbon dioxide there is for plant use.  The only bubbles you want floating to the surface are the micro-fine oxygen bubbles plants exhale.

For those of us who do not want to invest in an injected CO2 rig, this solution works well for a ten gallon aquarium.  Our DIYCO2 rig sports two 2L bottles; one with long lasting jello solution and one with the standard mix.  The bottles were changed out at week and a half intervals.  Now we can monitor the drop off of CO2 in each solution more precisely.  We may get a full two weeks out of each bottle using these two modifications.

These are the solutions we use:

Long Lasting Jello Solution

1 2L soda bottle and a funnel
1 pkg unflavored gelatin
1c sugar
1 tsp yeast


Into 2c hot water dissolve 1c sugarand 1pkg unflavored geletin, pour into a shallow pan, refrigerate until set
Slice jello into strips 1/2" or less wide, turn pan slice again, the smaller the cubes the easier they go through the funnel into the bottle, when the cubes get stuck, use a skewer or knitting needle to force them through the neck of the funnel

Pour 1pkg yeast into 2L bottle, then fill with water to where the curve of the bottle starts, do not overfill.  Cap, insert air hose, shake a gently to help distribute the yeast. You may see the solution begin reacting right away or it may take 1/2hr to 1hr to begin reacting. 

If your solution begins to react vigorously and bubbles into the airline hose you can remove the cap, wait until the reaction slows; some place a check valve on the airline hose to prevent solution from entering the tank and tank water from back washing into the hose.   
Using a longer air line hose and making a service loop will also keep the solution from entering the tank and vice versa.  Some employ an intermediary bottle of plain water to serve the same purpose.  Run the CO2 line from the 2L bottle into a smaller, airtight container of plain water, then run another hose from the smaller container to your tank.
{hose from CO2 must be in the plain water, hose from the water to the aquarium must not be in the plain water}
I find these steps unnecessary; we place our solution above our tanks allowing the downward pressure of the CO2 to do the job of the check valve.

The regular DIYCO2 solution:

2L bottle with airline from cap long enough to enter your tank filter or other diffusion device.
2c hot water, to this add 1c sugar, dissolve
1 tsp yeast

The method is essentially the same; dissolve the sugar in very warm water, let cool to tepid
Pour sugar solution into 2L bottle, add yeast, fill with water to bend in bottle.  Never put yeast into hot water, you will kill it.  Yeast is most active between 86F and 100F.  Do Not Overfill.
Cap and position for use with your aquarium.  This solution will produce CO2 for 2-3 weeks.  You can pour off some of the solution after a week and replace the water plus a teaspoon of sugar, lowering the alcohol content and supplying fresh food for the yeast.  If you do this, add the sugar first, then slowly add the water.  It will fizz up like champagne, so do it in the sink.

Our Jello solution was made five days ago, it is still putting out 3-5 bubbles per second.

One last note about getting the CO2 into the aquarium water; the Hagen AquaClear Aquarium Filter
has a little hole next to where the intake pipe attaches to the filter, your airline hose will fit into this hole if you thread the top of the AquaClear onto the airline hose first.  Do not force the airline hose, it only needs to go in far enough for the friction to hold it in place.  Make sure your filter is primed and running when you insert the hose; if the filter is not running, the impeller will sometimes not start when you turn the filter on.   The opening slot in the top of the AquaClear is just wide enough to accommodate both the knob on the top of the intake and airline hose.  It will be a snug fit.

This method eliminates the need to drill a hole further down the intake tube, as we did in the shot above.  We have one AquaClear filter with the drilled intake above and one with airline hose fed directly into the impeller box.  There is no discernible difference in performance between the two methods.

Feel free to leave comments or ask questions.  Below is a list of video clips showing various methods of rigging your DIYC02.  We have not tried all the rigs, we concentrated on finding the most efficient liquid solution to produce CO2.

Quick Directions:  http://www.youtube.com/watch?v=edoUwvaVy-M
The Full Explanation:  http://www.youtube.com/watch?v=IZFM9ZpaqGM&feature=related part 1 of 2, we love this kid.  He did a really good job teaching.
Pt 2, The Diffuser:  http://www.youtube.com/watch?v=uaVqxwaF8Y0&feature=related  have we said we love this kid?
Alternative Bottle w/Better Seal?  http://www.youtube.com/watch?v=k1LygSE0ByY


As always thanks for reading.  Comments and questions are always welcome.