A note on CO2 diffusers…
A note on CO2 diffusers…
There seems to be a LOT of different opinions on just what is the “best” way to be getting gas into a tank. Some of these range from the VERY expensive to the ultra cheep; and from the “probably very effective” to a horrible amazing waste of time.
So iv finally gotten around to getting my 90gal up and running, and I decided to try something somewhat different out; and well honestly I don’t think I’m ever going to do anything else!!!
So please forgive the crude drawings and hopefully this works for you too!
So essentially the idea works when you are using a closed circuit canister filter… The gas is to be injected directly into the “dirty” water intake on your tank. In the setup I am using, the gas exits the air tubing an inch below the uplift pipe, so the bubbles are visible for a brief moment before getting sucked into the system. The bubbles are then pulled through the pipes to the pump; where the CO2 is then pulled through the impeller. The atomized gas then is pushed into the bio filter from the bottom (first pic after the diagram.) The OUTLET for the “clean” water going OUT of the biofilter is actually located about 3” lower than the top of the actual filter its self. The biofilter is filled with lava rock, so as the gas rises to the top of the filter it is forced to navigate 80 lbs of rock. WHEN/IF it gets to the top it is resigned to simply pool there until it finishes dissolving, so in essence this is similar to the “diving bell” design; however there is a LOT more surface area (read the total diameter of the filter, which in this case is a good 2’, AND there is moving water underneath; which (in my mind) helps to further facilitate the dissolution… In order for the gas to escape the system; the filter would have to fill up to at least 3” of gas, which does NOT seem to be happening. Further more because the filter is located below the tank AND it is being pushed by a pump; there should be a slightly higher pressure at the bottom of the filter as compared to the top of the tank; which I THINK should also be helping the whole process…
BUT as a note even with a VERY high flow rate of CO2 (faster than I can count) I haven’t seen a SINGLE bubble exiting back into the tank; meaning 100% of the gas is getting into the water!
The pearling off of the plants is incredible and this is a relatively cheap solution compared to some of the fancier atomizers out there…
I also came up with another even simpler solution; however I haven’t tried it yet… Inject the gas the same way as before, but if you don’t have a filter with an airspace, then on the dirty water pipe, while the water is STILL being pulled DOWN by the pump, step up the pipe diameter to as large as you can go. So for example go from a 3/4” line to a 4” line, have the 4” line be approx 1’ tall, and have it mounted in the stand vertically, so water enters at the top, and exits at the bottom.
The idea would be that bubbles get pulled through the pipe, to the 4” line. While the bubbles are in the 3/4” line the water flow rate going down is sufficient to overcome the uplifting force of displacement of the CO2. However, once the bubbles enter the 4” line the flow rate will be greatly reduced, to the point that the bubbles with start to rise in the 4” line, however seeing as there is no place to go they will simply collect there until they have dissolved… This idea may take some fiddling to get the right flow rates and the right pipe size, but id hedge a bet that it would work as described the first time through… If anyone tries this or already had, please let me know how it works!
My Bio Filter
Co2 entering the lift pipe
Lift pipe and clean water return
A note on CO2 diffusers…
There seems to be a LOT of different opinions on just what is the “best” way to be getting gas into a tank. Some of these range from the VERY expensive to the ultra cheep; and from the “probably very effective” to a horrible amazing waste of time.
So iv finally gotten around to getting my 90gal up and running, and I decided to try something somewhat different out; and well honestly I don’t think I’m ever going to do anything else!!!
So please forgive the crude drawings and hopefully this works for you too!
So essentially the idea works when you are using a closed circuit canister filter… The gas is to be injected directly into the “dirty” water intake on your tank. In the setup I am using, the gas exits the air tubing an inch below the uplift pipe, so the bubbles are visible for a brief moment before getting sucked into the system. The bubbles are then pulled through the pipes to the pump; where the CO2 is then pulled through the impeller. The atomized gas then is pushed into the bio filter from the bottom (first pic after the diagram.) The OUTLET for the “clean” water going OUT of the biofilter is actually located about 3” lower than the top of the actual filter its self. The biofilter is filled with lava rock, so as the gas rises to the top of the filter it is forced to navigate 80 lbs of rock. WHEN/IF it gets to the top it is resigned to simply pool there until it finishes dissolving, so in essence this is similar to the “diving bell” design; however there is a LOT more surface area (read the total diameter of the filter, which in this case is a good 2’, AND there is moving water underneath; which (in my mind) helps to further facilitate the dissolution… In order for the gas to escape the system; the filter would have to fill up to at least 3” of gas, which does NOT seem to be happening. Further more because the filter is located below the tank AND it is being pushed by a pump; there should be a slightly higher pressure at the bottom of the filter as compared to the top of the tank; which I THINK should also be helping the whole process…
BUT as a note even with a VERY high flow rate of CO2 (faster than I can count) I haven’t seen a SINGLE bubble exiting back into the tank; meaning 100% of the gas is getting into the water!
The pearling off of the plants is incredible and this is a relatively cheap solution compared to some of the fancier atomizers out there…
I also came up with another even simpler solution; however I haven’t tried it yet… Inject the gas the same way as before, but if you don’t have a filter with an airspace, then on the dirty water pipe, while the water is STILL being pulled DOWN by the pump, step up the pipe diameter to as large as you can go. So for example go from a 3/4” line to a 4” line, have the 4” line be approx 1’ tall, and have it mounted in the stand vertically, so water enters at the top, and exits at the bottom.
The idea would be that bubbles get pulled through the pipe, to the 4” line. While the bubbles are in the 3/4” line the water flow rate going down is sufficient to overcome the uplifting force of displacement of the CO2. However, once the bubbles enter the 4” line the flow rate will be greatly reduced, to the point that the bubbles with start to rise in the 4” line, however seeing as there is no place to go they will simply collect there until they have dissolved… This idea may take some fiddling to get the right flow rates and the right pipe size, but id hedge a bet that it would work as described the first time through… If anyone tries this or already had, please let me know how it works!
My Bio Filter
Co2 entering the lift pipe
Lift pipe and clean water return
