I thought about effective CO2 blending for a long time. I've tried almost everything: Diffuser made air from wood, stone, glass diffuser, I've tested CO2 injected canister filter enema, etc.
First is ok, but you have to replace wooden airstone every ~ 2-3 months. Second and third solutions are not effective at all. The last method is ok, but some of the still bubbling through the filter and wasted, gas bubbles, did not come off the inside of the filter flow, trough outlet pipe and gone, anyway, at least not elegant way.
I decided to filter my own mixer out of the 5 gallon fish tank, making enclosures.
Basically it's not my idea, and many similar solutions can be found on the internet, but I'll try to describe how I'm made.
Step 1: overview and overview
Mixer is located behind the canister filter, so water comes trough filter as water utilize the CO2 bubbles during flow trough t plug on mixer inlet.
The mixer consists of inline water filter housing. Inside there are handfuls of Bioballs to make CO2 diffusion more effective.
The hardest part of the job I found was filtering proper connectors to connect ordinary filter tubing to mixer and connecting CO2 to find the inlet.
After almost an hour of digging in B&Q plumbing department, I found plastic fittings for standard 15mm water pipes. When I removed nut from one end, I found the same 3/4 inch thread. Fortunately, even better in terms of assembly / sealing, after the thread was a collar, so I could use rubber washer instead of sealing from normal Teflon tape or silicone sealant (you can see everything in the photos).
Step 2: materials
Ok so all you need is:
-Water filter 10 inch housing (in this example I bought one from Ebay (it was very cheap price) but is standard case part link and anyway it could be one of the housings that are available on the market.
-a straight trough plug 15mm tube,
- one equal to 15mm tee connector
-15mm pipe (unfortunately I had to buy 2 m long pipe),
- Hose clips
You will also need silicone sealant, a saw (for cutting pipes), small diameter pipe for CO2 inlet, a handful of bioballs (idea: I got mine from the filter, and replace with pieces of foam or replace completely medium foam /) bioballs complete with foam / ceramic / ** etc. (alternatively you have to use bioballs at all)
Step 3: assembly # 1
The rest of this job is assembly and is pretty straight forward.
5 pieces of tube 4 pieces about 5 cm long and about 20 cm. Fit two 5cm pieces in t-connector and straight connector and pull the caps off. Then you have to connect approx. 2 cm long line to the filter hose. Remaining short piece of pipe that you will use to make CO2 enema.
You have to find straight small diameter pipe about 7 inches long. (A very good source is an ordinary soap doser). Next you need to seal small pipe inside 15mm diameter to 5cm long piece of pipe. There are many ways to do this. You can use Gluegun and silicone sealant to be sure there is no leakage then; or fill the 15mmm pipe with silicone then block the little pipe at the end and put it trough silicone (this is difficult, but possible). Now wait for the sealant to dry out.
Step 4: assembly # 2
All together now.
Screw both plugs into the upper area of the water filter. Tee in connection and straight plug out. Attach both by Teflon tape / silicone sealant / scrubber, it doesn't matter which way you prefer, unless that doesn't leak. I have specified rubber washers (8) for this, and two of them fit exactly, with connectors. When you still need to fit 20 cm pipe in the lid. The drain from be in the housing.
Put the bioballs (or not, it's up to you) in the bottom of the case and screw the lid together.
Now is the time to make a decision is the best place to cut filter exit tube in half.
You have to make another small piece (approx. 8 cm) of discharge tube (of course, the tube must be transparent so that air bubbles can be seen).
When the silicone dries out, you can fit CO2 inlet in 8 cm piece of hose and narrow hose clamp on it. From the other side of the "bubble counter" take the tee connector (just like a small piece of pipe inlet and outlet) and attach the nut (see picture).
When you've decided where and cut the hose in two, its time to put the hose clips on the hose, connect hose to mixer inlet / outlet lines and attach the clips. Note: If its hard to pull on the hose on a pipe. Tip: hot water
use to soften the hose and and become easier.
Connect the CO2 hose to the inlet and make sure that everything is tight (secure the CO2 hose with small cable ties or wire).
If you can safely turn on the filter and see how the new mixer slowly fills with water. When the water reaches the bottom of the inside drain pipe the mixer will likely stop filling, so at this point you have to press the pressure release button until mixer fill with water.
Check for the leak and that's it.
Step 5: heating
Ideas for a future.
This mixer is actually quite neat for the placement of the heater. Main reason for its only aesthetic nature. Basically you don't have heating tank. Second reason is that the heat in the tank spreads evenly (depends on the inlet method of course). On the other hand, it could be dangerous at times. If, for some reason, a large amount of air is flowing in the mixer and level is reached, the heater (or part of the heater) is exposed to air, the heater could crack. To avoid possible electric shock, connect the heater to the RCD switch. Even so, I strongly recommend removing them all before digging inside the tank.
Tip: You can buy heater with water level sound alarm.
Step 6: completion
It is probably one of the most effective ways to dissolve CO2 in water. Also includes the most accurate method for dissolving CO2. I've been using it for 2 weeks (~ 1 bladder / sec) with no problems so far.
You may like to see a happy fish plant in the background.
(Sorry for linguistic errors, there are probably many)
Cheers