DIY External Inline Co2 Diffuser

I Like It !

definitely closer to the pump though. That allows for higher static pressure, and greater contact time, and saturation. A dedicated pump would help. The Mazzei injectors are about the best in production.

Update: I just noticed, Do you have the venturi, and ball valve transposed in that configuration ? Shouldn't flow control be on the main line to direct pressure to the Venturi valve ? Never mind me I'm just curious by nature ! ;^)

 

In your 1st. photo...

On your original configuration try swaping out the Ball valve and Venturi. Also reverse the two sections of hose on the bye pass end for end. Short section+Venturi+long section. Then re-adjust the ball valve till you begin to draw gas. Again, placing the whole bye pass assb. closer to the pump may improve line pressure. If you're not seeing enough bubbles entering the tank place the assb. next to the lilly pipe. Depends on whether you want disolved Co2 or micro bubbles. HTH. Prof M

P.S. which model Mazzei Venturi are you using ?

 

Won't the return flow from the booster pump act as a big resistance to the filter flow trying to get by the blast from the venturi output? I would expect to see the filter flow drop close to zero and the booster pump primarily recirculate the same water over and over. If you used an elbow similar to a "sanitary elbow", with the side passage entering almost parallel to the main flow it would work much, much better. The venturi line flow would actually boost the filter flow then.

 

Yup !

That it will ! I'd also increase the output to a corresponding larger size. If I were using a secondary pump I'd just run it dedicated. That venturi valve will only handle a few hundred gph.

 

That's about the size of it, Tom

"I think the issue here is really the size of the tank"

The biggest challenge is properly sizing the volume, and metering the Co2 to accommodate the application.

 

Does he need a pump ?

I honestly believe that if the bye pass is properly configured his present canister is more than sufficient, albeit a bit large for the tank.

 

"sanitary elbow"

RE: "sanitary elbow" You make a significant point. I'll try a radiused turn from the venturi, and a sanitary elbow to merge the line. Can't hurt ? I'll note any difference in flow, and mist.

I'm testing a 1/2" at a dedicated 187 gph. I'll run it straight, and then attach the bye pass. One thing I figured out today was my old Eheim 2217 Classic pushes twice the head pressure of the 2224. Of course the 2224 draws 8W and the 2217 pulls 20W. Apparently that efficiency comes at a cost ?

 

New photo

Alright ! I'm actually jealous...Doesn't happen very often. I don't have the space these days for any more large tanks. Prof M

 

Low Flow Venturis

Seems like common sense now, but VaughnH's observation of of the T inlets is actually pretty significant. Given the restriction of flow all those 90* turns add up quick ! The bye pass is text book, but I don't think that book covers power heads, and mag drive pumps ?

I did recently discover that Mazzei already offers a selection of precision machined stainless steel drop in ports for gas injection venturis. This is good !

Of course I also discovered that the 2100, and 2700 needle wheels are on back order, and the smaller Ocean Runner Pumps are hard to come by. This is Bad !

Then I discovered that the needle wheel pumps for the Super Skimmers can't supply an adeqaute line pressure for remote placement. This is VERY Bad since Coralife appears to be the only source of needle wheel pumps that has even the slightest chance of hitting their @$$ with two hands and a catchers mitt !!!

Difficult to spec a product that can't be supplied ??? The Ocean Runner pumps are good, but if any one knows of any way short of dynamite to motivate their salesmen, Please by all means do fill me in on it ???

The Kent Venturis arent bad. They're not quite as nice as the Mazzei, but they're a good value, and Kent's VERY Reliable. I'm finding out that Reliable counts for alot more than any feature at this point.

 

An inexpensive venturi with a microscopic size orifice for CO2 at the throat sounds like it would work great - for a short time. Then the orifice would plug up. But an inexpensive venturi with a CO2 port having a very small limewood, for example, difuser in the end might work for a substantial time. On one of the forums a poster was promoting the idea of using short pieces of chop sticks - bamboo, I assume. That might work well too. The goal should be, in my opinion, to have multiple microscopic orifices, so until the last one plugs up you still have CO2 mist being generated. I can't see myself doing this experimenting, but I hope someone does.

And, it won't be at 10 bubbles per second, with such small bubbles, but more like 100 per second. That suggests that it would take multiple parallel orifices to allow that much flow.

 

Gas Intake

Sourcing the Venturis, Pumps, and impellers is only a consideration of convenience. Won't do much good to supply a simple process, if the parts themselves are exotic.

I'm focusing on the gas intake for now. As far as constriction goes you can actually go from a 5/8" barb to a 3/4" npt venturi and still supply adequate pressure if the gas intake is appropriately sized. So far this has been the simplest application with my Eheim 2217 canister.

Mazzei's drop in ports do go down to sufficiently small sizes, and only cost $2.50 USD, but the cap tubes work really well, and If I can cut these with a laser, labor is trivial, and 300 tubes will cost $6.70 USD, and the 1/8" bulkheads are $2.25 USD.

While I prefer the Mazzei injectors folks can buy the Venturi of their choosing screw in the metered bulkhead, and adjust the Co2 flow rate until their tank looks like a glass of Club Soda ! LOL. If it's stupid and it works, is it still stupid ??? Grtz, Prof M