Mazzei venturi

Charlieh

Member
Joined
13 Jul 2009
Messages
29
Amongst other things I joined this forum to try and find more info on using Mazzei venturis so as this appears to be the only specific mazzei/co2 thread forgive me for resurrecting it - my experiences might be of some use to someone. Apologies for the length

I have tried various methods of diffusing CO2 into my (180l) tank and following some success with diy venturis (basically stepped hose connectors cut in half, reversed and re joined with rigid tubing) I bought one off ebay - it has 1/2 inch threads, an internal diameter of approx 4mm and looks just like a mazzei (384?); definitely not a Kent !

To test it I just connected it to the output of my canister (rated 1000l/h but giving approx 500 l/h) and observed. Firstly with no co2 line the performance was pathetic - my diy venturis produced a torrent but this hardly pulled any air through at all! However, when I connected co2 it came out as a very fine dust - better than the diy versions which still gave tiny
(limewood airstone size) bubbles. Flow had reduced to about 300 l/h which wasn't a problem as I use a Koralia for circulation. My setup obviously doesn't generate enough pressure and/or differential to initiate significant air suction but still manages to crush the co2 as, presumably, it is forced in under pressure.

Whilst waiting for some connectors to arrive I just pushed hose over the threads and connected it straight to a spray bar in the tank. Results were excellent - even with the koralia off micro bubbles gently spread everywhere and the plants pearled better than any other method I've tried. Since then, without spending much and with a spare 800 l/h external pump I've tried to improve pressure/differential as per suggestions on the mazzei site but none worked given the low
source flow/pressure. I did manage to get a finer mist by connecting the external in series between the canister and the venturi which increases pressure (add the pump heads) but in my opinion the improvement wasn't worth sacrificing simplicity for extra compexity and power consumption.

So bottom line - the venturi does an excellent job of misting my tank at an economical bubble rate (2-3 b/s) and without extra equipment. It's outside the tank, has no moving parts and should be relatively maintenance free but it does reduce flow significantly. All in all I'll stick with it but will probably try and get a bigger pump or filter when I can afford it.
 

zig

Member
Joined
4 Jul 2007
Messages
686
Location
Dublin Ireland
Charlieh said:
Amongst other things I joined this forum to try and find more info on using Mazzei venturis so as this appears to be the only specific mazzei/co2 thread forgive me for resurrecting it - my experiences might be of some use to someone. Apologies for the length

I have tried various methods of diffusing CO2 into my (180l) tank and following some success with diy venturis (basically stepped hose connectors cut in half, reversed and re joined with rigid tubing) I bought one off ebay - it has 1/2 inch threads, an internal diameter of approx 4mm and looks just like a mazzei (384?); definitely not a Kent !

To test it I just connected it to the output of my canister (rated 1000l/h but giving approx 500 l/h) and observed. Firstly with no co2 line the performance was pathetic - my diy venturis produced a torrent but this hardly pulled any air through at all! However, when I connected co2 it came out as a very fine dust - better than the diy versions which still gave tiny
(limewood airstone size) bubbles. Flow had reduced to about 300 l/h which wasn't a problem as I use a Koralia for circulation. My setup obviously doesn't generate enough pressure and/or differential to initiate significant air suction but still manages to crush the co2 as, presumably, it is forced in under pressure.

Whilst waiting for some connectors to arrive I just pushed hose over the threads and connected it straight to a spray bar in the tank. Results were excellent - even with the koralia off micro bubbles gently spread everywhere and the plants pearled better than any other method I've tried. Since then, without spending much and with a spare 800 l/h external pump I've tried to improve pressure/differential as per suggestions on the mazzei site but none worked given the low
source flow/pressure. I did manage to get a finer mist by connecting the external in series between the canister and the venturi which increases pressure (add the pump heads) but in my opinion the improvement wasn't worth sacrificing simplicity for extra compexity and power consumption.

So bottom line - the venturi does an excellent job of misting my tank at an economical bubble rate (2-3 b/s) and without extra equipment. It's outside the tank, has no moving parts and should be relatively maintenance free but it does reduce flow significantly. All in all I'll stick with it but will probably try and get a bigger pump or filter when I can afford it.

Hi Charlieh, thanks for that, any idea where you bought the mazzei, any links? the 384 mazzei comes in 2 sizes 1/2 and 3/4 inch any idea which one you are using, also what size tubing is on the filter that you have?

The reduced flow rate sounds about the same as if you put a DIY external reactor on the filter, so I could definitely live with that, I thought it would be a lot more actually, I thought you may only get a trickle out of the filter after you put on a mazzei. This was the idea I had when I originally opened this thread basically just use an ordinary high flow rated filter. I think I will give this a try after your confirmation that it works.
 

Charlieh

Member
Joined
13 Jul 2009
Messages
29
Here's a link to where i bought mine from but it was black and £8 cheaper !

http://cgi.ebay.co.uk/Aquarium-Vent...trkparms=65:12|66:2|39:1|72:1694|293:6|294:50

The thread is 1/2 inch with an inner diameter of 16mm decreasing to 4mm at its narrowest. My hose is 16mm internal diameter so I got 1/2 inch female thread to 19mm hose barb connectors from here (you don't get any sealing washers-you can use an o-ring):

http://www.ro-man.com/shop/index.php/cPath/25_137_163?osCsid=8dbe7ded679f2d5b0cdd65f668e1bd59

The co2 connector is a 1/4 inch barb with an internal ball check valve - you can either heat up your co2 line in boiling water and work it over the barb or insert a standard airline connector into the barb as long as it's a tight fit.

Hope this helps
Charlie
 

zig

Member
Joined
4 Jul 2007
Messages
686
Location
Dublin Ireland
Charlieh said:
Here's a link to where i bought mine from but it was black and £8 cheaper !

http://cgi.ebay.co.uk/Aquarium-Vent...trkparms=65:12|66:2|39:1|72:1694|293:6|294:50

The thread is 1/2 inch with an inner diameter of 16mm decreasing to 4mm at its narrowest. My hose is 16mm internal diameter so I got 1/2 inch female thread to 19mm hose barb connectors from here (you don't get any sealing washers-you can use an o-ring):

http://www.ro-man.com/shop/index.php/cPath/25_137_163?osCsid=8dbe7ded679f2d5b0cdd65f668e1bd59

The co2 connector is a 1/4 inch barb with an internal ball check valve - you can either heat up your co2 line in boiling water and work it over the barb or insert a standard airline connector into the barb as long as it's a tight fit.

Hope this helps
Charlie

Thanks mate I will see how I get on, I found a mazzei but he's looking for $50 and $20 postage, I will have a look around and see if I can get one a bit cheaper, the orange one you have linked is usually advertised as an ozone venturi for saunas, so not sure if its the same thing, I will try and find a black one as well.

Second link is helpful ;) I will definitely give it a try once I track down the mazzei.

Thanks again
 

Charlieh

Member
Joined
13 Jul 2009
Messages
29
Hmmm that was interesting !

Just rigged up an Eheim compact 2000 into my return feed in an attempt to increase flow and pressure with the mazzei. My idea was to connect it between the filter and mazzei, remove the canister's impeller and hey presto ..... more flow. To test it I left the impeller in and simply switched off the canister but the results weren't as expected.

My canister (Aqua One CF1000) is rated at 1000 l/h with a max head of 1.8m. It operates with a static head of about 1.2m on my tank and gave approx 500 l/h without the mazzei attached which is as expected. The eheim is rated at 1000-2000l/h with max head of 2.3m so you'd expect that it would increase flow significantly ? Not the case - I decided to be really sad and measure the flow because it wasn't the rush I expected when I turned it on. I tested each combination 5 or 6 times so am fairly confident of my results. They all include the mazzei.

CF1000 only = 288l/h (fine CO2 mist)
Eheim 2000 @ 1000 l/h = 288 l/h (fine CO2 mist)
Eheim 2000 @ 2000 l/h = 324 l/h (very fine CO2 mist)
CF1000 + E2000(@1000l/h) = 396 l/h (extremely fine CO2 mist)
CF1000 + E2000(@2000l/h) = 450 l/h (extremely fine CO2 mist)

Finally I also measured the combined flow with a New Jet 800 external pump rigged in the same way (800l/h max head = 1.2m)
CF1000 + NJ800 = 360l/h (fine CO2 mist)

The flows will probably increase when the impeller is removed or if I connected the Eheim on it's own loop or in parallel with the filter but I'm trying to keep things simple and minimise equipment in the tank. So to be honest I don't think the improvements are worth the extra hassle as the canister filter on it's own produces perfectly acceptable results.

Charlie
 
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