Thanks Tom, I'll try and get one. I assume the tee arrangement is OK for the return pump inlet?

Brian, I'm curious about which Mazzei you bought and what pump you have it hooked to.

tefsom85

I think it was a ½" 584. I have a pump (which I need to replace with a bigger model) driving the injector. The output of the injector is then fed to the intake of the return pump.

Well I'm a lot happier!

After sealing the sump return chamber to prevent CO2 loss I gained some improvement but it still wasn't good.
I then altered the standpipe to reduce turbulence and gained another improvement but still couldn't stop all the CO2 gassing off within 4 hours of CO2 going off. It was also taking 4+ hours to build it up again and I couldn't get it below about 25ppm.

After thinking about it I had an epiphany (it's OK, I'm taking medication for it! ) Atmospheric gas was being dragged down the standpipe through the ventilation hose (it follows a Durso design). Wouldn't it be better to pull down CO2 instead. I considered a feed from the CO2 cylinder but then remembered there's CO2 in the sump return chamber.

I routed a 3/4" pipe from a bulkhead fitting in the return chamber into the top of the standpipe in place of the vent so creating a sealed loop. At last, CO2 came up rapidly. I had to go to work in the afternoon so I don't know what it peaked at but when I came in this evening CO2 was still right up, 2 hours after it shut off, and I think I may have overdone it . KH is 7½ and pH is 6.58 at the moment and my CO2 drop test is the lightest of green, almost yellow. I'll have to back it off a lot.

Thanks for your advice Tom.

The tank has only been running a fortnight. At the moment I'm restricting lighting to 2 hours in the evening and changing water every 2/3 days. It's fairly well planted with fast growers (cabomba, ceratophyllum, three types of hygrophila) but I've still got some more for which I'm awaiting delivery. I've put in half a dozen shrimps and 4 nerite snails last week and two dozen small fish yesterday (blank neons and white cloud mountain minnows)

What do you recommend for increasing the light period, an extra hour every week?

Well, good job on the sealed loop, that worked out well.
Another tool for the advice.

I think you can safely add 10 hours of light if the CO2 is good.
Add some excel perhaps, do your 2-3x a week water changes till more plants fill/come in etc

Regards,
Tom Barr

Hello all, I have recently joined this site as I've just started setting up a planted tank and have found the information here to be very useful. I have set up a Dennerle Classic CO2 Professional 300L system and have started looking around for a refilling station, with no luck! I have found a few updates regarding fire extinguishers and was wondering whether anyone has any experience of fitting a standard Dennerle classic regulator/pressure reducer to a standard 2kg fire extinguisher? I'm thinking that I may need to buy a new regulator/pressure reducer should I go down the extinguisher path. Any help would be much appreciated...... Thankyou Mark....

Hi Mark,
I think this thread says so, but the Dennerle regs fit fine on a fire extinguisher bottle (or even a pub bottle). I've got two in use on different tanks, one on a 2½kg bottle, the other on a 6kg pub bottle.

The Dennerle systems aren't bad except for the CO2 diffusors. Mine was a ladder. I dumped it and built the DIY internal reactor Tom designed (have a look in the 'articles' section.

Thankyou Brian..... I'll take a look at Toms design