[Chris333]

I'm currently using a glass/ceramic diffuser in my 15g tank and there are tons of bubbles in the tank. Wanted to put the CO2 into the Aquaclear like I have seen a few different places. My question is would I still have bubbles in the water that way?

Thanks.
Chris

 

[DarkCobra]

Very few to none, if you raise the standard filter sponge to a higher position in the basket. That way, CO2 bubbles get blown underneath, trapped, and slowly diffuse; rather than bouncing off the side of the sponge and then floating up and out of the overflow holes to be ejected.

 

[Chris333]

OK so I did it. I used a Discard-a-stone laying flat and drilled a new hole for it leaving the purge hole there. The bubbles out of the stone aren't very fine, but they are all going under to the media area, so that is good. I used a sponge with a half sponge under it and as you hopefully can see there are bubbles collecting under the sponge.

So it this OK? The tank is fine with waaaaay less small bubbles than before. Everything looks good to me, but is there anything I can do it improve on this?

Thanks
Chris

 

[DarkCobra]

Looks good to me too. Can't think of any further improvements.

 

[kingdave]

Have you noticed an improvement in efficiency of CO2 use with this method compared to the ceramic diffuser? Did you need to adjust the bubble rate up or down to maintain good CO2 concentration.

I'm wondering if the CO2 might offgas as the Aquaclear delivers the water back to the tank across the surface and might be less efficient.

 

[Chris333]

I have a drop checker in the mail right now so I can't answer that yet, sorry.

 

[kingdave]

No problem... Please keep us updated once you get your drop checker.

 

[Chris333]

Well the drop checker is here, but it didn't come with the "special water" so I'm waiting for that now...

Anyways. I'm still getting very fine bubbles all throughout the tank. I moved the CO2 inlet to the suction tube of the AC so the impeller would chop it up. And I'm still getting bubbles. So much that the tank looks cloudy.

Is there any way to get CO2 into a tank without bubbles without using a canister and in-line reactor?

I'm currently running the CO2 at 1 bubble per second.

 

[DarkCobra]

Hmm.. Some ideas:

Make sure the water level is high. Otherwise, the HOB outflow will drive bubbles underneath from the surface. That's the only thing that causes bubbles in my setup.

Remove that small sponge segment at the bottom. The spikes in the basket sides will still hold the sponge in the higher position. That may give more area for CO2 to spread out, and reduce bubble ejection.

 

[Chris333]

I'll try the sponge trick. Water is right up to the rim.

 

[Chris333]

Well that isn't working either. Same result.

The drop checker is not working and the color looks right if not maybe a little low on CO2.

 

[Jim Miller]

I've got a 10g with an AC20 HOB. I have a cheap Aquamedic regulator on a 24oz PB cylinder with a GLA 45mm in tank diffuser. The needle valve on the regulator is completely closed and leaks enough at that setting to keep my drop checker at a nice lime green. Not doing any gymnastics to try to optimize results. It just works.

Jim

 

[Chris333]

So you are saying those diffusers work better than the glass ones? I just switched back to my glass in tank diffuser, but that was problematic to begin with.

 

[Chris333]

BTW my water level is 1/2" lower than it was yesterday! I need a lid.

 

[Jim Miller]

My tank is nothing special. It's a cheapo 10g with an incandescent lid that I've put 2x13w CFLs in. It was intended to be a QT tank but I've started putting plants in it. They're growing very well now that I put in the little CO2 addition.

I'm not saying anything about better or worse. I'm just saying how mine is working. BTW, there isn't a lot of mist coming from the diffuser yet I'm getting a nice lime green. I don't turn it off at night rather leave it running all the time.

Jim

 

[DarkCobra]

Sorry it didn't work out. No clue at this point what the problem might be. I've fed CO2 into two different AC20's and an AC70, and always had good results.

 

[Chris333]

This is an old 10gal of mine with DIY CO2 and glass diff.

Back then I didn't get many bubbles. Now I have PSI tank CO2 that is on a timer, on during the day only.


Dark Cobra, Is your CO2 feed into the filter through an air stone?

 

[DarkCobra]

I don't use airstones when injecting into a HOB. Instead, I cut the airline at an extreme angle; so if you look at the opening, it's roughly a 1" long oval. Then use zip ties to secure the opening to one side of the intake.

Between the shape of the opening and the suction of the filter, this naturally shears CO2 from the line in tiny bubbles, about 1-2mm in diameter. Not as small as from a fine airstone in peak condition, but it's consistent forever with no worries about clogging changing the bubble size.

Will take a picture if the description isn't clear.