best co2 inject method for 240g w/sump

[Crazy Loaches]

First post here, though I've been on other forums for a while. I will soon be setting up a 240g heavily planted tank, my dream tank. My current plan is to have a sump, probably my 75g tank, with two return pumps (quiet one 4000's). I have heard a few things about the venturi like the Mazzi's and wonder if it would work with my setup. It seems from my reading that sometimes these are difficult to pick and work right, and I dont want to be spending lots on something that wont work, already kinda over budget. The other option it seems that folks use with sumps is to simply bubble co2 into the intake side of the return pumps... will this suffice?

And wondering, due to the size of the tank will there also be any special needs to keep o2 levels up? Will simple agitation at night in the sump via airstone/powerhead be enough?

Thanks for any advice, want to make sure I got a solid plan before I start buying to much stuff...

 

[Tom Barr]

I would use a pair of 1/2 mazzii venturis in the sump attached to 600GPH powerheads, eg a pair of cheapo Rios will work fine.

The out flow from this venturi is fed into the return pumps suction side.

That's all there is to it.
Some 1/2 tubing, the venturis, the powerheads.
The CO2 will be atomized and make no noise as it enters the return pumps.
Most will get dissolved but a little will enter as mist.

You plug the powerheads into a timer and turn the cO2 on about 30minutes prior to the lights coming on and then shut off about 30-45 min before the lights turn off.

It'll be about 2-3 bubbles a second per side/valve.
O2 should not be an issue if the plants grow well, they will add much more O2 than you possible can with any amount of aeration.

The only way to add more O2 than plants is to add pure O2 from a gas bottle.
You can do this also, welding O2 tanks and victor regulator with a needle valve etc and add about 1 bubble/sec 24/7. That should add about another 2-3 ppm of O2.

Many folks by pass the venturi and opt for a fine air stone and place that right next to the return pump suction side, this reduces the noise and produces better more even mist/dissolution.

You do not want the gas to be totally in the gas phase, you wanta nice balance between dissolved and mist.

Venturis seem to do very well there.

For the O2, it's more critical to dissolve the gas which is much harder than CO2 to dissolve(a lot harder).

The O2 gas system acts as a back up and does not displace CO2, unlike aeration.

Aeration adds a lot of noise and evaporation loss, often folks add ugly hoses and stones to their tank for this, and noisy air pump.

For a few$ more, use O2 and then have complete control. This helps the bacteria and fish, not really the plants that much.

I got a Victor O2 reg off ebay for 25$, the gas tank locally for 5 lb welding place for 35$, needle valve for 15$, (actually the reg came with a nice Nupro metering valve, so.........).

But most do not bother with O2.

Plants, good current, large weekly water changes suffice and provide awesome conditions. But I'd suggest using the O2 if you want to amplify anything there.

Regards,
Tom Barr

 

[Tom Barr]

Also, the lok pipe, the flex ball shaped piping they sell will work great for changing the flow patterning in the tank, I'd use that and have at least 2 main sets and 2 tees so you have 4 total directional flows.

Regards,
Tom Barr

 

[Crazy Loaches]

Thanks for the suggestions Tom! I am curious though, after you said this:

Many folks by pass the venturi and opt for a fine air stone and place that right next to the return pump suction side, this reduces the noise and produces better more even mist/dissolution

After reading that it sounds like its the better option then? I currently use a small rena micro bubbler on the intake side of a powersweep 228 powerhead and it mists well. So maybe at least at first this would be a cheaper option, using something like a pair of rena micro bubblers paired with my two return pumps, and there will probably be some mist left over by the time it gets to the tank as well as a good amount that probably dissolves in the 5 or 6 foot long return lines.\

I have looked into that Lok line stuff, but I am unsure. For what I need I think it would be pricey... I am trying to get good current throughout the tank w/o using any additional powerheads or anything. I was thinking about using PVC painted black with krylon fusion which others have reported being able to use in thier aquariums. I could make a custom spraybar, I havent worked out the details but I could probably design something that would work well. But then again I guess the Lok line would be easier to change to perfect the flow later.

About the O2, I am not really sure, as I recal you used that on the behemoth? I do plan on it being heavily planted so there should be good levels of O2 there, but I also plan on it being heavily stocked. I like fish to, though many focus on just the plants, but I like both. And most loaches are claimed to have hieghtened O2 demands though in previous CO2/O2 mishaps my SAE's seemed more sensative than the loaches. But anyways, my stocking will inlcude about 6-8 Clown Loaches, many Zebra Loaches (currentl have 7), and I am thinking of including a group of Bala Sharks(not sure, maybe 6) and maybe Pearl Gouramis(again not sure, probably a large group 8-12). I'd be willing to put in O2 system but only if you think having this stocking might need the extra O2 over what photosynthesis will provide.

~Tristan