DIY Diffuser

androo303 · January 09, 2012, 05:50:34 PM

Hey all,

Well I've made what looks to be a plastic pipe bomb for diffusing co2 into my tank. I made it using plumbing grade PVC and glue. While I have installed a check valve on the unit via hot glue, should I submerse this diffuser into a bucket of water and bleach to disinfect? Also, if I submerse the unit with airline check valve, will the valve get ruined or will it be OK?

Probably a simple question and answer that I should know, but I just don't want to throw the effort and $$$ away because of something stupid I did.

Cheers!!

delslo · January 09, 2012, 07:06:05 PM

I made mine the same way in the past, but I never checked or disinfected it. Never had any problems with the tank, just make sure that there is a valve on either side of it so that you can take it out periodically to clean it (I take it you used bioballs to diffuse the co2?). The valves were the one thing I regretted not installing.

androo303 · January 09, 2012, 08:38:19 PM

Thanks for quick reply. I dunked it into a heavily diluted bleach/water mix and will hook it up tomorrow. The only thing I a, worried about is over dosing with my less then precise needle valve from HD. What bpm/bps should I shoot for to start off?

Quote from: delslo on January 09, 2012, 07:06:05 PM
(I take it you used bioballs to diffuse the co2?).

Yes I threw about 10 bio balls in it.

delslo · January 09, 2012, 10:16:24 PM

Quote from: androo303 on January 09, 2012, 08:38:19 PM
Thanks for quick reply. I dunked it into a heavily diluted bleach/water mix and will hook it up tomorrow. The only thing I a, worried about is over dosing with my less then precise needle valve from HD. What bpm/bps should I shoot for to start off?

Yes I threw about 10 bio balls in it.

Start low and gradually bring it up over the course of the week checking the pH constantly. CO2 causes a drop in pH so keep an eye on it. Just remember that at night your plants release co2 so that will be your peak co2 period if you don't have it running on a solenoid.

dan2x38 · January 10, 2012, 01:16:48 PM

I'm guessing you're using the check valve to connect the CO2 input to? Using hot glue on PVC will not work! You are looking for big leak seriously. The check valves are made of hard plastic that doesn't glue to anything it must be welded.

I used a brass 1/4" barb from Home Depot for $2.99. On one end it is threaded 1/2". I used a drill bit between my fingers and made a careful hole smaller then the threads. Then with great patience and some trial and error managed to thread it into the pipe bomb. Then I attached my air line with a check valve inline to prevent water flowing the wrong way.

In DIY CO2 diffusers and reactors the common mistake is trying to glue the plastic to a another plastic component in the design. They at best create an air leak and you loss your CO2 at worst the leak creates a serious mess and loss of livestock plus burned out heaters, power heads and filters from running dry. It is not worth those losses or risk of them to save the cost of a decent diffuser. But you can design a safe one if you research the pit falls.

One other note the longer the pipe bomb the more dwell time with the CO2 for best diffusion. You can also place the input at the top with the CO2 entering at the same end. Then have the water exit to return to the tank at the bottom. This allows for the longest possible dwell time. I did this with my pressurized and DIY reactor and got excellent diffusion. If there is an issue priming it inline just tip it to get started. You can place on a 45* angle instead of straight up to make it easier to prime and more water flow too.

androo303 · January 10, 2012, 08:30:24 PM

Great information!!! Definitely don't want to leak out all my water to the tenant below...

Would you suggest a JB weld type formulae or the PVC glue that is available from HD?

dan2x38 · January 10, 2012, 08:41:17 PM

Quote from: androo303 on January 10, 2012, 08:30:24 PM
Great information!!! Definitely don't want to leak out all my water to the tenant below...

Would you suggest a JB weld type formulae or the PVC glue that is available from HD?

I suggest non because you cannot glue plastic. The check valves are made of plastic and it cannot be attached with glue. You use a screw in fitting then use Teflon Tape (not tape actually) to seal it from leaking. I asure you if you try to glue it there will be a leak and a mess no question or doubt about - period!

androo303 · January 23, 2012, 08:01:29 PM

Quote from: dan2x38 on January 10, 2012, 08:41:17 PM
I suggest non because you cannot glue plastic. The check valves are made of plastic and it cannot be attached with glue. You use a screw in fitting then use Teflon Tape (not tape actually) to seal it from leaking. I asure you if you try to glue it there will be a leak and a mess no question or doubt about - period!

Well, thanks for the heads up!!! I went out and bought an angled union pipe and then attached a screw on barb so that I can put my air hose onto it.. Yippe!! Crisis averted. Now I need a one way valve as I broke the one I had when taking it out...

dan2x38 · January 24, 2012, 06:17:26 PM

The cheap check valves come apart in short time when exposed to the carbonic acid created by the CO2. Those cheap green plastic check valves get soft and the tip just breaks away causing a leak. I used a plastic CO2 check valve I ordered from Big Al's. They were from Red Sea they lasted for well over a year might even still have some somewhere after I shut down my planted tanks? They had to order them for me likely have to do the same. They cost more but again a couple dollars are worth saving a serious spill, cracked heater, burned out filter from running dry and a bunch of dead occupants - at least in my whacky thinking.

http://www.bigalspets.ca/Red-Sea-Check-Valve/dp/B0061SIH00