# DIY diffuser - $2(HOB Filter)



## desjardo (Aug 30, 2008)

So I had a brain wave. Why not put my c02 into my HOB filter. OK, so I start looking and decide If I can fit a check valve on the down side of the intake then it may just work! 
So first things first....
Find check valve - Dont want the yeast sucking out of my 2L
Voila...It will fit in the unit!(Gonna be close but I think It will fit)
Now I have....








So now that I have it hooked up I do a bubble test.....
I blew into the unit very hard(way more than c02 will) and it made some noise but zero bubbles are getting out! Nothing....
Does this mean I have 100% diffusion?
If so this works great. When the yeast is working it I hear nothing but a slight trickle of air...amazingly simple!
Heres another view...


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## ameekplec. (May 1, 2008)

great idea, but the problem with using an AC is that the surface agitation will cause you to lose a lot of the CO2 you've got dissolved. This DIY, while fairly common, works better with a canister where you can have the spraybar or return below the water's surface.


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## desjardo (Aug 30, 2008)

Yeah, I knew that already but was previously using an airstone. This is way better than an airstone, and works great on a student budget... But if someone want to donate a canister I am always down for donations...lol
Main thing on this is budget c02, saves me on excel(use 1/2 dose) and keeps me entertained..


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## sawman88 (Sep 29, 2008)

when i had dyi co2 i stuck it in the intake of the canister. with co2 i think surface agitation is your enemy. ive seen a flower pot turned upside down or somthing simular used. i think its a bell. is what they call it. you can buy them but im sure something could be rigged up.


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## desjardo (Aug 30, 2008)

This is a 20 gallon low budget planted tank. I do not want a bell in the tank, but will later consider a diffuser although if my c02 levels go high enough with this why waste money?
Yes surface agitation is the enemy but so is cash, student here.
Wheather I have a diffuser or not this tank needs filtration and will still have an HOB.
Also the flow of water coming off is such that I doubt there is hardly any loss. I just think that if there are no bubbles I must be getting better diffusion than what I had b4. I cant see me losing all the c02 from such a small waterfall. Yes there are better ways to do it but there always is and they all cost $$$$ or look awful. This is in my living room.
I am gonna continue for a week and check c02 levels again then.
If my levels are higher than they were than I am happy. The higher it goes with my yeast and $2 hob, the less I spend on excel!
If someone knows where i could find a glass diffuser locally though that would be great..


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## ameekplec. (May 1, 2008)

sawman88 said:


> when i had dyi co2 i stuck it in the intake of the canister.


A HA!! You do have a canister!

Canisters 1, Sawman 0


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## sawman88 (Sep 29, 2008)

lol yes i do have a canister filter. its an ehiem... the double stack one. not sure what its called. its pretty sweet been running non stop for about 3 years now. i like them i never said i didnt. but im not going to go buy 20 canister filters for all my fish room tanks.


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## Canadiancray (Apr 27, 2006)

This is TOTALLY counter productive. Surface agitation can strip a tank of CO2 far faster than you could ever hope to put it into the tank. Stop waisting your time. Forget the CO2 until you can do it properly.


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## sawman88 (Sep 29, 2008)

just for arguments sake. what is the co2 levils? with and with out the co2? that way then we know for sure


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## hojimoe (Mar 7, 2008)

wont matter co2 in any AC filter is useless, much better with the airstone you were using before! 

Another note, I use a simple rio50 pump (venturi style)...I see the bubbles, but it works great with pressurized, high PPM all the time with low bps (can't remember what I have it at...pearling each and every day!


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## desjardo (Aug 30, 2008)

When I previously did test on the c02 levels(according to the ph/kh test - Also - is this test even accurate?) they were sitting anywhere from 2.9 to 6.
I will test again soon. How long should I wait?
This tank is going to have a hob filter probably as long as I have it. So how is the surface agitation a factor if it doesn't change in setup A - airstone, or setup B - Intake ?? This tells me that unless I own a canister, C02 is useless. Yet I see people all over planted forums running C02 and HOB. Can someone clarifiy 4 me please..



Also - is this test even accurate?

****Please don't ask me to go buy a c02 measuring device****
LOL


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## PPulcher (Nov 17, 2006)

There are some inaccuracies with the kh/ph method, but I figure it's 'good enough' for most applications. If you use buffering agents or peat filtration, the results will be messed up. At any rate, your plants will let you know if they are happy.

If it's working for you and you are happy with the results, go for it! One suggestion is to keep the water levels topped up so that splashing from the HOB filter is minimal.


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## desjardo (Aug 30, 2008)

Well the water level is as high as I can keep it at all times, and the plants are doing amazing. I took a day one pic and will post when I do the one month pic. I have had an issue with green water since starting this tank so I havent been feeding the plants anything but I have had the DIY c02 and airstone, running until it clogged up, and been doing frequent water changes. Doesnt seem to be helping. Wondering if I should try black out... Dont want to though as I was hoping the plants would clear up water in time.
Patienece I guess.


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## desjardo (Aug 30, 2008)

OK. I had my c02 disconnected for a while so based on my tests heres what I've got to start with;
PH - 7.6
KH - 5 Degrees
So this tells me that with no c02 my levels are at 3.768

Wow. That is low! Going to plug in the c02 and check at same time each day for the next few days.
I will post my results.


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## tendril (Oct 19, 2006)

Folks, I used to inject CO2 into my aquaclear with good results. It's entirely possible to maintain an adequate CO2 level with HOB filter injection. However, you have to be _very _diligent about keeping your water level topped up in order to minimize surface agitation, which makes it less reliable than injecting into a canister, particularly if you are using DIY yeast CO2.


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