DIY CO2... Worth it?

[Biggen]

Hey guys. I was wondering if it would be worth my time making two DIY CO2 kits. This would be for my 40 gallon tank. I have been doing a lot of reading and it looks to me that CO2 really needs to be in the water for a bit before it diffuses into in. Simply putting the hose in the bottom of the tank and letting the CO2 gas rise to the surface wouldn't seem to make much of a difference. Would putting an airstone on the end of the tube help matters any? What about a diffuser? Could I put one of those on the end of the tubing? I have also read that you can put the tube under the filter intake. This would allow the filter to "suck" up the CO2 and churn it up inside the impeller. Of course then you run the risk of cavitation...

Or should I simply buy two of the Hagen CO2 kits. They are only around $20 each. I may spend that in materials building the DIY kits.

 

[d9hp]

Well, you wont spend 50 bucks on DIY CO2, maybe 4 bux. I have a hagen system, and because of the diffuser, it is worth it.

 

[Biggen]

Yeah the only downside to the DIY CO2 that I can see is that I might not be able to properly diffuse the CO2 into the water.

How well does a simple airstone work for this purpose? And would the Hagen diffuser work better than the airstone approach?

 

[d9hp]

The airstone would not help much. The hagen diffuser is really well engineered. Also, if you do they DIY route, you can always have the bubbles go into the intake on your filter.

 

[Biggen]

Ok. Well I went ahead and bit the bullet. I just purchased two of the Hagen CO2 units. I figured that if I build it myself and it ends up doing no good (which is what probably would happen) I would buy the Hagens anyway.

Ok. Now I know that introducing CO2 into the tank will affects its water chemistry (i.e. lowering the pH). In order to try and avert that, can I introduce some small pieces of coral into the tank? Wouldn't they help buffer the tank so that the pH doesn't fall? I course this would mean trial and error when determining how much coral to put in. But I could start with a smaller "chunk" and go from there.

What do you guys think? In fact, what do you guys do in order from keeping your pH from falling? Do you let it swing (which I would think would be bad for the fish) or do you attempt to stabilize it?

 

[targaboy78]

Hi Biggen,

In the User's Guide of the CO2 unit.

When CO2 dissolves in the water, some carbonic acid is formed which will tend to reduce pH and KH. Test these parameters regularly and try to maintain pH values of 6.8 to 7.0 (slightly less or more is permissible) with a KH range of 70 to 90mg/L. Adjust KH with Nutrafin pH Stabilizer. This will provide natural bicarbonate buffering to stabilize pH while furnishing plants with potassium, an important macro-nutrient.

So, long story short...
- Buy some Nutrafin pH Stabilizer (KH Booster).

IMHO, don't start by putting the hose on the lowest setting, try either the middle or the highest setting first and see how it affects your parameters. The lower the setting the more time the CO2 bubble will be in the diffuser, the more CO2 dissolves in the water. (Too much CO2 is toxic to fish.)

Also, try to keep your surface agitation to a minimum. The more agitation, the more CO2 you will lose in surface gas exchange.

I hope this helps.

 

[Biggen]

Heya Targaboy78,

With the pH stablizer I would add it with every water change I do, correct? So I would add two things to the water for every change: dechlorinator and pH stablizer. Correct?

 

[targaboy78]

Hi Biggen,

Not necessarily. Test your water pH and KH to determine your tanks requirements. Sometimes, you won't need to add anything more than dechlorinator.

I test my pH and KH prior to my weekly water changes, then if they are within parameters, I would only add dechlorinator and liquid fertilizer (my tap water has a pH of 7.0).

To date, I have always needed to add the pH stabilizer because my KH is always low. (the pH stabilizer is also a KH booster).

I always add a liquid plant fertilizer to my weekly replacement water.
I use KENT Freshwater plant and KENT Pro*Plant.

This is what works for me. Bear in mind, that I am on the other side of the continent (diagonally). Water parameters, avarage temperatures, other factors MAY come into the equation. (Maybe not? - I don't know)

 

[Biggen]

Hmm...

I guess then that KH and pH are related to one another in so far as when the KH drops the pH should drop as well. I suppose there is a KH level that is "normal" and anything below this range could lead to the pH of the water falling. Is this correct?

I currently don't have a KH kit but I am sure my lfs has them in stock. I suppose I need to get one (after introducing CO2) in order to determine if I would indeed need to add the stabilizer to the tank...

Of course even if I didn't have one it wouldn't make much of a difference would it? If the pH is low (i.e. 6.0) couldn't I still put in the pH stabilizer even if I didn't know the KH level? Assuming that pH and KH are proportional, KH would be low if the pH is low as well, correct?

I hate chemistry...

 

[shawmutt]

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm . This site helped me out a lot, it even has a handy calculator to calculate totals (I stole the formula and put it on my excel so I can do it myself ) Unfortunately I can't help you with the pH buffer, because I have a black water tank that needs very soft acidic water, and the C02 is making it easy. I hooked up a DYI system from http://www.netpets.org/fish/reference/freshref/co2.html , with a few modifications:

1. I used the two bottle method he mentions, but I plug them both into a gang valve, and run one line out into the tank. This mainly does two things, it equalizes the pressure in both bottles, keeping the bubble count the same-and the gang valve can act as a pressure release it the bubble count is too high.

2. I put an airstone under the gravel bed, and under my jaguar skull (see my gallery), the skull has a pocket that catches the bubbles and helps them diffuse.

It's been a week or so, I noticed a change in the PH almost immediately. I'll get those cardinals to breed yet!

 

[Guest]

So you got the hagen system, good call biggen.

I have a couple questions.

What is your ph from the tap? What kind of fish are you keeping?

I ask these because I run 1 hagen on a 25 gallon tank and it only drops my ph from 7.4 at the tap, to 6.8 in the tank. Of cours your water may need more buffering, I have no way to tell. Much of this depends on what type of fish you want to keep.

After doing extensive reading on different sites, the general consensus has been that you can't really kill your fish with DIY co2. Pressurized co2 is a different story.

 

[Biggen]

Hey Shawmutt,
Thx for the link to that site. Great info located there...

Hey Corvuscorax,

Yeah I decided to go with the Hagen. I figured that just the diffuser I would be getting would make the purchase worth while. Plus they give you 3 months worth of "activator". Can't beat it for the price... I went ahead and bought two since the tank is a 40 gallon. The only thing I hope I can do with it is keep the reaction chambers under the tank. I really don't want to hang them on the side. The reason I got the Eclipse hood was to give everything a sleek looking design. Having two large canisters hanging on the side of the aquarium kind of ruins that picture.

My pH from the tap is 7.1. I am planning on keeping danios, rainbows, gouramis, barbs, corys, etc... All community fish. I was going to go the livebearer way with guppies, but then I found out that planted aquariums don't like salt!! . So I decided against it.

I, too, have been doing a ton of reading. The only thing I have found out, definitively, is that introducing CO2 to the tank will cause the pH to lower. However, a lot of people say that my water will not have pH swings. I will simply have a lower STABLE pH with CO2. I think the only way to know for sure is to get the plants into the tank and then measure the pH of the tank over a couple of days. I believe I need to measure the pH before I turn the lights on in the morning and before I turn them off in the evening. If the pH swing is negligible (i.e. 5 or so) would this be cause for concern?

I do have access to tons of coral and seashells. So if I need to add a buffering agent to the water, than I can. However, through my readings I have also found out that by adding an object to the water that releases carbonates, putting in CO2 can actually cause the pH to go up. I dunno....

I just want it to work.

 

[Guest]

OK, here's the deal. If you havent set up both hagens yet, do it like so. Set up 1 now, and 1 in a week. this is so you change the mixture on an alternating basis, keeping co2 levels more constant. Hope thats clear. Test the ph daily at first, then once in a while. You can do the morning/evening check, the swing shouldn't be very much. The fish you listed should do fine with this, I don't keep all species you listed, but have seen them in many planted tanks with co2. Start out with no buffer, the simpler you keep it, the less there is that can go wrong.

I just want it to work.

It Will!


Also, when you run out of packets, its simple to make your own mixture, and cheaper.

1 cup sugar
1/2 teaspoon baking yeast
1/2 teaspoon baking soda (stabilizer)

All can be purchased in the grocery store cheaper than the hagen packets.

Oh yeah, 50 kudos to you for doing all your research!

 

[Biggen]

Oh yeah, 50 kudos to you for doing all your research!

YAH!!! 8). Thx bud.. I HAVE been doing a lot of research. Just ask my wife.

Staggering the changing of the ingredients is a great idea. I will definitely do that.

I will also wait on the buffer like you suggested until I see what is going on with the pH. Hopefully I will have a high enough KH content that my pH won't drop dramatically. And with regular water changes the pH should never fall too much.

Everything will be coming in on Wednesday and Thursday. Hopefully by Friday I will have the system up and running, sans the plants and starter fish. I will post some pics so that you guys can check it out.