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i would recommend against a valve if you're running diy co2. you will end up losing co2 through the valve, and although it's cheap enough doing it diy, it's still a waste of co2.

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

In one of the AGA magazines, they covered DIY co2. One of the people was big on yeast and cited the faster curve at the outset without it, followed by a slower release later. Supposedly, the baking soda keeps the pace more even rather than the explosive bit at the beginning. It does affect the pH, from what I've read and it makes sense. I thought I'd try it for the heck of it. I can see how long this one gives me 1 bubble every 3 seconds and compare that to a cannister without the baking soda. I'll do that one next.

Baking soda is highly alkaline (high pH). I've not measures, so I'm speaking on speculation alone, but I believe the process of fermentation increases acidity (low pH). The yeast dies if pH is too low. Thus, the addition of baking soda may do nothing more than theoretically increase the life of the yeast.
That is, the yeast does it's "thing" longer.

Of course, I may be dead wrong.

-Wayne

Interesting Wayne. I thought the baking soda would prevent a higher, initial rate followed by a reduced rate. Rather, the baking soda should be providing a steady rate throughout.

I'm going to be watching that as I know for a fact that after 24 hours its still bubbling at 1 bubble every 3 seconds. I'm curious to see if that slows in a few days. I'm also curious to see how long this bottle lasts, with baking soda in it.

I sure hope to see my algae problem disappear

...And to reassure you, the amount of CO2 vented from a small Hagen and/or DIY setup would not be hazardous. If it was, we'd all be dead after the very fisrt soda we ever came in contact with.
Good luck Cory-Di. If you're not happy with the CO2 generation rate, merely dump it out and start over. Sugar and yeast are certainly cheap enough.
I use a 2 liter bottle on a 20h planted tank. I have two 2-liter bottle running on the 55g. The hoses from the two bottles are joined in a metal tee, and the outlet single hose extends into the tank.
At first, I was using baking soda in my recipe, but neer really found any advantage to it. So my current recipe is 1 tsp yeast and 1 cup sugar.

-Wayne

if the mix slows down, just give it a little shake. i usually shake mine about every 5-7 days

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

You mean, I'm suppose to shake the cannister every few days?

This is why you should not use silicone to seal the tube to the cap. I also recommend using tie-wraps around every junction of tubing connections.

I would not be afraid of having a completely sealed DIY CO2 unit. The chances of enough pressure building to actually burst the 2 ltr is slim to none.

My misguided youth showed me on many occasions exactly how much pressure a standard 2 ltr bottle can with stand before bursting.

They will grow to almost 1/2 the regular size before bursting, and IMO you would have to be blind or irresponsible to let such a thing happen.

BTW when they do go....It sounds like a canon just went off.

Seeing as how you should shake the mix every couple of days I would say you would def notice if it was growing in size. Not to mention it's not like the amount of CO2 given off in a day would be enough to cause anything like this.

If it does, release the pressure with the valve and next time I would use less yeast.

I'm a control freak! lol

Edit: If you lost CO2 thru a leaking valve, you need a better valve.

Last edited by Shannen at 24-Feb-2005 14:55

every time i have ever used a valve in my diy system, either the valve sprang a leak, or the back pressure forced open the silicone on the bottle. i would still not recommend using a valve, except for a check valve.

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

Explain how you will loose it, unless you have a leak, you are just creating back pressure. It has to go somewhere in order to loose it right?

Ok, so maybe it wasn't the smartest thing to take brand new, very fresh dry yeast and proof it in 98F water and then add it to 80F water in the nutrafin cannister where the sugar and baking soda were.

That stupid thing that wouldn't run but 1 bubble every 30-40 seconds apparently had bad yeast. I was afraid I'd have to wait another 3 days for the thing to kick in and didn't realize that in less than 5 minutes of putting it back together, I'd be getting 1 bubble per second. Now, some 20 minutes later, its running 3 bubbles per second, no joke.

I used an entire package of Fleischmann's Dried yeast and I don't know if that was too much for that size cannister. I used about 3/4 tsp of baking soda as I couldn't find their stabilizer. Not sure how much they usually use.

I quickly dumped an airwand in the front/center of the tank, afraid my pH might dip at that rate.

Evening is coming. If it doesn't slow, should I pull the end out of the water and just let it run into the basement atmosphere? Dumb question, but can that be hazardous . I can see the headline now, "Mother and Daughter killed by Hagen co2 delivery system".

I also decided to go ahead and add baking soda as some recommended last week or the week before. I just didn't know how much. I decided to err on the side of too little.

I added about a heaping, 1/4 tsp and predissolved it first.

Starting parameters:

pH: 7.5
kH: 60 ppm or 3.36 DkH.

How much can baking soda can I add at once, per 10 gallons, without altering pH too much? Tank is a 20 long.



Last edited by Cory_Di at 23-Feb-2005 18:56

I don't want too much co2. I'm not interested in dropping pH alot . Even if it only went to 7.2 or 7.3, I'd be happy because at least I'd know my plants are getting some co2.

Keep your eyes peeled for a DIY how to on a multi bottle setup from me..

No need to add the valve. At the juncture I was at last night, I decided to pull the plug and start over. I've used only a 1/2 tsp of the yeast this time and just used room temp water as I did the very first time when it took 3 days to start. I can already see it won't be that long before this one starts up, confirming that my original yeast was in bad shape. I verified the date on this package.

I wouldn't be surprised to see it bubbling within a few hours. I'm curious as to how fast it will go. I'd be happy with 1 bubble per second.

I predissolved another 1/4 tsp of baking soda and dosed half of that solution this morning and the other half a few hours later. I'm going to check the kH later.

I'm really thinking of making a big soda bottle device so I can use more yeast and sugar. The Hagen device only holds about a half cup of sugar if you fill it to the tabs. If I can use twice as much in a bottle, then it will run longer. What a shame too because that bottle Hagen supplies is great.

Dried yeast with about 2 cups of sugar lasts me almost 2 weeks.

Di, you should run your CO2 line thru a valve so you can slow down the flow.

That cannister looks pretty solid and should have no problem with what little pressure this will add to the system.

Not to mention, by adding a valve, you will have more control over just how much CO2 you introduce and how slowly you allow the PH to drop.

The pH goes down pretty fast when you start adding co2 as co2 is very soluble. Raising it is a different matter, and you need an airstone to raise it quickly. Adding baking soda means raising the pH, in other words, if you hadn't added the baking soda it would have gone down even more.

Set yourself a target. How much co2 do you want to end with? 20ppm means that with a KH of 3.36, your target pH would be 6.7. Want your pH higher? You'll have to add some baking soda so your starting point will be higher. How much higher? Well, it depends on what is your target pH. for a pH of 7 with 21ppm co2, you need 7dKH (125ppm). That means that before adding any co2 you will raise your pH to about 7.8

Then, next time when you start adding co2, if the drop of pH scares you, just add a third of the amount of yeast you've added now and let it run for 24 hours. Test after 24 hours and add another third of the yeast and wait another 24 hours. Repeat if necessary.

I don't want to scare you, but another thing which I think is important is to monitor the co2 production in the first few days. When I used dried yeast I found out that it doesn't last for long, perhaps a few days, but not even a week. Maybe it was the brand that I was using, but it might be that all dried yeasts are the same regarding that. If it does happen, move to fresh yeast, which (for me) lasts for longer, but starts slower. Maybe other people can confirm this.

I'm positive the yeast was the problem with the first batch - something I just hadn't thought of. I mean, what do you do when the bread doesn't rise - you suspect the yeast. I was looking at everything but, the freshness. based on the dust on the box, it was sitting there a long time.

I'm not sure what to think about the light sea green color. I mean, it matched closest to 6.8. How can that happen in 40 minutes, especially with a Penguin 170, a sponge filter and an airwand running? based on the fish, I have to say it is a false reading.

I didn't think to check pH towards the bottom to see if there was a difference there. All 3 samples were from the top.

EDIT: Well, its an 1.5 hours later and the fish are still fine. Maybe something was bogus with those pH readings. I am now getting something closer to 7.5. I dumped what I had in that cannister and will use the same measurements you did rather than the whole packet. I'm not going to proof it either and see if it starts sooner with fresh yeast.

Last edited by Cory_Di at 23-Feb-2005 20:30

Di, it's a feast or a famine at your place! :%)

The little extra CO2 put out by your cannister overnight will do you no harm at all. If you have a house-plant, maybe you should rest the tube in the bottom of that and see if it grows any better?!

I think taking the tube out of the tank overnight is a good idea. Regular testing of pH should tell you whether you need to continue doing that - test once first thing in the morning before the lights come on, and again last thing before they go off at night.

I have absolutely no idea how much is in a package of Fleischmann's Dried yeast - I usually put between one quarter and one eighth of a teaspoon of yeast in my Hagen canister, and the same amount of baking soda.

this story has me in stitches! At least now you can be absolutely sure it was the yeast that was the problem!

Oh man!! I had to pull the plug. I don't know what the pH was, but just about 40 minutes into this new cannister, my always blue color in the test tube was light sea green . (AP Normal pH tester)

Fish seemed ok, but all huddle on the other side of the tank. I checked from 3 different areas of the tank and it was the same. I couldn't have dropped that fast could it? Would the baking soda have done that? I'm not sure what the pH is.

I think I'll start over in the morning and hope my fish survive that episode.

Last edited by Cory_Di at 23-Feb-2005 19:13

Last edited by Cory_Di at 23-Feb-2005 19:16