co2 injection questions

[CraigG]

I've been reading and I'm confused more then ever. I need to know what the best system to use would be with my current setup.

Here is my current setup.

Tank size: 75 Gallon reef ready
Filter: wet/dry with rio 2100+
Temp: 84.6
pH: 6.0
lighting: 260 watt compact flourescent

Here is what I'm trying to do. I have a decent amount of plants in the tank and it was advised with the amount of lighting I have to get a co2 system.

Well my main focus is fish before the plants. Eaiser to replace plants then the fish. So I want to know what system would be the best to use to maintain the pH around 6.0 and make sure that I don't have the co2 misshaps that I've read about people coming back from work to dead fish.

If you need anymore info just let me know.

[GrillMaster]

It would be easier to just reduce the lighting. Just run 2 bulbs instead of the 4. That would give you plenty of light to grow the plants without c02, Just under 2 WPG, and just use flourish excel with a lil trace and macros every once in awhile.

If you wish to use c02, use a co2 regulator with a solenoid that you can hook up to a timer. That way you can time it to go on 30 minutes before lights on and go off 30 minutes before lights out. This way you wont come home to floating fish...;) :D :D

If ya prefer the fish over the plants, I would tend to lean towards the former. :)

[calihawker]

Have you been to plantedtank.net? There's a lot of folks over there that are c02 guru's. Things I've read that I've never heard about on this forum.

Are you using the overflows into a sump with the wet/dry? Do you have room under the tank for a bit more equipment? Are there any other pumps other than the rio?

Your ph is already pretty low. c02 is going to lower it more. Is that what it is coming out of your tap? What's your water hardness? There's a relationship between ph,kh and c02.

How much money do you want to spend?

Are there specific aspects that you have questions about?

Hope I can help.


Steve

[calihawker]

I didn't see Marks post before I posted mine but I would tend to agree with him. Keep it low tech if possible unless you really want to grow plants.

Let algae be the guide;)


Steve

[CraigG]

Money so much isn't an issue unless its an a crazy price. Under $500 would be prefered.

I want to grow them so I do want to inject co2 but I don't want to risk losing the discus and breeding pair of rams (even though the fry never make it). Don't have room for another tank with my QT tank I'm setting up.

Just afraid of pH shock or co2 overdosing. So just looking for something thats nice, but doesn't have to be the best out there if that makes any sense.

I have gone to plantedtank.net but there is so much information that I can't make sense of it all.

I have the built in overflow and that goes straight into my tank I do have extra room. I made sure to save space cause I knew I wanted to do some sort of co2 injection. Just not aware of what I need, I do know I want to have it able to handle 300 gallon tank when I get mine.

Here is the link to my setup with my tank and fish.

http://forum.simplydiscus.com/showthread.php?t=67171

[CraigG]

Double post there was lag and it didn't show that it posted....whoops

[scolley]

Craig, there is indeed a world of information with regard to CO2 over at plantedtank.net. But, you've already knocked yourself - unknowingly - out of the CO2 arena with your overflow. Probably.

I don't have a snapfish account, so I can't get to the pics you posted (if I'm clicking the right stuff). But it sounds like you've got an overflow with a sump. Great setup, but it usually eliminates your ability to keep any reasonable level of CO2 in the water. CO2 readily "outgasses", or seeks equilibrium with the amount of CO2 in the air. Any disturbance to the surface of the water of a tank with pressurized CO2 will cause CO2 to eagerly outgass. You can run through a LOT of CO2 that way.

Go over to PlantedTank, and do a search on "sump". You'll find that it's done. But not easily. And usually by people that have the tank first, and decided on plants later. It all depends on the amount of splashing your overflow does (most to WAY too much to keep CO2 in your water) and how willing you are to keep refilling your CO2 tank.

Regular replacement will be a problem. And you will probably want to keep an extra filled CO2 cylinder on hand at all times. Because if you are running enough light that you plants MUST have CO2, then when you run out of CO2 the plants will shut down growth, and you can count on the algae to start kicking in within 48 hours. If not 6 or 12.

IF you decide to do it anyway, got over to Rexgrigg.com. He's got some of the best regulators out there. Then you have to decide if you are going to set the CO2 rate by the regulator's needle valve (many do), or if you are going to buy a controller (Milwaulkee being the most popular of the cheaper varieties) to turn your CO2 regulator's solenoid on/off for you based on the pH of your water. Over at PT you'll find links help you determine what pH level you'll set your controller to, based on the CO2 PPM (parts per million) you want, and the KH of your water.

30 PPM is a good level of CO2 concentration for discus. Though some experts here erroneously maintain that it's bad for your fish, that's bunk. It's just a matter of how much CO2. And 30 ppm is more than enough for your plants, and not enough for your fish to care. In fact, you can go much higher than that. I've had it as high as 60 with discus, with no apparent ill effect. What you REALLY have to watch for is HOW FAST you change the CO2 PPM. Though too much - even if arrived at slowly - DOES appear to interfere with oxygen intake, so keep it at 30 until you learn enough to make an informed decision to do otherwise.

Hope that helped. Bummer about the overflow.

[CraigG]

Scolley thanks for the information. If you scroll further down I actually posted pictures in that thread so you can see the setup.

There any spalshing on the return its under the water not much going into the overflow. Only place there is some splashing is when it enters the wet dry.

I did read about wet/drys and someone had a chart that said the co2 loss isn't really that great while there is a loss it isn't as bad. I will find that and post it here.

Here was a system I was looking at and I can get 5lb cylinders in a town by me. http://www.aquabuys.com/miva/merchant.mvc?Screen=PROD&Product_Code=co2_set_dlx_06&Category_Code=i2&Product_Count=6

Here is another I was looking at but not sure why its $150 more.
http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3747+9933&pcatid=9933

[scolley]

Sorry Craig, forgot about the "what do I need" question...

1) A regulator, with solenoid and needle valve (see prior post)
2) A CO2 tank (20lb would be best for you, see your local CO2 suppliers), and check the height of the tank with Regulator on it. It might not fit your stand, and you'll need to get something shorter, like a 10 lb tank.
3) Optionally - a controller - see prior post.
4) CO2 resistant tubing. Best I know if is at Rexgrigg.com
5) A reliable KH test kit. And pH kit.
6) A way to get the CO2 that's coming out of your tubing into your water... see below.

Number 6) above is a loaded question. Many, many huge threads have been dedicated to this problem. In short, you have four options.

1) An in-tank diffuser. These are little in-tank bubble makers that either make small bubbles that move through some type of bubble maze, keeping the bubble moving in the water for a long time so it dissolves. Or makes really tiny micro bubbles, so small they dissolve before they get to the surface.
2) An in-tank reactor. Same idea as a diffuser, but has a powerhead attached to kind of supercharge the process. Allow a single unit to disolve much more CO2.
3) An in-line diffuser. Something in your return lines to your tank that has CO2 tubing attached to it, constucted and plumbed such that CO2 gets disolved in the turbulent water in the diffuser. Most people DIY these very easily.
4) An in-line venturi. Put into your return lines, just like a reactor, with a CO2 line going into it. But the venturi - through some magic of the fluid dynamics engineered into it - causes the CO2 to be rapidly dissolved as water passes through venturi. In this case, the venturi is nothing more that a very specialized tube plumbed into your return lines.

Of the above in-tank diffusers are the easiest, and the least effective. Probably worthless in a big tank. Almost certainly so if you have an overflow.
Next easiest is an in-line diffuser. They are super effective, but you'll probably have to build it. But there are a few available commercially. And the best - by far - is the venturi. But they are non-trivial to set up.

Hope that helps. Good luck.

[CraigG]

Did some more research and from what I read they said a 10lb tank is lasting most people with a wet/dry 7-8 months.

[scolley]

Did some more research and from what I read they said a 10lb tank is lasting most people with a wet/dry 7-8 months.Hey Craig, I must be getting senile! Or need another cup of coffee...

I thought I read that your tank was a 300G! Sorry! I'm getting my posts mixed up.

Yes, by all means a 10g is good for a 75 - assuming no wet dry. Read on...


If you scroll further down I actually posted pictures in that thread so you can see the setup.

There any spalshing on the return its under the water not much going into the overflow. Only place there is some splashing is when it enters the wet dry.

I did read about wet/drys and someone had a chart that said the co2 loss isn't really that great while there is a loss it isn't as bad. I will find that and post it here.I see the pics now. Thanks. I would LOVE to see that Craig. Normally - in some place that is plant specific like Plantedtank - I would never presume to talk about something I had no experience in. In this case it's CO2 on systems with overflows. But since you were posting here, as opposed to where the experts on this topic are, I figured providing you with conventional wisdom was better than nothing. Apologies if I'm incorrect.

However, I'll be really surprised if that wet dry does not - frankly - nuke your ability to keep CO2 in the water. All my cautions about an overflow and sump are mutliplied when that sump has a wet/dry, or trickle filter of any kind - running at volumes suffecient to make it effective.

But I've never done it, and I'd LOVE to be wrong about this, because I'd LOVE a trickle filter. But I'm not willing to give up my CO2 for it. So please do prove me wrong on this. I'd be both delighted, and building myself a wet/dry. Really. ;)



Here was a system I was looking at and I can get 5lb cylinders in a town by me. http://www.aquabuys.com/miva/merchant.mvc?Screen=PROD&Product_Code=co2_set_dlx_06&Category_Code=i2&Product_Count=6

Here is another I was looking at but not sure why its $150 more.
http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3747+9933&pcatid=9933
On a tank your size, a 5 lb cylinder is a poor choice. I've had a 75 without a wet/dry and had to change my 10 lb tank every 5-6 months. Pls don't even think about a 5. 10 or 20 (if it fits) are your only reasonable options.

That Dr F&S setup is a good talking example. It show a lot of the POSSIBLE components of a CO2 rig.

It's got a tank. And a regulator (attached to the tank). And the picture cuts it off, but there should be a needle valve attached to the regulator where the regulator attaches to the CO2 tubing. That is a kind of fine tuning flow rate valve.

You can either fine tune with that, or by a controller (fancy electrical box in the pic) to turn your CO2 on/off based on the pH readings it gets. The regulator has an electronic solenoid (flow on/off switch) attached to it. If the solenoid is plugged in, CO2 is flowing. If not, CO2 is shut off. Rather than plugging that into an AC outlet, and regulating your flow with you needle valve, you can plug it into the controller (which is plugged into a 110v AC). The controller turns your CO2 on/off for you. And if you look a the skinny black wire coming out of the back, it's attached to the blue pH probe stuck to the back inside of the tank.

If you are not confused yet, all I've discussed so far is how CO2 gets turned on/off and to the CO2 tubing from the tank. But how does it get into the water?

In this example there is a method shown that I did not even mention... using a powerhead to feed water to a reactor. The reactor - the thing with the bioballs in it - is connected to the CO2 tubing. And it's connected to a water supply. Water blows through it as CO2 is added, and the turbulence churns up the bubbles until they dissolve, and return to the tank in the water.

This pic shows the reactor attached to the tank, and there is no reason for that. It can go in the stand. Where I would change that - personally - is to eliminate that power head and tank return line. You've already got a return line from your sump to your tank. Just plumb the reactor into that flow of water and you are good to go. That is consistent with my primary recommendation above, but this is a store bought (overly costly and complicated) reactor vs. DIY.

Hope that helps.

[calihawker]

Great info scolley!

Take a look towards the bottom of this thread and you can see the rex grigg reactor I built for my 300. Super simple.

http://forum.simplydiscus.com/showthread.php?t=67255

You will go through more c02 with a wet dry but it can be done. You really have to eliminate excessive splashing though, especially in the overflows.




Good luck!



Steve

[shalu]

I ran CO2 on my 100gallon with Wet/Dry sump for a long time. A 10lb tank usually lasts 4-6months for me that way. I am no longer using CO2 as the constant plant pruning is too much work :)

[scolley]

Thanks Shalu! That kinda puts that question to bed. ;)


PS - is this Shalu is the same Shalu as I know from plant forum, you can take that information to the bank - as reliable a source of info as they come!