# How much for pressurized CO2?



## smash (Apr 28, 2010)

I'm new to planted aquariums but after looking at other people's tanks I've become addicted. I've done my research and am probably going to go pressurized within the next couple months. I want to know how much a pressurized system will cost me so I could plan out expenses. If someone could lay down the cost of a system for me (tank 5 or 10 pound, regulator ect.) or send me a PM that would be great.


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## Nanokid (May 18, 2010)

i got my system used for 150 with everthing, tank, regulator, solinoid, but new syestems range all over the place. used except 150 + and new 250 + for everthing. i found Co2 100% worth the price. really makes the difference, that and EI dosing.


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## smash (Apr 28, 2010)

What are solenoids for? I didn't see anything about solenoids during my readings.


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## effox (Apr 21, 2010)

It's an electric on\off switch basically. Plugged in CO2 flows, no power = no co2.

You plug it into a timer so you don't have to turn off your CO2 manually every night (if you are planning on doing so). I left mine on despite having a solenoid just so I had a more consistent PH level during night time.


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## Sharkbait (Jun 15, 2010)

I'd also add a PH monitor. C02 decreases your PH. Your PH monitor will cut off your C02 when it hits a PH that you set. Yay for no PH crashing and massive fish death


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## Kitsune (Jul 17, 2010)

Here's my comments from a previous post:

I got my Milwakee Co2 Regulator from J&L for $90 (Milwaukee ma957 Co2 Regulator). comes with a regulator, needle valve, counter and a solenoid. Not bad for what you get.... (I don't know how long they last though... especially the solenoid part)

I set up mine for:
$60 - Annual lease of 20lb tank
$30 - gas for 20lb tank (I have no clue how long it lasts.. I've been using mine for 3 months and its still good)
$90 - regulator
= $180

Out of this I get a 20lb tank, the tank is on lease so 100% guarantee that the tank is hydrotested (since it is from praxair), and I'll get a 'new' one each time I order the gas.

The diffusion part can be done cheap (many methods online).

_____________________
oh and the pH monitor that Sharkbait is talking about is kind of key too. If you don't watch out the pH is going to drop significantly. The pH monitor continuously checks my pH and will turn the solenoid off if the pH drops below a prescribed level (6.0 for me). My pH monitor is a loner so I'm not sure about cost (i think +$100, if you are looking for a one with a built in switch). Other wise you can just monitor the pH and adjust the KH manually to make sure the pH doesn't drop significantly (you still need an electronic one if you want some accuracy).


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## effox (Apr 21, 2010)

Agreed, if I were to do it again, I'd get a PH monitor as well.


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## Captured Moments (Apr 22, 2010)

One thing you should know about the use of a PH controller is that it is only as useful as you know the KH level of the water. PH varies in function of the hardness level of the water and the Co2 content dissolved. Over time, the KH level changes and you could very well find yourself well below the 25-30 ppm Co2 level when the PH controller suddenly closes the Co2. The PH controller controls the PH but it doesn't directly controls the desired level of Co2. A Co2 drop checker is more useful and you fine tune the bubble rate of Co2 until the 4dkh solution in the drop checker is yellowish green. Then you can read the PH level on the controller and set it at that. If you add buffers or do a large water change, you need to be aware of the potential change in K hardness and affect the accuracy of the PH controller. Too much harness and the PH will never drop far enough despite dangerous levels of Co2 reached , you could end up killing you fish this way.


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## Kitsune (Jul 17, 2010)

Captured Moments said:


> Too much harness and the PH will never drop far enough despite dangerous levels of Co2 reached , you could end up killing you fish this way.


Really? I have heard that you can kill your fish due to the pH dropping too much, I've never heard that the co2 directly kills the fish... I don't think there is any reason for it (since the water will still contain enough O2 for the fish).



Captured Moments said:


> If you add buffers or do a large water change, you need to be aware of the potential change in K hardness and affect the accuracy of the PH controller.


I don't think the accuracy of the pH controller is affected. The level of the Co2 in the water is affected though. There is a correlation between dissolved Co2, KH, and pH. You can find this in chemistry text books, or on the web. So if you are setting your pH contoller to turn off the Co2 at a certain Co2 level, then yes the controller will probably switch at different points because the KH in your tank changes (adding more buffer, changing water etc). But my pH controller is solely used to prevent my pH from dropping too significantly (and also help me adjust the kH as necessary). I don't use it to control the Co2 level in the water.


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## target (Apr 21, 2010)

I got this link from 2wheelsx2. http://rexgrigg.com/ I was quoted about $150 for the set up minus the Co2 bottle. When I decide to go Co2 I would probably rent the bottle.


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## 2wheelsx2 (Apr 21, 2010)

Kitsune said:


> Really? I have heard that you can kill your fish due to the pH dropping too much, I've never heard that the co2 directly kills the fish... I don't think there is any reason for it (since the water will still contain enough O2 for the fish).
> 
> I don't think the accuracy of the pH controller is affected. The level of the Co2 in the water is affected though. There is a correlation between dissolved Co2, KH, and pH. You can find this in chemistry text books, or on the web. So if you are setting your pH contoller to turn off the Co2 at a certain Co2 level, then yes the controller will probably switch at different points because the KH in your tank changes (adding more buffer, changing water etc). But my pH controller is solely used to prevent my pH from dropping too significantly (and also help me adjust the kH as necessary). I don't use it to control the Co2 level in the water.


The CO2 relationship with KH and pH is affected by different buffers in the system. Hence the reason why people use drop checkers. Chemistry is fine (I did lots of chemistry in university and work), but those theoretic formulas are for lab conditions. As soon as you move away from pure chemicals, and include organic compounds, and impurities as inclusions, most of the formulae no longer apply. Such is the case with that pH, KH, and CO2 relationship.

The pH generated by CO2 is transient as it will rise as the plants uptake the carbon (hence the reason why your pH controller would work), but you lack any buffers in the water, the pH would stay down and your CO2 would never kick in, and if you have too much, you'll OD your fish with CO2. So unless you're going low to medium light and you have delicate livestock (like CRS or discus), I would say save your money and get a $10 drop checker and just run the solenoid with a timer.

If you have delicate creatures and you're truly worried about them, then a high tech planted tank with high light and CO2 is probably not for you anyway, as the fish should come first.


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## Sharkbait (Jun 15, 2010)

I use crushed coral as a buffer every few months. Works fine for me. It's strange, because my tap PH is 7.0, but I don't see it effecting my tank water that much when I do a water change. Tank PH is normally around 6.4.

Why do you rent a C02 tank? I just bought mine for $60 (10 lbs). They do a check every time I refill to make sure it works fine.


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## 2wheelsx2 (Apr 21, 2010)

If you're using a buffer, then the KH/pH relationship doesn't work as discussed above.

The reason to rent a tank is that you do not have to hydrotest it every 5 years. Not a huge expense (I think $25) but you need to do without for 24 hours. Most rental places are turnkey, ie, you bring one in and they give you another, so it takes only the time to transport the tank for a change. When Solar was around, the cost of renting a tank was like $5 more than a fill, well worth the difference in price considering the hassles.


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## Kitsune (Jul 17, 2010)

2wheelsx2 said:


> The reason to rent a tank is that you do not have to hydrotest it every 5 years. Not a huge expense (I think $25) but you need to do without for 24 hours. Most rental places are turnkey, ie, you bring one in and they give you another, so it takes only the time to transport the tank for a change. When Solar was around, the cost of renting a tank was like $5 more than a fill, well worth the difference in price considering the hassles.


That pretty much sums it up. Its pretty much a hassle and safety thing for me.
The way i look at it for $60 a year, I am guaranteed a hydro tested tank, and i don' have to worry about the date on the tank. Also transportation is a big thing for me, i'm not 100% sure if a 20 lb Co2 tank is classified under the "Transportation of Dangerous Goods" act, but I'm 100% sure that I won't transport it the way it's suppose to be (transported upright and chained to a secure thing in the vehicle etc). I think a 5lb O2 tank is considered dangerous goods so that's why I'm not sure about the 20 lb CO2 (technically its a non-explosive, non-flammable gas, but its still under pressure). Since they deliver (there is a cost though) I don't have to worry about it.


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## 2wheelsx2 (Apr 21, 2010)

I use a 20 and a 10, and you do have to be careful with a 20, as there is a lot of momentum if it moves.

For $60, I'd rent too, as I do at least 2 fills a year with my 20 lb, and it's $38 each fill at KMS tools (I use Royal city Fire Supply now, which is much cheaper). A lot of places won't even have a lease rate, but just a deposit that you get back when you return it at the end. I think Bevgas leases and is the cheapest source of CO2 around. I own my tanks as I bought them both used so I never did it.


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## Kitsune (Jul 17, 2010)

2wheelsx2 said:


> The CO2 relationship with KH and pH is affected by different buffers in the system. Hence the reason why people use drop checkers. Chemistry is fine (I did lots of chemistry in university and work), but those theoretic formulas are for lab conditions. As soon as you move away from pure chemicals, and include organic compounds, and impurities as inclusions, most of the formulae no longer apply. Such is the case with that pH, KH, and CO2 relationship.
> 
> The pH generated by CO2 is transient as will rise as the plants uptake the carbon (hence the reason why your pH controller would work), but you lack too any buffer in the water, the pH would stay down and you CO2 would never kick in, and if you have too much, you'll OD your fish with CO2. So unless you're going low to medium light and you have delicate livestock (like CRS or discus), I would say save your money and get a $10 drop checker and just run the solenoid with a timer.
> 
> If you have delicate creatures and you're truly worried about them, then a high tech planted tank with high light and CO2 is probably not for you anyway, as the fish should come first.


huh... interesting. Good to know...


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## vdub (Apr 22, 2010)

anyone know how much a 5 and 10 pound tank weighs when full?


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## 2wheelsx2 (Apr 21, 2010)

5 or 10 lbs heavier than the aluminum or steel tank that it comes in.


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