Upgrading CO2 Cylinder

Hey all, I am a noob when it comes to CO2 and I just got this set about 3 weeks ago

» CO2 Aluminum Cylinder Supply Set / 1L – Professional

I noticed that I need to run a fairly high BPS ( at around 2~) for my 40 gallon long tank. The tank is about 1/3 done now, so I think I'll need to refill in less than a month. I'm wanting to upgrade the cylinder to something bigger (I think 1L is about 2LBs).

Thing is, I am not sure what to look for in cylinders... can I buy any kind of CO2 cylinder that is big enough to my liking? Or should I be looking out for thread sizing, etc...?

 

C02 is standardized in the beverage industry. When you make the move up from the cheap little aquarium stuff, you go next to your local beverage supply place and they will set you up.

I use a 2 pound bottle from Roberts Oxygen. Lasts for years. When it runs out, you bring it in and they just replace with a new one fully charged. Bring in your regulator and they will set you up with the connections if you need any adapters.

 

2bps is not high. I have a 40 gallon breeder, and I have a 5lb tank which lasts a few months. I run my CO2 at least 5bps but honestly I’m not sure because it’s too fast to count without taking a slow motion video. I just upgraded to a 10lb tank which should last around 6 months at least. If you look online for a quality tank, a 5lb should cost you around 50-60 bucks and a 10lb tank around 100-120. From my experience, people who buy CO2 tanks in person usually get ripped off. I would highly recommend having at least a 5lb tank for a 40 gallon.

What is your KH? Mine is 6-7 which is why it probably takes me a good amount of CO2 to drop my PH. Also, how are your measuring CO2 levels?

 

Thanks for the reply, I’m actually using two drop checkers, one on the left and right of my tank. I’m not sure what my KH is for my water, I only have the regular API Freshwater test kit but I may go and get a test for KH. Does high KH mean harder for co2 to drop pH or lower is harder?

 

CO2: Striking the balance

Higher KH means higher pH for the same C02 level per the table.

But the KH does not change the C02 concentration.

We used to use pH and KH as a way to estimate C02 levels, but the drop check test is more reliable since other things in the tank can affect pH other than just C02.

 

Thanks for the reply, I’m actually using two drop checkers, one on the left and right of my tank. I’m not sure what my KH is for my water, I only have the regular API Freshwater test kit but I may go and get a test for KH. Does high KH mean harder for co2 to drop pH or lower is harder?

Yeah, the higher your KH the harder it is to drop the PH. Generally also the lower your KH is, the more sensitive plants you can grow successfully.

While PH is a function of several factors, measuring PH right before CO2 comes on and then after 1-3 hours of CO2 injection is the best way to gauge CO2 levels in the tank, along with monitoring your fish for signs of stress, and avoids confounding factors like buffering. I would definitely recommend testing your KH. If you’re between 1-10, you’ll want to aim for a 1pt drop to start with. You could potentially get up to a 1.3 drop if you have enough oxygenation/surface agitation in your tank.

I would highly recommend this website in general and these links as a resource for planted tank information:
The wrong way to read the pH/KH chart.
Surface agitation & gaseous exchange in CO2 injected tanks

That website was started and is run by Dennis Wong, a professional aquascaper and a huge name in the planted tank hobby. Also, Joe Harvey, who has won and placed in the top 3 of one of the biggest aquascaping competitions in the world for 4 years straight also advocates measuring CO2 injection by measuring PH right before injection and then within 1-3 hours after its been injecting.