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  • Writer's pictureAquaCO2

Where do I get a CO2 refill and should I fill or exchange it

Updated: Nov 26, 2020

Hello and welcome back to another installation of our blog! I know all too well the excitement of getting your new pressurized aquarium CO2 system in the mail and not knowing where to go to get my tank filled up. That’s what were going to talk about today, the what, where, how and even when of local to you CO2 refills!

As you may already know, our aluminum CO2 tanks ship empty. This is because shipping full high pressure gas cylinders is strictly prohibited by postal services. Filling a tank is usually done in one of two ways. If you go to a welding supply shop such as Air Liquide, Praxair or OxyPro they will actually exchange your tank for one that’s been filled at the factory and are located in most large cities across Canada. This way you will get a full 1800psi bottle that has been recently certified. The down side of this is that you may be exchanging your brand new bottle for one that has been used so it may not be in perfect shape cosmetically.

The refill price will depend on the location and how they fill the bottle as well. Oxypro charges me $30 to exchange my 20lb bottle and I haven’t had an ugly tank yet. In fact last time they gave me what seems to be a brand new tank minus the valve on top!

Often wine or brewing supply companies will offer CO2 refills for a good price. They will fill the bottle with... you guessed it, another bottle! The down side here is two fold; you may not receive full 1800psi bottle, instead your pressure will be the same as the parent bottle which may not be 1800psi. The second is that your bottle will need re-certification every 5 years. This cost to re-certify is about $30 and this will save you from trading in your bottle for a scuffed up one. Note- Most welding supply shops only offer 5lb and 20lb exchanges. 10lb tanks aren’t commonly used so they’re not kept on hand by most stores. However in my personal experience if you tell the clerk you’re using the tank in your home aquarium, they may choose a bottle in better condition for you.

That covers the what where and how. Lets talk about when? When should you refill or exchange your bottle? I’m sure you have heard of end of tank dump that risks harming your fish. This happens with single stage regulators when the pressure in your tank drops low enough the regulator does not function properly and excessive CO2 is released into the tank causing wide spread fatalities. Personally I prefer to change my tank out at 300psi. This gives me a week of wiggle room if I am busy, but this plan affords me plenty of room to ensure I will not be harming my fish.

I hope that covers it, and I hope you are thrilled about your new AQUACO2 system! Happy growing!

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