Rex's Planted Tank Guide

Your Source Of Information For Planted Tank Aquariums, Lighting, CO2 & Fertilizers

CO2 For The Planted Tank

CO2 provides carbon, which is a necessary building block of life. If you have a high light tank (more than 3 watts per gallon) then CO2 is not an option but a necessity to keep your plants healthy and growing and keep algae to a minimum. One can either use a DIY CO2 generator or go with a pressurized system. DIY is good for small, lower light tanks. Once your tank size reaches the 30 gallon mark and/or you go over 3.5 watts per gallon a pressurized system becomes a must. I'm not going to cover all the options here so if you have questions just ask. The ideal CO2 levels for a planted tank are in the 20-30 ppm range.

For pressurized CO2 you will need a cylinder. The best places to find a cylinder are welding shops, home brew beer shops, and fire extinguisher shops. I have found that fire extinguisher shops normally have the lowest prices on cylinders. Before you drop a wad of money on a nice shiny new aluminum cylinder make sure you have a location close to you that can/will fill while you wait. If all the shops close to you swap tanks you are going to get a nice rusty steel tank on the first swap so there is normally no reason to buy a cylinder. Again many times the larger fire extinguisher shops can fill while you wait and normally they have about the best price around on CO2.

Be sure to check the price of refills before you get a cylinder. Many times it's only a couple more dollars to fill a 10 lb cylinder over the price it is to fill a 5 lb cylinder. You will also need at a minimum a regulator and needle valve. A few thoughts on needle valves. I have been testing different needle valves lately and I have found that while the Clippard valve works pretty well for most applications there are some better valves out there.

Needle Valves

These pieces should be pretty easy to find for most people at a decent hardware store.
A – Clippard.   B – Swagelok B-SS2-A
C – Fabco NV55   D – Ideal Valve 52-1-11

A few thoughts on needle valves. I have been testing different needle valves lately and I have found that while the Clippard valve works pretty well for most applications, there are some better valves out there.

Like anything else in life, you get what you pay for. Some needle valves are excellent at keeping the setting you adjust it to however there are some that will cause you to constantly adjust on a regular basis. Lets discuss this a little further.

  • Clippard.
  • Swagelok B-SS2-A – This valve can only be run in-line and takes some special hose and barbs. I have the hose and barbs. This valve normally runs about $55 but can be found on eBay as I write this for ~$30 shipped. Much easier to adjust than the Clippard and has a wider operating range. I also have at this writing a few in stock.
  • Fabco NV55 – Much easier to adjust than the Clippard due to the larger knob that has a bit of resistance. I will normally have this valve in stock. Can only be run in-line.
  • Ideal Valve 52-1-11 – Pretty much the Gold standard of under $100 needle valves.These valves are around $75 + shipping. They have 1/8” NPT ports. They are simply one of the best values on the market. I will not be carrying these valves. But you can contact Ideal and order them. If you want you can have it drop shipped to me and I can install in on the regulator I can build for you.

In my opinion the best regulator you can get is either one you build yourself or have someone build for you. It's more expensive but you do get a higher quality regulator. If you want to save a few bucks and buy a pre-built unit then find an Azoo. I know that you can find them at Drs. Fosters and Smith. If not then contact me or take a few seconds and look around the Dr's site.

You will also need a method of getting the CO2 into the water. I use D.I.Y. external reactors. You can buy a nice reactor from either of the above outlets. Or you can buy the Hagen bubble counter/diffuser. If you really want the in-depth knowledge of D.I.Y. CO2 visit D.I.Y. CO2

My D.I.Y bubble counter/gas separator bubble counterRex's gas counter

My D.I.Y reactor reactorRex's homemade reactor

Many people have asked about using a paintball cylinder as part of a CO2 system. While it's possible to use one it's going to cost you as much for the special regulator for that cylinder as a complete normal sized cylinder and All–in–one regulator is going to cost you. Anything is possible if you have enough money. If you really have your heart set on going this way then Red Sea makes a regulator for you, try petsolutions.

I have created a large CO2 chart that covers just about any planted tank pH and kH range. Right click and save to download the file or just click on the link. The file is in PDF format and requires a PDF viewer to view. I recommend Foxit Reader. If you like, you can contact me and I can send you the Excel file CO2 chart

D.I.Y.  Yeast Based CO2

Here are some hints if you are going to go with a DIY yeast based CO2 system.

  • Use juice bottles and not soda bottles. Bigger caps, larger openings, more stable.
  • Drill a hole in the cap smaller than the OD of the tubing. Cut the tubing at an angle. Pull it though with pliers. Done. The seal is gas tight.
  • Get a Hagen bubble counter/diffuser. Just that part. You don't need/want the rest. Use their tubing. It works fine.
  • Use plain old white sugar. I prefer to use wine yeast because it works at the lower winter temperatures I keep the house and it has a much higher alcohol tolerance than bread yeast. And $1 will buy a year's supply. Also when recharging the bottles I pour off the liquid and use the bottle sludge for the next bottle. That's the yeast.