Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
DIY CO2 is not very much, unless you have at least 3 bottles x 2 liters per bottle going. Rotate them out once a week for the most even supply. By the time you get that scheduled you may want to look into pressurized CO2.
Plants need about a dozen elements to live.
C, H, O are the three they use the most.
N, P, K are the next in line, and are referred to as Macros. In the Estimative Index method they are dosed as KNO3, KH2PO4 and K2SO4.
In a high tech tank you might use quite a bit of KNO3, and little or no K2SO4. KH2PO4 is dosed in smaller amounts.
Ca, Mg are next in line. They are secondary nutrients. If your water has a GH of at least 3 German degrees of hardness then you can assume the Ca and Mg are OK. If you need to raise the GH in the tank use a complete product like Seachem Equilibrium or Barr's GH booster. Do not just use Epsom salt. It only has Mg.
Iron is somewhere in between secondary nutrients and micros. It is used more than the other micros, and is often dosed separately. Chelated iron is good.
All the other minerals are lumped together as micros or trace minerals, and are usually sold blended together, such as CSM+B.
If you want to buy liquids, Seachem makes a complete product line, the Flourish products. They are more expensive for the amount of active ingredient you get.