Do you think that if a plant tanks pH is routinely stabilized between 7-7.2, that there will be sufficient CO2 present to meet the needs of the plants?
It depends on the amount of carbonate hardness (KH) present. KH, pH and CO2 have a fixed relationship as long as carbonate is the only buffer present (no phosphate buffers like pH-UP and- DOWN, Discus Buffer, etc.). You can determine CO2 concentration by measuring pH and KH and using the table below. An optimum level of CO2 is 15 ppm; a good range is 10-20 ppm. Keep in mind that good CO2 levels also require good light levels and proper nutrients and trace elements to be effective. All things must be in proportion. The El Cheapo Tetra KH test kit is as good as any and is actually more useful than more expensive “alkalinity” tests kits for this purpose. A pH test kit with a resolution of 0.2 units is also suggested. Pay close attention to the accuracy – if the KH kit is accurate to +/- 0.5 dKH and the pH kit is +/- 0.2 units, the range of CO2 values is quite large. Let’s say you measure 3 dKH +/- 0.5 and the pH is 7.0 +/- 0.2.
Related Questions
- Do you think that if a plant tanks pH is routinely stabilized between 7-7.2, that there will be sufficient CO2 present to meet the needs of the plants?
- The Gourami have been in the tank for about 2 weeks now. Do you think it is OK to leave them with the elevated PH?
- Other than bottled CO2, what is another acceptable method of adding carbon dioxide to my 55 gallon plant tank?
