It seems strange to me that you use 90% of RO water and your tank's GH=17.
You may want to check your GH again as well as Ca.
-Oliver
You may want to check your GH again as well as Ca.
-Oliver
Using tank water pH and KH to determine the concentration of CO2 in the water doesn't work. When you have other sources of alkalinity or acidity in the water besides carbonates and CO2, that table isn't correct. I suspect you are low on CO2, considering how much light you have. Why not make or buy a drop checker and use it per the stickie in the DIY forum here? That will work much more accurately.hoppycalif,
the PH is 6.3 and KH is 4
i have enough CO2 all the plants are doing photosynthesis
so i guess its not CO2, i dont use Excel i use pressure gas.
so, what is that major nutrients that you think i am under dosing?