If you use RO
water you will have to re-dose for the KH
that you would be removing. If you really have 20ppm of NO3
in your tap water, you city is in serious violation of EPA water quality standards. The maximum allowed level is 10ppm. Also, I do not believe that RO
water will change your pH at all.
is typically a waste of time in FW
aquariums. You do want to drive your pH down and the best way to do that would be with CO2
. Perhaps a quick DIY setup. Way cheaper than RO
and you will have better plant growth. Whatever you do, don't try chemical buffers to play with your pH.
My tap is around 8.0 pH, with about 120ppm of KH
General Hardness. I use CO2
to drive the pH down to 6.8 and I have great plant growth:
250ppm of KH
does sound kinda high, but I don't think RO
is a good solution for you.