Planted Tank Obsessed
Join Date: Dec 2012
Location: In an aquarium nearby
I don't have a TDS meter, don't know if that's high or not. RO water has the advantage of just adding the stuff you need and leave out everything else in the proportions you want.
You can add just about anything you need increased. Baking soda for kH only, Ca&Mg for gH only. I found a lot of plants do well in low kH with CO2 gas. Some of them tolerate a high gH. Be warned that once you mess with these parameters you should *slowly* change them. I had mysterious melts from abrupt changes in gH. But also growth spurts I haven't seen before.
Limnophila Sessiliflora did well with just RO water and nothing else but Limnophila Aromatica stunted until I added Ca. after that it grew fast and bushy with lots of side shoots.
If you do decide to use only RO water start by mixing your normal water then slowly increase the percentage of RO but monitor the gH especially and supplement as required once you get to RO territory.