Moved to the General Hardware/Equipment forum so you'll get some responses. I also deleted your other post since it asked the same question.
And as for your question, if you added the ro
water directly to your tank it is likely to drop the pH more, which isn't a bad thing, but it will also drop your KH
which can make your pH unsteady. RO
water doesn't have a buffer to it. Usually people add a buffer of some type to the water when using it in freshwater tanks. I'm sure more people will chime in as to what the best buffer to use is.