The problem with RO
water is that all the minerals are removed. It's almost like distilled water. That means no GH
, no KH
, both of which can be tested for.
Shrimp keepers use remineralizing products to get their water to the right GH
for the shrimp. Marine keepers do the same, but of course, use salt and may use calcium as well.
You might want to invest in a TDS
meter. It measures total dissolved solids in water, minerals, organics, whatever is solid, it tells you, giving a numerical reading. Often used by reef, marine and shrimp keepers, it can be quite helpful.
People do mix R0 and tap to get a balance, but if that is not working, you need a remineralizing product made for this purpose. I don't do it myself, I chose to keep fish that could handle the tap water, which is pretty hard and alkaline here too, maybe not quite as much as yours. It's near 8 when it first comes out of the tap.
Btw, do you actually have notes on the water you used to have ? KH
levels, as well as pH ? Minerals in water, notably calcium, help keep pH stable, they 'buffer' the water. Hard water is much easier to keep a stable pH in than soft water is, because the calcium and other hard minerals provide buffering. Very soft water has little buffering ability, so pH swings happen easily, but you already know that. I tend to type as if I am thinking out loud, sorry.
Water chemistry is a very complex topic, and I am still learning myself. I've managed to wrap my brain around the basics, but one reason I stick with tap is to avoid the issues you are facing now.
Seachem flourish Trace, or Trace elements is for plants.. trace mineral supplement for plants only. If ordinary ferts are not enough for the plants you keep, you may need trace nutrients too.
Often people get an iron test kit and measure for iron, because if iron is ok, usually, other trace minerals are too. You may wish to check Tom Barr's site, he is a bit of a guru on planted tanks, and there is a lot of info on various methods of dosing ferts. EI, or PP something, that I can't recall just this instant
I'll see if I can find a product name for you.
Link to a thread on Planted tank forum discussing various remineralizers and what folk think of them.
You really need to know what your old water was like, to have much hope of of getting close to it. Because you kept it below 7, acidic, it will be a bit harder to manage. How big is your tank, because these remineralizing things can get costly if it's any size.
What fish do you keep ?