Water quality question for new tank

[RCDV]

Hello everybody,

A little bit of context before my question.. Im waiting delivery of my new 320 gallon tank next week and the problem is tap water here has lots of minerals. I measured the TDS and it has 616 ppm. In my 55 gallon tank I stopped using tap water because I was getting a nasty calcium crust above the water level and I started using drinking water which has 140ppm. I can afford to do this on my 55 but not on the 320 im waiting. I ordered a RO system to fill it out but im reading that its bad to add RO water only, that it should be mixed with tap water beacuse fish need some minerals. Is this true or can I use RO water only? If not, what percentage of each should I mix in order to have my tank's glass free of crust? And how low can the TDS be to be safe for fish?

Thank you very much!

 

[RCDV]

Just ordered Seachem Replenish. It is supposed to be for RO water. Has anyone used it? Any tips for dosage besides the ones on the label?

 

[duanes]

I also have heavily mineralized tap water, and always have.
The solution for me, was to acquire fish from that type water in nature, and there are plenty, so no need to fight it.
I found I could always keep Central American, Mexican And Caribbean fish,
they always did really well in that kind of water, and lived without disease problems.


I also found in that water African rift Lake species did well.

There are also plant species that do best in that water, although some don't.
Research is the key

Because........

When I tried to keep South American Amazonian soft water species, it always turned out to be a losing battle, with diseases like HITH.
.