water changes adding minerals that need Replenishing

[aquaherper]

I have a 30 g heavy planted low light setup.
15 or so fish
I add liquid co2 and an iron sup.
I do my water changes with water from a 5 stage filter which filters down to a Nuclear level or what ever.
So I'm not replenishing anything pretty much when I do a water change. Do I need to be adding more minerals With my water changes?

 

[Rivercats]

If you Gh and Kh are both 4 or above you don't need to worry about replenishing minerals.

 

[aqua_chem]

Does your water filtration system include something to soften the water? You may run into problems if it does.

 

[aquaherper]

Not sure.