My water hardness with discus, help please.

Hi everyone, first post and was hoping I could get some help.

I keep tropical fish for a while now and now am taking the plunge with a discus tank. My question really relates to water hardness etc. The discus breeder I am getting my fish from has a gh of 3 and a ph of 6.5. My water has a gh of 13 ph of 8 and a kh of 8. Does anyone think I can get the discus to acclimatise to my harder water or should I be looking at mixing RO with my tap water? I don’t have the fish yet so can change parameters before they arrive but I have also read quite a few people saying discus will be ok in my water as long as I don’t want to breed. Do you think that would be the case?

Thanks in advance for your help.