6g New Nano Reef; Water Param Qs!

Hey all.

New to the site - been lurking for a little bit now but thought it's time to join! :banana:

My girlfriend and I have recently set up a 6g nano reef tank. This is our first saltwater aquarium after a few successful tropical freshwater tanks in the past. (Though we only have ever really needed to monitor PH)

We have had the tank running for about 5/6 weeks now, to cycle the tank - only adding corals & a clean up crew yesterday.

We have had a sandbed and about 2kg of live rock since day one.
We just added:
- 2x Mushrooms
- 1x Torch
- 1x Helio
- 2x Peppermint Shrimp
- 2x Turbo Snails
- 1x Narcissus Snail

Water testing this evening gave us the following results:
PH: 8.4
Ammonia: 0
Nitrite: 0
Nitrate: 0
Phosphate: 0/0.025
Specific Gravity: 1.022
Ca: 520
KH: 10

I should mention that we are very new to testing water, and I have reservations that we have done it correctly. We will take some water into a store to get it tested when we can.

Our concerns are that the water is too hard, and that the Calcium is too high.

Firstly regarding the hardness, I have read that adding RO water is one way to soften the water? I have found it interesting that since starting the aquarium we have tested the SG prior to adding any water (only adding to top up from evaporation not WC yet), and it has been 1.022 so we haven't added RO water yet (as this would lower the SG?)

I thought maybe our Ca was high as we have only had coral in there since yesterday.

I also found it weird that we didn't have any nitrate.

What would you be doing in our position?

Thanks!
Bob and Jon. :wavey: