[new 390l temperate marine tank]

Have patience my son. Good things take time.

[Are there any fish keeper in the hawkes Bay Area on here ?]

I keep a tropical marine tank and live in Napier.

[What type of water for salt water?]

You may be thinking of a TDS meter which stands for total dissolved solids. Its a measure of how pure the water is.

They are only a few bucks on trade me etc.

[Saltwater Water Changes]

on internationals forums am I hit with a big no no

Less pollution in New Zealand. People have been doing this for years

as to do you still need to if Natural salt water contains the correct amount of calcium, magnesium etc. In my opinion yes you do because the corals take up those elements as they grow and they need replacing so in order to get the best growth you need to dose to replace those lost elements.

[Saltwater Water Changes]

Yes it is common and yes you can keep those fish.

Its very common in fact as salt is so expensive its a good option if its available to you.

As the others said just check and adjust the salinity and then its good to go.