[i have a 30g tank with just live rock. My calcium level is 540 is this bad? should i just do a water change? I have no animals in the tank it's been running for 3 days. How long should I wait to add corals? :Oo:] said:[If the tank is just set up with no corals, just keep the tank buffered. I think the alkalinty needs to be a little higher aound 10dkh and you will start to see the calcium level drop. I bet you are using Oceanic salt? If you start keeping corals in the tank and you still have the calcium that high, you will have problems. Unless you really buffer the tank to keep the alkalinty up and keep your magnesium at a really elevated level at 1500. The calcium would be at a better level around 400.]