Doing Water Change- Need Help ASAP

[Jaws]

Thanks guys. I was moreso worried about the oily film on the top of the water. I haven't seen this before and though something might have got into the water and contaminated it. I added some alk and Ca buffer and did the water change anyways. I expected some corals to slime up and the skimmer to go nuts if there was a problem but everything seemed fine. Still nothing detectable the next morning but I'll keep an eye on it and post if I notice anything. Thanks for your help.