I have had a RIS sitting in secondary for 4 months now with plans to bottle around October to drink at Christmas time. Tonight I was checking on the airlock and noticed it was very low. I added some unsanitized tap water to the airlock but the cap piece that floats off of the stem was stuck to the bottom of the airlock water tube. When I tried to use my finger to dislodge the cap I heard the distinct sound of water (unsanitized, and some of it sitting for 4 months gathering dust and nasties) draining into my beer. If this was an ordinary batch I would just bottle and not worry about it, but I have a lot of time and high hopes invested in this batch. I have some campden tablets sitting around and I am considering adding 5 crushed tablets to the 5 gallon batch, then letting it continue to age until October, add some champagne yeast 2 days before bottling, and procede with the bottling. First, I would like to know if this should keep the batch from getting infected, and secondly would it effect the taste of the finished product to use campden tablets in beer? If anyone has experience with this please let me know what is best to do. Thanks.