Hi All, I store my boat in the water under a shed in southern Virginia. I winterized the boat with non-toxic antifreeze. This winter I found mold in the toilet bowl and on the bilge water. I pour antifreeze in the bilge to run thru the bilge pumps. I did the same last winter & had no growth. The only thing different is last year I had a couple 150 watt light bulbs on in the engine room. I did not think it necessary to pay for electric at a flat rate to use so little amount, but could I be wrong? I don't think the heat they generated would help matters in the cabin head, where much mold was present. Any input would be appreciated. Gary