ok heres my deal, i thought my sniffer that a bought was fuct so i got another , and it read the same that it was 3300 - 3500 in the house, however when i took it outside i saw a good reading of around 525-650 , so ive derived from there that it is not the sniffers, so ive shut off all gas appliences in the basement to see if thats why its so high?, just waiting for a few tolet it air out? , if anyone has had similar expeirience or has any advice it would be much appretiated..