as hot as it has been in Georgia lately, I have been using a 50 ft immersion chiller plus a 25 foot prechiller. I don't ice down the prechiller until the wort is below 100. My tap water the other night was 78 degrees.
edit: I should have said I guess it depends on how cold your tap water is. My 25 foot worked ok in the winter time when the tap water was below maybe 50 degrees (don't remember)
Carport Brewery, Lilburn GA
Any advise offered after 10:00p.m. should be regarded as questionable
I can't brew until something is empty
Reason: added on