Rather than mess with water, I think I've got another idea which won't cost more than, say, $40 bucks. Get the cooler describe in the OP, and order four mini-keg ice blankets at about $5 each from Midwest Supplies.

http://www.midwestsupplies.com/5-liter-keglove-ice-blanket.html

I just ordered one of these to go inside my Pig Pen, which is an insulted sleve for my new Party Pig.

Seems to me that one of these ice blankets under the Mr Beer fermenter and one dropped over the top would do nicely. Leave the other two in the freezer- swap twice daily.

Whoa, no way. I just moved from Carrollton, and I spent a lot of time in Bremen. Small (internet) world.

A couple weeks ago, I was at Target and they were selling these large rubber "tub" type containers with handles for $6. I have been using this to control my temps on my fermenting bucket. There is no lid or anything, but I have it filled with water equal to the fill line on my fermenter, and twice a day, I swap out about 4 frozen 1 pint water bottles.

I wasn't sure how well it has been working, so I came home on my lunch break today to check on it. Holding steady at 57 degrees, over 5 hours after I left it! Mind you, this is in Louisiana and my house NEVER gets below 70. Needless to say, I was pretty excited that this has worked so well.

Douglas, with my rope tub bucket swamp coolers I normally put 2ea 16 oz
frozen bottles in twice daily during the first 3-5 days depending
on how quick the yeast works and then let it ride for a couple
weeks. Usually by then I have brewed more so I pull the buckets
out and set them on a towel for another week until I keg or bottle.
I dont know how it does it but the water stays 5+ degrees cooler
than the house at all times. Like a swimming pool sorta I guess.
It's actually difficult to move the temps in the swamp as it tends
to stay about 63* winter and 68* summer.
It also more closely duplicates how commercial breweries control
their fermenting temps with the coolant moving through the inner
liner of those big stainless tanks.
I also keep my rope tubs wrapped with blankets/ sleeping bags
for insulation.

thats alot of work.. and would like to point out its not working, you are working it... quite well actually but lots of work anyway... my insulated cooler(with a lid yes) will maintain 50's for days without all that work or potential mess... i know yours is cheaper but i have other uses for my cooler so that helps with the cost

Coolers are more ideal yes but one that will hold a 6.5 gallon
bucket fermenters would be pretty expensive if you could find
one. Some folks cut a big hole or fashion a new lid out of foam
so that an ordinary size cooler would work. Some folks even
use a bathtub.

oops, didnt catch that bucket part of it... back to the dictionary for me! yea finding a cooler to fit a bucket... not happening

It's not really lots of work. In the morning before I leave for work, I replace bring an armful of ice bottles and put the melted ones back in the freezer. At night when I get home, I do it again. Takes less than a minute each time, and cools a 6.5 gallon fermenting bucket in the Louisiana heat. In fact, it almost works TOO well, as my fermentation temps might be lower than they need to be. I'll probably try using only 2 or 3 bottles next time to see if I can keep temps in the low 60's.

I also have the $20 swamp cooler from Target, and use it for my Mr. Beer fermenter. Works like a charm, and is even easier than the bucket cooler. I was just surprised at how well the bucket works, considering that it isn't insulated or anything.

I just started using a swamp cooler. The one i had on hand was smaller than a 48 qt (not sure what size exactly maybe 32 qt). I had a bit of difficulty keeping temps with ice cubes. Then I hit on using the Mr Beer qt PET bottles. Fill with water and freeze. I use one at a time and i have been able to keep 52 consistantly. And this is in a Very Warm apartment (i have no heat control).

Thanks for posting this HJ.

BeerHead must be still reading the dictionary, have not seen him
around lately?

Glad it's working out for you Schrodinger Cat, I still ferment
99% of my batches in a swamp.