Ive been trying to think up an inexpensive way to add a water chiller to my system that is in the works. Its a 4 5gal bucket setup with a 10gal rubbermaid as my res/control (holds 7 gallons when system is full). The entire system holds 21 gallons. I have drawn up a crap sketch to try and give you an idea of what I'm thinking. I am stuck on what I should put in the net pot, any ideas would be awesome. I was thinking maybe a sponge/s, gravel, a metal to retain the cool temp and chill the water. I plan on running the pump at max so it should send my entire system through the net pot 3 times an hour. Basicly the idea is to have 2 tubberware 1gal buckets, one with the lid. I will cut a hole to fit my 4in ABS Male/Female through the tubberware and the lid to my res. I will then attach the first tubberware bucket to the res lid with the 4in ABS Male/Female fittings. I will then cut a hole through the lid of the tubberware buckets to fit the 4in inline fan. I will seal the fan in the lid with 100% silicon sealent. I will then attach some 4in ducting to the 4in ABS coming through the bottom of the first tubberware bucket. I will then attach the other end of the ducting to the inline fan and then attach the lid to the first bucket. I will then add the second tubberware bucket upside down on top of the first bucket. Mind you that bucket 2 will not have a lid. Both buckets will be previously made light tight with foil tape. I will also have previously added copper tubes on the back side of the 2nd bucket to act as the air intakes. The tubes will sit about halfway into the bucket. I will create a slot on the bottom of bucket number 2( which is actually the top of the unit) that will allow me to slip a freezer Ice Pack in and out as needed. The ice pack will sit snug inbetween the two sets of copper tube stacks. So the idea really is to create air intakes that will adopt the temp of the ice packs cooling the air as it moves into the unit. Then pushing the cooled air through the net pot which will have the water recirculating through it. This should not only give me direct contact with the chilled air to my system water in small doses, but will also drop the air temp of the entire res which should also help cool the res water. If I'm going off the deep end here let me know. Just seems like it might work.