So i recently had a situation where my room temp was spot-on but a new all-black propagator res had nute temps shooting into the high 80's-90's
I couldn't really quit my job to stay home and swap out frozen water bottles every 1.3 hours so I took my usual $20 spending cash to wally world and used other parts I had on hand to build a chiller for the res with less than $20.
The first thing you'll need is one of these coolers. compare prices at wally world. h.d., etc.
In addition to that sucker you'll need a sampling of 1/2" barb fittings, 1/2" tubing and nipples (tee hee). I had them laying around but they could be had new and still likely meet the $20 budget.
Shown above is some of what you'll need.
a 3'4 drill bit
Black aquarium silicone. Doesn't have to be be black, it's what I had.
FOUR 1/2" threaded to 1/2" barbed elbows. TOROs funny-pipe fittings work great.
TWO 1/2 threaded risers with the length being long enough for the thickness of your cooler.
10ft or more of 1/2" tubing
Hits from the treefrog pipe optional
First thing we need is and IN and and OUT as shown here. I put one at the very bottom and one at the top. take into consideration how deep the lid seats or you wont be able to close it
Drill your two holes with the 3/4" drillbit.
Here's a few detail shots showing the nipples snugly fitting through the holes inside and out.
I wasn't sure if I'd get a good seal on the outside texture with an o-ring so I used the silicone as a thread sealant. coated all the threads before assembling the elbows
The elbows finished inside. Notice the opposite directions. you're going to have a spiral of hose inside the cooler so one will need to face left, one right
Wind your length of 1/2" hose inside from bottom to top in a coil pushing against the cooler. 10ft is good, 20 ft would've been better.
Here's my interior after sealing the hose into place and a couple coats of white plastic spraypaint to give it the "fridge look" lol
This is powered by a small pump I have for draining res's. Any small pump is good. The idea is to let the nutes flow through the chiller as slow as possible, accelerating cooling. a small aquarium powerhead would work fine. The only time in hydro where smaller is OK lol
Just drop the pump into your res, connect to the top fitting. connect the bottom to drain back in your res, fill with ice and top of with cold water.
Obviously this works best away from the heat of your grow area. as long as there is no big uphill pumping you can put this outside your closet or in an insulated area.
If it starts chilling too much, just use more water/less ice.
Once a day maintenance and it works so much better than frozen bottles after every damn sitcom.