Another way if you want to chill your shit nice and easy, maybe try this, I'm going to do it this summer if temps cause an issue in my rdwc. Its just taking a bit of brewing diy to work for this.
Equipment needed:
1. Stc1000 - temp controller unit
2. Old extension cords or new. Need one wall outlet socket and two power sockets.
3. Brewing heat pad
4. Freezer (big enough to fit your res)
All you need to do is buy a stc1000, cut up the extension cords to use the wire etc and wire up the stc1000.
Drill holes in side of freezer for lines from res to other buckets in the tent/room etc, seal around any gaps.
The freezer is plugged into the 'cooling' plug of the stc1000 and the heat pad into 'heat' plug on stc1000, temp the temp gauge just needs to be attached to the outside of the res, bit of bubble bag to insulate.
Then just dial in the temp you want the res ,to be and it will get you down to whatever you want