Alternative heater - Trojan Hot Scot found here

The Brower 77Assy Space heaters is intended to be used under the metal MK30, MK32 and MJ31 automatic waterers. Made of heavy-gage steel with baked on enamel finish, the 77assy includes an adjustable thermostat.

The 77Assy can also be used under metal buckets and various enclosures.

Each box includes:

1 - 77 Space Heater

1 - MK315 Junction Box Stand-off Bracket

2 - OF58 5/16-18 X 9/16 X 7/32 Hex Machine Nut, Brass

1 - ISH77ASSY Instruction Sheet 1

NOTE: MH30 takes two 77ASSY - 77 Assembly Heaters. MJ31, MK32 require only one.

INSTRUCTIONS

1. Remove the access door by turning the 2-1/4 Turn SS Studs (push in and twist counterclockwise). Discontinue electrical service to any existing electric unit.

2. Inside the waterer on the underneath side of the trough, locate the center bolt that is welded to the bottom of the trough and protruding downwardly.

3. Place bracket on this center bolt and tighten with one of the brass nuts.

4. Place the heater on the bolt that is welded to the bottom of the bracket. Attach the heater to the bracket by placing the pre-drilled hole in the middle of heater on the bracket bolt. MAKE SURE THE HEATING ELEMENT OF THE HEATER IS FACING UP AND THAT THE POWER CORD IS ON THE LEFT SIDE AS THE HEATER IS MOUNTED. Turn the electric unit at an angle as much as possible(and still allow the access door to be replaced) so that you see and access the control knob. Tighten heater to the bottom of the bracket using the second brass nut.

5. Plug in power cord.