Years ago, when I was immersed in fish keeping, I had my heater placed in my 29 gallon tank vertical with the control above the water line. I am guessing this is incorrect. I currently see most if not all, placed on an angle totally submerged. Is this the correct acceptable method? Thank you and I have a 29 gal tank with the HOB filter on the back right corner. Again, thank you
Steve
Steve