About 20 years ago I had two Supreme heaters in a 55 gallon tank with about 100 African Ciclids. During a weekend trip both contacts in the heaters fused and I came home to about 55 gallons of opaque fish soup (very messy). I replaced the heater with a solid state one and had no problem until the Oscar grew to about 13 inches and smashed the tube creating a loud pop. Being in Amateur Radio I was familiar with OP amps and a thermisistor available through Radio Shack for a couple of dollars. I believe I had it trigger a larger relay and had a hysteresis circuit with the OP amps so it would go on at one temp and off about a degree higher. I must have used it for quite a few years in NJ in a room that got pretty drafty. I forgot about it as I was traveling a lot and my wife sold the tank and contents for me when we decided to sell the house and move. I would think a solid state thermostat including a solid state relay would be the best way to go (no physical relays or contacts or bimetallic strip). The parts themselves are very inexpensive if you were going to make it yourself and were good with electronics. Below is a reference to a FAQ at The Krib for a very high quality heater for $65. I don't know how old the reference is, but on Google I found many references to solid state heaters. http://www.thekrib.com/TankHardware/heaters.html Steve P. ------------------ To unsubscribe from this list, please send mail to majordomo@thekrib.com with "Unsubscribe aga-member" in the body of the message. Archives of this list can be found at http://lists.thekrib.com/aga-member/