If you are just trying to hide the heater, I have excellent luck with the AF92. They take any heater above a certain diameter. I think the smallest ones don't fit unless you get a bushing from the hardware store.
For your setup, I think inline heaters would be the way to go. You just need to make sure to get the ones that fit Fluval hosing. I just switched out my old Eheim with a Fluval and it was a PITA retrofitting couplings to join the two separate hose sizes to put the Fluval in line with the rest of the system
has anyone ever heard of the heating pads for under the tank? I was told this is out there but cant seem to find it anywhere? Anyone know if this is true and where to find them????
Do you mean that the heating pad goes underneath your tank between the tank and stand? A couple of things that bother me is that what if the heater malfunctions? You would have to empty the whole tank to fix it. Also, do they make heaters like that? I would think that the weight of the tank will break the heating pad. I would just go with an inline heater, use in sump, hide with sometype of decoration, or place the heater parallel with the gravel. Good luck, The Doctor.
Hydor Hydrokable Heating System-100 Watt Versatile substrate heater designed for use in aquariums and terrariums. Can be completely submerged or used dry in a reptile tank. In aquariums the warmed water creates a slow water circulation effect throughout the media, which is beneficial to live aquatic plants and other tank inhabitants. Includes suction cups for ease of placement. Reliable and easy to use! This model is recommended for aquariums 40-65 gallons in size. In the terrarium, the Hydrokable warms the entire substrate media to a desired temperature eliminating sections of uneven heating. For indoor use only. Reliable and easy to use.
I have two available that were used for around 5 months submerged beneath the gravel in a 220 gallon freashwater planted aquarium. I beleive that the heat provided to the roots of the plants attributes to some of the good success I have had witht he plants. When I set up another planted tank, I will be using these again. Thermostats or Rheostats can be used in combination with them if you are looking to acheive specific and precisely maintained temperatures however they work in their own right or in combination with other aquarium heaters. Each cable is 32.8' or just shy of 400". They are meant to be folded back and forth to cover a certain area.