This is based on https://www.plantedtank.net/forums/di...=inline+heater
by Snazzy except that I used 2 inch PVC, and the input/output is 1 inch. Just make two of these and join the two bottom elbows together as shown. I will not go into detail on the construction. Just see Snazzy's design.
The heaters are two 150W Hydor units. The one on the right has the Heyco cord grip not installed.
Why two heaters? Well...
- They were cheap. I bought them at a clearance sale at 50% off.
- One was not enough. It can get down below 65 F here in the winter (inside temperature).
- Redundancy. If one quits there will still be the other one.
Actually, there will be a total of 3 heaters. The two 150 watts inline and a 75 watt substrate heater, for a total of 375 watts. However, the 150 watt units will be set to a temperature of 75 F and 77 F, and the substrate heater will be set to 79 F. In this way the heater power levels will be either 75, 225, or 375 watts---what ever is required at the time to maintain the tank at 79 F.