I placed this 50 watt heater in the hidden filter stage of my 3 gallon Marinland aquarium. It quickly provided a stable temperature of 75F for almost a week. That's exactly what I set it up for. Very happy with it (as was my fish).
Convector Electrolux ECH/T-2000 M, white
21 Review
π Fluval E300 Electronic Heater - 300W Advanced Aquarium Heater for Tanks up to 100 Gallons (A774)
9 Review
YukiHalu Mini Submersible Aquarium Heater With Thermometer And Temperature Controller - 25W, 50W, 100W, Or 200W Options For 5-40 Gallon Fish Tanks
25 Review
Sectional radiator Royal Thermo PianoForte 500, number of sections: 10, 11.7 m2, 1170 W, 800 mm.
31 Review
Vacuum cleaner TEQQO Aquastick 3 in 1 Power, grey/turquoise
26 Review
Mini pump Xiaomi Mijia Electric Pump 1S, plastic, black
55 Review
π U-BCOO Aquarium Gravel Cleaner Fish Tank: Manual Siphon for Efficient Filter Gravel Cleaning and Water Change in Tanks
22 Review
𧲠Efficient Magnetic Fish Tank Cleaner: KEDSUM Floating Clean Brush with Handle Design
34 Review