Who Gives A Fish Forums

I'm setting up a 75-gallon tank for Discus and need a reliable heater. Current temp fluctuates between 78-82F, which isn't ideal. What's your go-to heater for stability? Using a Fluval E300 now, but it's inconsistent.

I swear by the Eheim Jager 150W for my 55-gallon. It keeps temps within 0.5F of 84F, which is perfect for Discus. Pair it with an Inkbird controller for extra safety. How often are you doing water changes? That can affect stability too.

Fluval E300 is sketchy for Discus, IMO. Had one fail on me last year. Switched to a Cobalt Neo-Therm 200W, and it's been rock-solid. Also, check your tank placement—drafts mess with temps more than people realize.

turret wrote: ↑Fri May 02, 2025 1:02 pm Fluval E300 is sketchy for Discus, IMO. Had one fail on me last year. Switched to a Cobalt Neo-Therm 200W, and it's been rock-solid. Also, check your tank placement—drafts mess with temps more than people realize.

Second the Neo-Therm. Mine's running 24/7 in a 90-gallon with zero issues. What's your room temp like? If it's below 70F, you might need two heaters.

Ain't no way I'd trust a single heater in a big tank. Run two 100W Eheims at opposite ends. Redundancy cuts the risk of a crash. Also, y'all calibrate your heaters? Most are off by a degree or two outta the box.

Room temp's 68F here, and my Discus are chill with two Aqueon Pro 150Ws. Key is to match heater wattage to tank size—rule of thumb is 5W per gallon. OP, you're underpowered with a single 300W in 75 gallons.

Thanks for the tips. Gonna grab a second heater and an Inkbird. Room temp stays around 72F, but the Fluval's swings are stressing my fish. Appreciate the specifics on wattage too.

TankWarrior wrote: ↑Fri May 02, 2025 3:34 pm Ain't no way I'd trust a single heater in a big tank. Run two 100W Eheims at opposite ends. Redundancy cuts the risk of a crash. Also, y'all calibrate your heaters? Most are off by a degree or two outta the box.

This. Also, don't cheap out—budget heaters fail faster. My BRS titanium heater's lasted 4 years with weekly 50% water changes.

Anyone tried the Hygger quartz glass heaters? Heard they're decent for the price. My 40-gallon's at 83F steady with one, but Discus might need more precision.

My LFS swears by the Finnex Titanium for big tanks. Never used it myself, but their Discus are always vibrant. OP, how old are your fish? Juveniles need tighter temp control than adults.