Cobalt Neo-Therm 75W Submersible Heater fit check
Cobalt Neo-Therm 75W Submersible Heater is a 75W thin-profile heater. ReefCrafter's 2.5-5 watts-per-gallon band puts it at roughly 15-30 gallons of display water, before room temperature and redundancy choices. Pair it with a controller if a stuck-on failure would be hard to catch quickly.
Cobalt Neo-Therm 75W Submersible Heater: fits roughly 10-25 gallon systems. Specs, compatibility math, sizing risks, and alternatives before you buy.

Who it is for
Good fit for
- ✓ 10-25 gallon systems, per the catalog fit range.
- ✓ Roughly 15-30 gallons of display water at 2.5-5 W per gallon.
Not a fit for
- ✕ Tanks under about 10 gallons; it is sized above them.
- ✕ Systems over about 25 gallons without adding capacity elsewhere.
Listed features
- submersible
- thin profile
- shatterproof
- preset thermostat
- LED
Compatibility math
Safe wattage band
Example: 75W is usually a planning fit for roughly 15-30 gallons before room-temperature and redundancy choices.
ReefCrafter checks both the low-wattage failure and the oversized stuck-on failure.
Risk notes
- A single oversized heater can cook livestock faster than a beginner notices the problem.
Professional fit context
- Check wattage, controller, redundancy, tank size, and whether two smaller heaters are safer.
- Cobalt Neo-Therm 75W Submersible Heater fits roughly 10-25 gallon systems; confirm that range against the final display volume, sump volume, and livestock plan.
Alternatives to compare
- Eheim Jager TruTemp 75W Aquarium Heater
Same 75 W; compare format and features instead.
- Cobalt Neo-Therm 100W Submersible Heater
100 W vs 75: more heat for larger or colder tanks.
- Eheim Jager TruTemp 100W Aquarium Heater
100 W vs 75: more heat for larger or colder tanks.
Full spec snapshot
- Category
- Heaters
- Build tier
- Budget
- Estimated price
- $55
- Tank fit range
- fits roughly 10-25 gallon systems
- Format
- Thin Profile Heater
- Heater wattage
- 75 W
Related reading
Questions
What size tank is a 75W heater like the Cobalt Neo-Therm 75W Submersible Heater for?
ReefCrafter's 2.5-5 W per gallon band puts 75W at about 15-30 gallons. Cold rooms push toward the smaller end; tanks over 50 gallons are safer with two smaller heaters.
What tank size is the Cobalt Neo-Therm 75W Submersible Heater for?
ReefCrafter's catalog fit range for it is 10-25 gallon systems. Confirm that against your final display volume, sump volume, and livestock plan rather than the box label alone.
What should I compare the Cobalt Neo-Therm 75W Submersible Heater against?
Eheim Jager TruTemp 75W Aquarium Heater (Same 75 W; compare format and features instead); Cobalt Neo-Therm 100W Submersible Heater (100 W vs 75: more heat for larger or colder tanks); Eheim Jager TruTemp 100W Aquarium Heater (100 W vs 75: more heat for larger or colder tanks).



