# Interpet Deltatherm Aquarium Fish Tank Heater, adjustable, for Tropical and Marine, 300 W, for aquariums up to 270 litres, Black

Source: https://www.ranked10.co.uk/pet-supplies/best-aquarium-heater/interpet-deltatherm-300w
Ranked #1 in "Best Aquarium Heater 2026: Ten Ranked on Real Watts per Litre": https://www.ranked10.co.uk/pet-supplies/best-aquarium-heater

- Price: £19.99 (checked on Amazon UK on 2026-09-08)
- Amazon rating: 4.5 from 1,243 ratings
- Buy on Amazon: https://www.amazon.co.uk/dp/B003VZFP6K?tag=ranked10-21

The Interpet Deltatherm 300 W is our number one aquarium heater pick for September 2026. It is a double insulated, fully submersible heater for tanks from 135 to 270 litres, with positive click temperature control. The listing records 1,243 ratings at 4.5.

Everything on this page comes from the Amazon listing rather than our own testing.

## Specification

| Field | Value |
|---|---|
| Watts | 300 W |
| Tank size | 135-270 litres |
| Range | 16-34 degrees |
| Glass | Heat and shock resistant, double insulated |
| Dimensions | 35.5 x 2.5 x 2.5 cm |
| Preset | 24 degrees |
| ASIN | B003VZFP6K |

## Questions people ask

**What size tank is it for?**

Aquariums from 135 to 270 litres.

**Is it adjustable?**

Yes, with a positive click control from 16 to 34 degrees.

**Does it suit marine tanks?**

Yes, it is rated for tropical freshwater and marine.

**What temperature does it ship at?**

Set to 24 degrees.

**Is it submersible?**

Yes, fully submersible and double insulated.

**What is the rating?**

4.5 across 1,243 reviews.