What the Nano 3.5 Gal Marine Aquarium Starter Kit actually includes

The Nano 3.5 Gal Marine Aquarium Starter Kit from Castle Dawn Aquatics is an all-in-one desktop marine system. It bundles the tank, a full-spectrum marine LED spotlight, a water pump, a protein skimmer, and filter media, so you are not hunting for each component separately. The built-in wet and dry filtration chamber and skimmer are designed to save space and keep wires hidden.

The kit is available in three sizes: HG15 (4 litres, about 1.06 US gallons), HG20 (7 litres, about 1.85 US gallons), and HG25 (13 litres, about 3.43 US gallons). The '3.5 Gal' name refers to the largest HG25 model. If you want the exact capacity in the title, choose HG25; the smaller models hold noticeably less water.

Dimensions and glass thickness by model

  • Nano 3.5 Gal Marine Aquarium Complete Starter Kit: HG15: 15 × 15 × 20 cm (H × L × W), 4 litres, 4 mm glass; HG20: 20 × 20 × 20 cm, 7 litres, 4 mm glass; HG25: 25 × 25 × 25 cm, 13 litres, 5 mm glass. Footprint and glass thickness affect where the tank fits and how sturdy it feels. The HG25 is the only model with 5 mm glass and the full 3.43 US gallons.

    Nano 3.5 Gal Marine Aquarium Complete Starter Kit

    Nano 3.5 Gal Marine Aquarium Complete Starter Kit

  • Nano 3.5 Gal Marine Aquarium Complete Starter Kit: Pump chamber width is 5.5 cm for all models. Water pump power: 3 W for HG15 and HG20, 5 W for HG25. LED marine spotlight power: 11 W for all models. The fixed pump chamber width means equipment space is the same across sizes, while the larger HG25 uses a stronger pump for its greater water volume.

The real trade-off: small water volume means closer attention

A nano marine tank is compact, but that compactness cuts both ways. The manufacturer notes that you should always keep a closer eye on salinity, temperature, and water parameters when keeping marine species in nano aquariums. Smaller volumes shift faster, so a nano reef tank kit rewards consistent testing and topping off rather than a set-and-forget approach.

The kit is described as suitable for marine and freshwater nano setups, and for reef use you must cycle the tank properly before adding livestock. It is listed as ideal for soft corals, small frags, cleaner shrimp, snails, and nano reef setups. That gives you a realistic starting point: this is a small-saltwater-aquarium kit for a modest, carefully chosen community, not a system for large fish or a heavy fish load.

Delivery is another practical constraint. Due to the weight of these aquariums, they must travel via sea shipping, and the estimated delivery time is 35 days. Plan your purchase around that lead time rather than expecting a quick desktop arrival.

Which size fits your plan?

Use the model sizes to match the tank to your space and the livestock you have in mind. The HG15 and HG20 are true desktop footprints; the HG25 is still compact but gives you the 3.43 US gallons the product name implies.

  • HG15 (4 litres / 1.06 US gal): Smallest footprint at 15 × 15 × 20 cm. Best if desk space is tight and you want a very small soft-coral or shrimp-focused nano setup. Be aware that 4 litres leaves little margin for error in salinity and temperature.
  • HG20 (7 litres / 1.85 US gal): Middle size at 20 × 20 × 20 cm. A compromise between desk footprint and a bit more water volume than the HG15, though still well short of the 3.5-gallon title.
  • HG25 (13 litres / 3.43 US gal): The model that matches the 3.5 Gal name. At 25 × 25 × 25 cm with 5 mm glass and a 5 W pump, it offers the most water volume and stability of the three, while remaining a nano tank.

Setup and maintenance expectations

The all-in-one design includes a built-in wet and dry filtration chamber, a protein skimmer (DF46 on HG15 and HG20, DF51 on HG25), and quick-access chambers that make filter changes simple. The manufacturer states that the wet and dry filtration improves biological stability and increases oxygenation. For a saltwater aquarium kit beginner, that means fewer separate devices to buy and wire, but you still need to cycle the tank and monitor parameters before adding livestock.

The kit carries a 1-year warranty (terms and conditions apply). Beyond the supplied information, specific maintenance intervals, feeding amounts, and livestock stocking limits are not confirmed here, so base those decisions on your own testing and reliable marine references rather than assuming a fixed schedule.

Key kit facts at a glance

  • Nano 3.5 Gal Marine Aquarium Complete Starter Kit: Includes nano marine aquarium tank, full-spectrum marine LED spot light, water pump, protein skimmer, and filter media. Confirms it is a complete starter kit rather than a bare tank, which matters for first-time saltwater buyers comparing against pieced-together setups.
  • Nano 3.5 Gal Marine Aquarium Complete Starter Kit: Suitable for marine and freshwater nano setups; for reef use, cycle the tank properly before adding livestock. Sets a clear precondition for reef use and explains why this kit is not a same-day reef.
  • Nano 3.5 Gal Marine Aquarium Complete Starter Kit: Must travel via sea shipping; estimated delivery time is 35 days. A long lead time that should factor into your buying timeline.