How to Aquascape a 90cm Tank: Scaling Up Your Design

Why Move to a 90cm Tank
Key Differences From a 60cm Setup
Layout Styles That Work at 90cm
Hardscape Quantities
Substrate Plan
Planting Zones and Species
Equipment and Stocking
Budget Breakdown (SGD)
Frequently Asked Questions

Why Move to a 90cm Tank

The 90 cm tank (typically 90 x 45 x 45 cm, holding approximately 180 litres) is the natural upgrade once you have gained confidence with a smaller setup. The extra width and depth open up design possibilities that simply do not exist in a 60 cm format: more complex compositions, deeper substrate slopes and enough swimming space for a truly impressive school of fish.

For Singapore hobbyists in HDB flats and condos, a 90 cm tank remains practical. It fits on a standard aquarium cabinet without dominating the room, yet delivers the visual impact of a much larger setup. If you have not yet built a smaller layout, start with our guide on how to aquascape a 60cm tank first.

Key Differences From a 60cm Setup

Scaling up is not simply a matter of using more of everything. Several fundamentals change at 90 cm.

Factor	60cm Tank	90cm Tank
Volume	~60-65 litres	~180 litres
Substrate	2-3 kg	5-7 kg
Hardscape	3-5 kg	5-10 kg
Plant species	5-7	7-12
CO2 rate	~1 bubble/sec	~2-3 bubbles/sec
Water change	~20 litres (30%)	~55 litres (30%)
Total weight	~80-90 kg	~220-250 kg
Fish capacity	15-20 small	30-50 small
Budget (SGD)	$500-800	$1,000-2,000

The 45 cm front-to-back depth gives you 50 per cent more room for perspective tricks than a standard 30 cm-deep 60 cm tank. Hardscape must be scaled up too; stones that looked impressive at 60 cm may appear underwhelming at 90 cm. A filled 90 cm tank weighs 220 to 250 kg, so a purpose-built aquarium cabinet is essential.

Layout Styles That Work at 90cm

Every major layout style works at 90 cm, but each benefits from the larger canvas in different ways.

Triangular – The extra width allows a more gradual slope and genuine negative space on the open side.
Concave (U-shape) – The central valley can be wider and more dramatic, creating a powerful vanishing point. This is the most popular competition style at this size.
Island (convex) – A central mound surrounded by generous open space produces a floating landscape effect difficult to achieve in smaller tanks.
Multi-focal – Unique to larger tanks, a primary mass with a secondary accent grouping on the opposite side works naturally at 90 cm without visual competition.

For hardscape arrangement principles, see our hardscape layout guide.

Hardscape Quantities

Stone

Plan for 5 to 10 kg total:

1-2 hero stones (15-25 cm) as main focal pieces
2-4 medium stones (8-15 cm) for support
5-10 small stones (3-8 cm) for transitions and borders

Buy 20 to 30 per cent more than you think you need. Extra pieces let you try different arrangements during dry layout.

Wood

Select one main piece 40 to 60 cm long, supplemented with one or two accent pieces. Spiderwood and Manzanita are popular and widely available at Singapore aquascaping shops.

Substrate Plan

You need 5 to 7 kg of aquasoil plus 2 to 3 kg of pumice filler for building height at the back.

Position	Depth	Purpose
Front edge	3-4 cm	Thin for carpet, maximises visible glass
Mid-ground	5-8 cm	Rooting depth for mid-ground plants
Back corners	10-15 cm	Maximum height for dramatic slope

This slope from 3 cm at front to 12 to 15 cm at back creates a convincing illusion of distance across the 45 cm depth. If your design includes a sand path, allocate 1 to 3 kg of cosmetic sand such as ADA La Plata or JBL Sansibar White.

Planting Zones and Species

Divide the tank into foreground, midground and background zones. Use 7 to 12 species total, planted densely from day one to outcompete algae in Singapore’s warm water.

Zone	Species	Quantity
Foreground carpet	Monte Carlo, Eleocharis mini	4-6 tissue culture cups
Foreground accent	Cryptocoryne parva, Marsilea hirsuta	2-3 pots
Midground	Staurogyne repens, Bucephalandra	3-5 pots
Background (green)	Rotala rotundifolia, Hygrophila pinnatifida	4-6 bunches
Background (colour)	Ludwigia palustris Super Red, Rotala H’Ra	2-3 bunches
Epiphytes	Anubias nana Petite, Christmas moss	3-5 portions

Place red or coloured plants as concentrated accent points rather than scattering them. A cluster of Ludwigia Super Red at one side of the background creates a far stronger focal point than red stems distributed evenly across the tank.

Equipment and Stocking

Item	Recommendation	Cost (SGD)
Tank	90 x 45 x 45 cm rimless, 8-10 mm glass	$150-300
Cabinet	Purpose-built, rated 250+ kg	$150-400
Light	90 cm LED (Chihiros WRGB II, Twinstar 900S)	$150-450
Filter	Canister, 200-400 litres (Oase BioMaster 600)	$150-300
CO2	Pressurised, 3-5 kg cylinder	$150-250
Substrate	5-7 kg aquasoil + 2-3 kg pumice	$60-100
Hardscape	5-10 kg stone or driftwood	$60-200
Plants	7-12 species	$80-150
Tools	Long scissors, tweezers, conditioner, test kit	$60-120

Singapore-Specific Notes

A single large canister filter is preferable to two smaller ones for simplicity and consistent flow.
A 5 kg CO2 cylinder lasts three to four months at this size versus six to eight weeks for a 2 kg cylinder.
At 180 litres, temperature is more stable than in a 60-litre tank. A clip-on fan keeps water at 28 to 30 degrees Celsius during the hottest months.
Invest in a Python-style water changer for 55-litre water changes. Carrying buckets gets old quickly.

Sample Stocking Plan

20-25 cardinal tetras (main schooling fish)
5-6 Otocinclus (algae control)
10-15 Amano shrimp (clean-up crew)
8-10 Corydoras pygmaeus (bottom-dwellers)
3-5 Nerite snails (glass cleaning)

A school of 20 to 25 cardinal tetras in a well-planted 90 cm tank is one of the hobby’s most impressive sights. Add fish gradually over three to four weeks after cycling completes.

Budget Breakdown (SGD)

Category	Range (SGD)
Tank	$150-300
Cabinet	$150-400
Light	$150-450
Filter	$150-300
CO2 system	$150-250
Substrate and sand	$60-100
Hardscape	$60-200
Plants	$80-150
Tools and accessories	$60-120
Livestock	$50-100
Total	$1,060-2,370

Most setups land comfortably in the $1,000 to $2,000 range. The cost jump from 60 cm is not proportional to the size increase. Substrate and plants roughly double, but the tank, filter, light and CO2 are only modestly more expensive. The biggest new line item is the cabinet, essential at this size but optional for a 60 cm on a desk.

Frequently Asked Questions

Can I place a 90cm tank on the second floor of my HDB flat?

Yes. HDB concrete floors are designed for significant loads, and 220 to 250 kg is well within capacity. Position the tank against a wall, use a cabinet that distributes weight evenly, and avoid placing it in the centre of a span. If your flat is older and you are concerned, consult an HDB-approved contractor.

Is a 90cm tank much harder to maintain than a 60cm?

It takes longer but is not more difficult. Budget 60 to 90 minutes per week versus 30 to 45 for a 60 cm. The main change is water change volume (55 litres versus 20). Water parameters are actually more stable in the larger volume, making the tank more forgiving of small mistakes.

Should I use one light or two?

A single 90 cm LED provides the most even coverage without overlapping bright spots. Chihiros, Twinstar and ONF all offer dedicated 90 cm models. If reusing a shorter light from a previous setup, supplement with a matching unit of the same model and colour temperature.

Scale Up With Gensou

Moving from 60 cm to 90 cm is one of the most rewarding upgrades in the hobby. At Gensou Aquascaping, we have over 20 years of experience designing large-format layouts for Singapore homes and offices. Visit us at 5 Everton Park, explore our aquascaping services, or get in touch to plan your 90 cm masterpiece.

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How to Aquascape a 90cm Tank: Scaling Up Your Design

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