Fish Tank Substrate Types Guide: 8 Materials Compared
Substrate is one of the few decisions that locks in the next two years of your tank — change your mind later and you are tearing the whole thing down. Yet most beginners pick whatever bag is cheapest at the shop and discover six months in that their plants melt, their corydoras shred their barbels, or their pH refuses to settle. This guide to fish tank substrate types from Gensou Aquascaping at 5 Everton Park compares eight common materials side by side so you choose once and choose correctly.
1. Standard Aquarium Gravel
Sized 3-5 mm, neutral in pH, and the cheapest option per kilo. Gravel works for community tanks with mid-water fish that never touch the floor. Detritus falls between the grains and gets siphoned out weekly. The downside is that bottom-dwelling species — corydoras, kuhli loaches, geophagus cichlids — abrade their barbels on the sharp edges. Inspect any gravel from the decoration and substrate range by running it between your fingers; if it feels rough, skip it for sand-loving fish.
2. Aquasoil for Planted Tanks
Baked clay granules pre-loaded with macronutrients — ADA Amazonia, Tropica Aquarium Soil, Fluval Stratum. Aquasoil drops the pH 0.5-1.0 units, holds 3 dKH down to 1, and feeds plant roots for 12-18 months without supplementation. It is the gold standard for stem plants, Buce, and shrimp tanks targeting soft acidic water. The catch is the ammonia spike during the first three weeks of cycling and the SGD 60-100 per 9-litre bag price tag. Stock from the substrate systems range.
3. Pool Filter Sand
Round-grained silica sand, 0.4-0.8 mm, pH-neutral and inert. Pool filter sand suits any tank that houses sand-sifters — corydoras, kuhli loaches, eartheaters — because the rounded grains protect barbels and gills. It is dense enough that detritus stays on top for easy siphoning, unlike the powdery play sand often confused with it. Singapore-bound buyers can find pool sand at Reef Depot or hardware shops in 25 kg bags for about SGD 30.
4. Black Diamond Blasting Sand
Crushed coal slag used in industrial sandblasting, jet black, very inert. Aquarists co-opted it because nothing matches the contrast it provides for colourful fish — German blue rams, apistogramma, neon tetras pop against the dark background. Rinse heavily before use; black dust takes a dozen passes through a bucket to clear. Not in mainstream aquarium shops but available on Carousell at SGD 10-15 for 20 kg.
5. Aragonite and Coral Sand
Calcium carbonate sand for African cichlids, brackish tanks and marine setups. Aragonite buffers pH to 8.0-8.4 and lifts dKH 4-6 points without separate dosing — exactly what Lake Malawi mbuna and Tanganyikans need. Never use it in soft-water tanks or planted aquariums; the buffering will lock pH above 7.5 permanently. Browse aragonite options in the substrate sub-category.
6. Bare Bottom
No substrate at all — just the glass floor. Bare bottom suits breeders, hospital tanks, discus growout setups and arowana keepers who siphon daily. Detritus is visible the second it hits the floor, water changes are faster, and ammonia never hides under the gravel. The aesthetic is industrial, but for productivity it is unmatched. A black acrylic sheet under the tank gives bare-bottom setups visual depth without compromising the maintenance advantage.
7. Inert Substrate Mixes
Seachem Flourite, CaribSea Eco-Complete, ADA Power Sand layered under inert grains. These provide cation exchange capacity for plant roots without the ammonia spike of full aquasoil. They are pH-neutral, last indefinitely, and let you avoid the cycle-from-scratch reset that aquasoil eventually demands. Better suited to root-feeders like swords and cryptocoryne than to stem plants. Available through the substrate systems listings.
8. Soil-Capped Setups (Walstad Style)
Organic potting soil under a 3 cm cap of inert sand or gravel — the Diana Walstad method. Soil provides nutrients and trace elements; the cap stops it leaching into the water column. Cheap at SGD 10-15 for enough soil to do a 60-litre tank, but the cycle is messy and tannins stain the water for months. A specialist approach — rewarding when it works, frustrating during the first six weeks.
Choosing by Tank Goal
Match substrate to your priority. High-tech planted tank with stems and shrimp picks aquasoil. Community tank with corydoras picks pool filter sand. African cichlid tank picks aragonite. Discus or arowana grow-out picks bare bottom. Low-maintenance display with tetras picks neutral gravel. There is no universal best substrate — only the best one for what you actually want to keep.
Singapore Sourcing Notes
Iwarna stocks ADA, Tropica and Fluval branded substrates. C328 and Reef Depot carry pool sand and inert gravel by weight. Petopia handles the smaller premium bags. Shopee and Lazada sell Eco-Complete and CaribSea but watch for fake repackaging — buy from sellers with verified import histories. Browse the full decoration and substrate selection for current local stock.
Related Reading
emilynakatani
Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
