Aquarium Water Parameter Cheat Sheet: Ideal Ranges for Every Setup

Water parameters underpin every decision in the aquarium hobby — stocking choices, fertilisation, equipment selection, and troubleshooting all depend on knowing what your water contains and what your animals require. Yet many hobbyists only test when something goes wrong. This aquarium water parameter cheat sheet from Gensou Aquascaping at 5 Everton Park, Singapore consolidates the ideal ranges for the most common aquarium types into one practical reference, with notes on Singapore’s specific tap water conditions.

Singapore Tap Water: Your Baseline

PUB tap water in Singapore is soft and slightly acidic after dechlorination: pH typically 7.0–7.4, general hardness (GH) 2–4 dGH, carbonate hardness (KH) 1–3 dKH, and TDS around 90–130 ppm. It is chloramine-treated, not free-chlorine treated — this means standard sodium thiosulphate dechlorinators are insufficient. Use a product that explicitly neutralises chloramine, such as Seachem Prime. This baseline makes Singapore tap water naturally suitable for soft-water species but requires remineralisation for hard-water fish and shrimp.

Community Freshwater Tank (Mixed Tropical)

For a general community tank with tetras, livebearers, corydoras, and similar species, aim for pH 6.8–7.5, GH 6–12 dGH, KH 3–6 dKH, temperature 24–27°C, ammonia 0, nitrite 0, and nitrate below 20 mg/L. These ranges accommodate the widest variety of commonly kept fish. TDS between 150–300 ppm is appropriate.

Livebearers — guppies, mollies, swordtails — prefer the harder, higher-pH end of this range. Add a small amount of crushed coral or aragonite to the filter media to gently buffer pH and raise KH if you keep mollies in particular, which are highly sensitive to acidic conditions.

Planted High-Tech Tank

With CO₂ injection and fertilisation, parameters shift: pH 6.5–7.0 (CO₂ drives pH down during the photoperiod), KH 2–4 dKH (low enough that CO₂ achieves meaningful pH depression), temperature 23–26°C. Ammonia and nitrite remain zero. Nitrate: 10–25 mg/L (a positive level supports plant growth). Phosphate: 0.5–2 mg/L. Potassium: 5–15 mg/L. Iron: 0.1–0.5 mg/L.

Test CO₂ indirectly via the pH/KH drop table or use a drop checker. At KH 4, a pH drop from 7.4 (without CO₂) to 6.8 (with CO₂ running) indicates approximately 30 mg/L dissolved CO₂ — a safe and effective level for plants. Never let pH drop below 6.2 with fish present.

Neocaridina Shrimp Tank (Cherry, Yellow, Blue Velvet)

pH 7.0–7.6, GH 6–8 dGH, KH 2–4 dKH, TDS 150–250 ppm, temperature 22–26°C, ammonia 0, nitrite 0, nitrate below 10 mg/L. Neocaridina shrimp are tolerant of Singapore tap water with minimal adjustment — often just dechlorination and partial remineralisation is sufficient. Avoid copper in all forms; it is acutely toxic to invertebrates.

Caridina Shrimp Tank (Crystal Red, Taiwan Bee, Tiger)

Caridina shrimp require significantly softer, more acidic water: pH 5.8–6.8, GH 3–5 dGH, KH 0–1 dKH, TDS 100–160 ppm, temperature 22–25°C. These parameters cannot be achieved with Singapore tap water alone — remineralisation of RO water using a Caridina-specific GH+ mineral supplement (such as Salty Shrimp GH+) is necessary. The near-zero KH provides no pH buffer, so stable pH is maintained by active substrate (ADA Amazonia, Contrasoil, or similar) which releases acids slowly.

Temperature is the critical constraint in Singapore. Ambient room temperature regularly exceeds 28°C, which causes increased shrimp mortality and failed breeding in Caridina species. A chiller or at minimum a fan-and-evaporation setup is not optional for serious Caridina keeping here.

Discus and Soft-Water Cichlid Tank

pH 5.8–7.0, GH 1–6 dGH, KH 0–3 dKH, TDS 80–150 ppm, temperature 28–32°C, nitrate below 10 mg/L. Discus require the warmest temperatures of any commonly kept freshwater fish, making them unusual in Singapore — they actually thrive at temperatures that would stress most other tropical species. Frequent, large water changes (50% every 2–3 days for breeding pairs) are standard practice with discus.

Using This Cheat Sheet

Test your water weekly with a reliable liquid test kit (API Master Test Kit or equivalent) rather than strip tests, which are notoriously inaccurate for KH and GH. Record results in a simple log — a note on your phone works — so you can identify trends before they become emergencies. The aquarium water parameter cheat sheet above gives you the targets; consistent testing tells you whether you are hitting them. When in doubt, the team at Gensou Aquascaping is available for water quality consultations and can advise on adjustments specific to your setup.

Related Reading

• Aquarium Water Parameter Log Template: Track and Trend
• Green Water in Your Aquarium: Causes and How to Fix It
• The Complete Water Change Guide: How Much, How Often and Why
• Singapore Water Hardness Map: What Your Tap Water Means for Fish
• 10 Water Testing Mistakes That Give You Wrong Results