TDS: The Hidden Purity Metric in Your Aquarium

Your water looks pristine—yet the TDS pen flashes 600 ppm. What’s going on? Total Dissolved Solids (TDS) is the sum of every ion and tiny particle (< 2 µm) floating unseen in your tank. Think minerals, salts, metals, even organic waste. Get TDS right and fish breathe easy; ignore it and they fight through “thick” water.

What TDS Actually Measures

• Calcium & magnesium (hardness builders)
• Sodium, potassium, chloride (salts)
• Trace metals & heavy metals
• Organic residues—fish waste, plant decay, humic acids

Higher numbers mean denser water. The Aquarium Solution notes that elevated TDS can even fuel algae blooms.

Ideal TDS Ranges

Aquarium Type	Recommended TDS	Why
Community tank	150 – 500 ppm	Comfort zone for most tropical species
Neocaridina shrimp	180 – 250 ppm	Stable minerals for healthy molts
Soft-water fish (Discus)	80 – 150 ppm	Low conductivity, gentle osmotic pressure
Reef tank (RO/DI)	< 5 ppm pre-mix	Near-pure base water before adding salt mix

Why Extremes Cause Trouble

Too low: mineral deficiencies—plants yellow, shrimp struggle to molt.
Too high: osmotic stress, heavy breathing, algae boom. 2Hr Aquarist recommends watching TDS trends as an early warning for over-feeding or filter issues.

Common Reasons TDS Creeps Up

• Evaporation: water leaves, minerals stay behind.
• Over-feeding: excess food breaks down into nitrates & phosphates.
• Hard tap water or incomplete RO filtering.
• Plant fertilizers & mineral additives.

How to Keep TDS Under Control

1. Quick checks: a TDS pen gives a reading in seconds.
2. Track trends: the Aquaware Starter Kit logs TDS every 12 h (Free) or hourly (Premium) and plots clear graphs.
3. Water changes: rising TDS = time for a partial change.
4. RO/DI & re-mineralize: for sensitive species, start with pure water and add precise minerals back in.

TDS & Water Purity—The Connection

Clean water shows a moderate, stable TDS. Sudden jumps hint at hidden waste or a change in your tap supply. Kactoily stresses that watching the direction of change is more useful than chasing an exact number.

How the Aquaware Starter Kit Helps

• Real-time alerts: push notification for +30 ppm in 24 h.
• Historical charts: instantly see if your last water change lowered TDS.
• Sustainable & modular: PLA housing, plastic-free packaging, upgrade later with pH or EC probes.

Full install guides live in our online docs.

Takeaway

TDS is your quick purity litmus test: a single ppm number uncovers hidden buildup and mineral gaps. Pair a basic meter with smart tracking from the Aquaware Starter Kit and you’ll keep dissolved solids—and fish stress—under control.

Questions? Reach out anytime—we’ll help you find the perfect TDS sweet spot!