AutoAqua Inline TDS Meter - Titanium S2

Are you tired of big, boxy, hard-to-read TDS meters? So are we! That's why we built the AutoAqua Titanium Series TDS meters. They are small, easy-to-use, and have a big bright screen to make checking your TDS fast and easy.

The Titanium S2 also has a magnetically coupled controller to make it easy to pick up and stick back on the metal frame of your reverse osmosis system. There is no other TDS meter on the market like it. Browse all our water testing kits or our complete maintenance & water care lineup.

Key Features

• Inline installation — connects directly to your RO/DI system tubing so you can monitor purity continuously, not just when you remember to test.
• Magnetic mount — the display unit attaches to the metal RO/DI frame magnetically and pops off in your hand for quick reading.
• Dual-probe ready — Titanium S2 monitors both inlet and outlet TDS so you can see exactly how much your DI resin is removing in real time.
• Large bright display — readable at a glance from across the room.
• Compact footprint — fits any RO/DI setup, even tight under-sink installs.

Why You Need Inline TDS Monitoring

RO/DI water purity is the single most important variable for a healthy reef tank. As DI resin exhausts, TDS creeps up — sometimes within days of a fresh fill. A handheld TDS pen only tells you the water quality at the moment you test; an inline meter shows you the trend so you know exactly when to swap DI resin (target: 0 ppm out, replace at the first sign of creep above 1–2 ppm).

Specifications

Recommended Pairings

• IceCap Dual DI Filter Canister — inline polishing DI for the cleanest possible RO/DI water
• IceCap RO Booster Pump Kit — improves rejection rate and output speed
• IceCap 4-Stage RO/DI System — full RO/DI builds in 75/100/150/200 GPD
• All water testing kits — Ca, Alk, Mg, nitrate, phosphate, and more
• Maintenance & water care supplies

FAQ

What does TDS actually measure?
TDS stands for Total Dissolved Solids — the total concentration of ions in the water expressed in parts per million (ppm). For reef and freshwater tanks, your RO/DI output should read 0 ppm; tap water typically reads 100–500 ppm.

How do I install it?
The probes splice into your RO/DI tubing — one before the DI stage (inlet) and one after (outlet). Most installations take under 10 minutes with standard quick-connect fittings.

Is it accurate enough for reef tanks?
Yes — the Titanium S2 is accurate to ±2% and is designed specifically for the aquarium hobby. The dual-probe inline readout is more informative than a standalone pen meter for ongoing reef use.

When should I replace the DI resin?
Replace at the first sign of TDS creep on the outlet probe (above 1–2 ppm). Mixed-bed color-changing resin also gives a visual cue, but TDS is the most reliable indicator.