Auto Aqua Digital inline TDS Titanium S1
Part no.
TDS-100S
In the box
3 items
Test range
0 to 999 ppm TDS
Test method
Inline digital meter
Kit life
Battery life 1 year
Auto Aqua Digital inline TDS Titanium S1
Tells you the day your DI resin gives up, not the week after.
The AutoAqua Digital Inline TDS Titanium S1 is a permanently plumbed meter for total dissolved solids (TDS, the mineral load left in your water) on RO and RO/DI systems. It reads 0 to 999 ppm at 1 ppm resolution with ±2% accuracy through a titanium probe, runs about a year on a single CR2032 cell, and magnet-mounts beside the filter housings. The S1 ships with one union tee, so it monitors one point in the line – decide which point matters most before you cut any tubing.
Key features
- Titanium probe – AutoAqua specifies titanium for corrosion resistance in a fitting that stays wetted permanently.
- 0 to 999 ppm at 1 ppm resolution – fine enough to see DI resin exhausting a single point at a time rather than in a jump.
- ±2% stated accuracy – close enough that a 3 ppm reading is a real 3 ppm, not rounding.
- Backlit LCD – readable inside a dark cabinet without a torch.
- Auto power off after 3 minutes – why one CR2032 lasts about a year on a meter that is always plumbed in.
- User calibratable – drift can be corrected against a reference rather than replacing the meter.
- Integrated magnet – sticks to the filter bracket or housing clip, no drilling.
Specifications
| Measurement range | 0 to 999 ppm |
|---|---|
| Resolution | 1 ppm |
| Accuracy | ±2% |
| Measurement points | One |
| Probe material | Titanium |
| Display | Backlit LCD |
| Auto power off | After 3 minutes |
| Calibration | User calibratable |
| Mounting | Integrated magnet |
| Water connection | Quarter-inch push-connect union tee (one supplied) |
| Power | CR2032 lithium cell (one supplied) |
| Battery life | About 1 year |
| Manufacturer part number | TDS-100S |
Which Titanium do I need?
| Model | Union tees supplied | Points monitored at once |
|---|---|---|
| Titanium S1 (TDS-100S) | 1 | 1 |
| Titanium S2 (TDS-200S) | 2 | 2 |
| Titanium S3 (TDS-300S) | 3 | 3 |
All three share the same 0 to 999 ppm range, 1 ppm resolution and ±2% accuracy. The only thing that changes is how many places in the line you can read at once. This listing is the S1.
Where to put the single probe
Because the S1 reads one point, where you tee it in decides what the meter can tell you.
- After the DI resin – the number your tank actually receives, and the reading that should sit at 0 ppm. This is the usual choice.
- After the RO membrane, before DI – shows membrane performance directly, but says nothing about what finally leaves the unit.
- On the feed line – your starting point. Useful to know once, rarely worth a permanent probe.
If you want membrane performance and final product water at the same time, that is two measurement points, which is the S2 rather than the S1.
Reading the number
| Where you read | What the number tells you | What a change means |
|---|---|---|
| Feed line | Your incoming supply TDS | Changes what the membrane has to remove, and shifts seasonally on some supplies |
| After the RO membrane | How much the membrane is removing | Express it as rejection: (feed minus product) divided by feed, times 100. A falling percentage means the membrane is wearing |
| After the DI resin | The water your tank receives | The DI stage exists to bring this to 0 ppm. Any reading above 0 ppm means the resin is running out |
The meter reports the water; it does not schedule your maintenance. What it gives you is the date the number moved.
Suitable for, and not suitable for
Suitable for:
- RO and RO/DI systems plumbed in quarter-inch push-connect tubing
- Freshwater and marine keepers making their own top-off and mixing water
- Watching one point continuously instead of dipping a handheld meter
Not suitable for:
- Reading aquarium water – a stocked tank, and marine water in particular, sits well above the 999 ppm ceiling
- Saltwater lines, for the same reason
- Anyone who needs feed and product readings at the same moment – that is the S2
- Tubing other than quarter-inch push-connect, without an adaptor
What's included
- Titanium S1 digital inline TDS meter
- CR2032 lithium battery x 1
- Quarter-inch push-connect union tee x 1
Not included
- RO or RO/DI filter unit
- Quarter-inch RO tubing
- Additional union tees for a second measurement point
- Calibration reference solution
Care and maintenance
Expect about a year from the CR2032, helped by the three-minute auto power off. Keep the display body out of direct splash even though the probe itself is titanium. If the reading drifts against a known reference, recalibrate rather than replace.
Goes well with
- Reef Pure Mixed Bed Colour Indicating DI Resin – the stage the 0 ppm reading is watching
- Reef Pure Reverse Osmosis Membrane – what a falling rejection percentage points to
- Reef Pure 4 Stage Essentials+ – an RO/DI unit to tee the meter into
- AutoAqua Smart ASOV – fills the reservoir automatically once you trust the water
- AutoAqua DC Solenoid Valve – feeds that water straight to a top-off system
- The full AutoAqua range
Warranty and delivery
Ships as a standard parcel. Any manufacturer's warranty offered on this meter applies in addition to the consumer guarantees you have under Australian Consumer Law, which cannot be excluded.
Common questions
Does the Titanium S1 read two points at once?
No. The AutoAqua Titanium S1 ships with one union tee and monitors a single point in the line. Reading two points at once, such as before and after the DI stage, requires the Titanium S2, which supplies two tees.
Can it stay plumbed in permanently?
Yes. The probe is titanium for exactly that reason, and the meter powers down after three minutes so a single CR2032 lasts about a year in continuous installation.
Will it read my aquarium water?
No. The meter tops out at 999 ppm, which is a purified-water range. Stocked aquarium water, and marine water especially, reads far above that ceiling.
What battery does it take?
A single CR2032 lithium cell, one of which is supplied. AutoAqua rates battery life at about one year.
Can the meter be calibrated?
Yes. The Titanium S1 is user calibratable, so a drifting reading can be corrected against a reference solution instead of replacing the unit.
