If Both Brands Read 0 PPM, What Are You Really Paying For?

A brand article from Rhodi · Pure-water buying guide

What a TDS meter leaves out when you compare filtration systems for professional window cleaning.

Two pure-water systems can show the same 0 PPM reading and carry very different price tags. The meter will not tell you whether the difference is worth paying.

That leaves a window cleaner with a harder question: what should you compare once both systems can produce the water you need?

The answer starts with a working day. How much water reaches your brush, what it takes to keep producing it, and how the equipment fits your route all matter after checkout.

A matching reading can hide a different workday

A handheld TDS meter estimates dissolved solids from the water’s electrical conductivity. A 0 PPM display is a useful output check, within the meter’s limits. It is not a complete test of water quality or a rating of the equipment around it.

It tells you nothing about how much water the system can supply to your brush, how easy the housings are to service, or what replacement filters will cost.

A higher-priced system may offer differences that matter to your work. A lower-priced system may already meet your needs. Make the seller’s specifications and ownership details explain the difference.

Your water and workload belong in the same calculation

Start with the tap water you expect to use on jobs. Its TDS reading gives you a starting point for estimating the dissolved-solids load the filters will face.

Then estimate the gallons of pure water you expect to use each day. Resin life described as “a few months” means little without knowing how much water passed through it and what that water contained.

In an RO/DI system, reverse osmosis removes most dissolved salts before the water reaches the DI resin. Reducing that load can extend resin life compared with feeding the same source water straight through DI. Pre-filters, membrane care, and the separate reject-water stream also belong in the ownership calculation.

That is why another cleaner’s refill schedule is a reference point, not your budget.

Put your own water into the estimate

Enter your source-water TDS and expected gallons per day to estimate filtration costs. Use the result as a planning guide, then check the assumptions and replacement prices for your setup.

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Ask how much water reaches the job

A flow claim needs its test conditions. RO output changes with feed pressure, water temperature, and dissolved-solids concentration, among other factors. A maximum figure cannot tell you what a particular tap will deliver.

Check pressure while water is running, along with the available supply volume. Then compare the system’s operating guidance with the hoses, brushes, and number of poles you plan to use.

Pressure and flow answer different questions. A pressure reading does not tell you the gallons arriving at the brush each minute. For direct-fed work, usable output needs to support your rinse. If you make water into a tank ahead of time, production needs to fit your filling schedule.

When comparing systems, ask whether the quoted output requires a booster pump. Include any needed pump, power source, hoses, and fittings in the setup price.

Price the replacements before you need them

Open the replacement-parts information while you are still comparing systems. Find the pre-filter, RO membrane, and DI resin the model uses. Check their prices, compatibility requirements, and how you access them for maintenance.

This is one of the practical choices behind the Rhodi 0 Flow. We use standard replacement filters and accessible housings, so you can source compatible replacements from us or another supplier. Check the required size and specification before substituting a part.

Also consider the jobs around the cleaning: loading the system into your vehicle, moving it across the property, and storing it between uses. Weight, dimensions, and service access deserve space beside the purchase price on your comparison sheet.

Read what “support” and “warranty” actually include

A warranty headline needs a policy behind it. Check which parts are covered, for how long, what maintenance is required, and what is excluded.

Rhodi’s system policy provides a limited lifetime warranty on the housing and frame for the original retail purchaser, plus a 12-month limited warranty on factory-supplied non-consumable components and workmanship.

We also provide lifetime support for the original purchaser while they own the system. Support does not mean free consumables or unlimited replacement parts. Knowing the distinction gives you a clearer comparison before you buy.

Choose the capacity your route can use

The Rhodi 0 Flow uses a single RO membrane. The 00 Flow uses two for higher production potential. Both use RO/DI filtration, but actual output depends on the operating conditions.

Start with your current work and the jobs you realistically expect to add. If you plan to run more than one pole, check the combined water demand against expected output. A larger system still needs a suitable water supply.

Before choosing a package, check what is included. The filtration system, pole, brush, hose, and connections all need to work together; a system-only price is not the same as the price of a complete cleaning setup.

Make the price earn its place

Bring your water TDS, expected daily use, operating pressure, and pole requirements to the comparison. Then look at replacement costs, construction, and the support behind each option.

At Rhodi, we want professional pure-water equipment to be more accessible. Compare our systems against the work you need them to do, and choose the setup whose features you can put to use.