To say that Pool Services Technologies is rolling out a new product wouldn’t be accurate because this product doesn’t roll. The Vista, Calif.-based company known for its mobile filtration units has developed a decidedly less mobile purification system.

PST’s trailers housing sophisticated filtration equipment have been on the road for six years now, allowing technicians to purify pools through reverse osmosis. Each unit sits at curbside using a hose to draw water from the pool through the system. Dirty water comes in as clean water goes out. The pool is never drained, which, in California’s drought-stricken climate, is the firm’s big marketing hook.

But the company found that trailers present a hitch: Not all pools are accessible from a street, parking lot or driveway. Rooftop pools have proven problematic, and others are tucked behind hotels and resorts where a hose can’t reach. Extending the hose isn’t always an option because it can slow down water flow.

“Water has to hit the membranes at a certain velocity,” said Ken Scheer, director of marketing.

That’s why the company now is marketing an in-line system. It’s plumbed into a pool’s existing equipment as a permanent fixture, attached to a wall or mounted on a skid. The process is the same, Scheer said. Sensors are placed within the system of tubes, UV light and tightly wound coils. When they detect high levels of total dissolved solids, valves are triggered to divert water from the conventional filter to the RO process. Once the water is purged of excessive calcium, cyanuric acid and other undesirables, the pool’s equipment resumes its normal operation.

For commercial facilities, the appeal is this: There’s no need to close the pool to bring water back into balance.

Scheer said they haven’t installed any of the systems yet, but the company has been fielding interest and is meeting with major hotel chains.

“With this system, we can now start helping resorts that we couldn’t gain access to,” he said.