Case Studies: Recycling Water in a Residential and Commercial Pool

photo of a commercial pool

TrailerPool owners in the Southwest often come across problems during the hot summer months. High temperatures accelerate evaporation, which elevates the calcium level in the pool. That in turn requires pool owners to add more water — and since our fill water is loaded with calcium and other hard minerals, that means more calcium develops.

And as you likely already know, the minerals that concentrate in a pool can stain the tile and surface of the pool and damage equipment. So all around, it’s a very frustrating problem for pool owners, yet it’s very common in Southern areas.  

Pool professionals generally suggest draining a pool when TDS climbs above 3,000 ppm, CYA is over 100 ppm and calcium is above 600 ppm. However, draining seems wasteful, especially considering the cost of water and drought conditions that exist in many parts of the country. 

But we knew there had to be a better way. We at Pool Services Technologies (San Diego, Calif.) put our heads together and designed a mobile filtration system that could create balanced water by recycling it. The trailer we created is designed to process water from any size swimming pool with any surface. 

We use the system on both residential and commercial pools, and aside from processing time, the procedure remains the same. Let’s go into a case study for a homeowner and a commercial property. 


A Skeptical Homeowner

The water in this swimming pool (see left) was three years old and consistently cloudy. After the water was tested in a pool store, it was determined the calcium was 820 ppm, TDS was 4620 ppm and CYA was 80 ppm. The homeowner’s main concerns were calcium staining the tile and difficulty in keeping the pool clear.

While the pool store recommended draining and refilling the pool, the homeowner had been doing so for the past 20 years and was concerned she’d just end up in the same position. Looking for an alternative, she gave us a call, even though she was skeptical our process would work. 

When you have a service that seems too good to be true, it takes a little more time to coax a homeowner into giving it a shot. For us, the key was to make sure this homeowner knew all the benefits. Aside from how our process would conserve 85 percent of the 24,000 gallons of water in her pool, we explained that the process would take 14 hours compared to two or three days for a typical drain and refill. The filtered water would be better than tap and, after completion of the service, the water would be crystal clear, soft and, because of fewer contaminants, she will lower her chlorine usage. 

After running the pool water through our reverse osmosis system we conserved 19,500 gallons, calcium was left at 150 ppm, TDS was 700 ppm and CYA was 0 ppm. She confirmed the results in the pool store and said she would never drain her pool again.

The Busy ResortTrailer Commercial

As mentioned earlier, the process for both commercial and residential pools is the same. But commercial pools often have other factors that need to be taken into consideration. 

For example, it’s recommended that the water in a commercial pool be changed more frequently due to the amount of swimming that takes place. In the case of this pool a 180,000-gallon plaster pool at a busy resort in the middle of summer, the calcium was 710 ppm, TDS was 8,162 ppm and CYA was 100 ppm. Naturally, the resort didn't want to shut down the pool for a week and potentially lose business while replacing the water. 

Because completely shutting down the pool was unthinkable, the resort contacted us. They believed in the service but were concerned about the time it would take, safety issues caused by exposed hoses and noise pollution from our trailer. 

After taking a tour of the property, we found a place we could park the trailer that was close enough to filter the swimming pool yet out of the way enough so guests weren’t likely to trip on hoses. (See picture on the right.) Noise is never a concern since the trailer is fully insulated, but we did have to set something up to keep the guests away from the intake and return hoses. The process was planned to take five days to complete, but since you can continue swimming in the pool during filtration, it was very attractive to the resort.

After filtering the pool for five and a half days, the calcium was lowered to 160 ppm, TDS was 820 ppm and CYA was 0 ppm; we conserved 145,000 gallons. The water was perfect, the resort didn’t lose any downtime and they were left with a swimming pool that is easy to take care of. (See the picture at the top for the final outcome.) In the future it was determined that the resort will filter the pool every 6 to 8 months. 

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