Reducing High Calcium Levels in Pools

[cfherrman]

Pretty cool with ro, have some questions

How much waste water was used?

How many watts was used

What was resulting ch?

 

[Jimbarstow]

Pretty cool with ro, have some questions

How much waste water was used?

How many watts was used

What was resulting ch?

You lose about 15% of the water during the process. For us, the make up water from our well was about 350 ppm Ca so that increased the run time. The process runs until it hits the desired endpoint which we set at 160 ppm Ca. The equipment is all contained in a trailer and includes a 20 kW diesel generator.

At the end, the water was perfect. It even looked different although that might be because the water was run through heavy duty filters continuously for 24 hours.

 

[del]

What was the cost of RO vs drain and refill?

 

[Rancho Cost-a-Lotta]

A company based just north of you in Orange County, CA charges $600 for RO. That includes all chemicals (except salt) to get your water balanced.

 

[cfherrman]

When looking for RO you also have to ask about waste water and engery cost, in the above example they used a generator instead of house power and only a meager 15% waste water so depending on the cost get probably got a good deal

 

[Rancho Cost-a-Lotta]

Similar for the Orange County example. The trailer is self-contained and 15% water loss. It takes less than one day.

 

[duraleigh]

charges $600 for RO.

What size pool?

 

[Rancho Cost-a-Lotta]

For mine...IIRC, up to 20K gallons.

 

[onBalance]

Yes, using RO systems costs a little more, but are a very good alternative and work very well. There are a few companies in Southern California and Arizona that offer that service. As an added benefit, using RO will also reduce the CYA and TDS levels if high.

 

[onBalance]

Is there, or will there be a formula for the amount of soda ash to add given other applicable variables?

I don't think the above question was answered. I offer a simple and general guide for performing this procedure.
One pound of soda ash will yield approximately one pound of calcium carbonate. (The actual number is 0.944 lbs.)
And one pound of calcium carbonate translates to 12 ppm (of CH) in 10,000 gallons of pool water.

However, the results can vary somewhat due to other variables. One variable is when the CH level is very high and the water has a very high CSI, then more than one pound of calcium carbonate may be precipitated. On the other hand, a low beginning CH and fairly balanced CSI may not yield much calcium precipitate. A difference regarding the concept of "seed crystals" forming can affect final results.

I also do not recommend trying this procedure with small doses of soda ash as much of the soda ash may simply dissolve, raise the pH and TA, and not produce the desired results.

 

[JoyfulNoise]

About a year ago I spent several days, and many note pads, working out the lime-softening process for my pool. IN the end, the cost of the chemicals involved plus all of the convoluted steps needed to make it work without scaling my pool walls with calcium was just not worth it. Lime-softening is a great treatment process for potable water distribution systems, not so much for swimming pools. As for RO, most of the companies around here use cheap, low pressure RO systems that would be lucky to get you a 25% waste fraction....and most of the vendors I talked to stopped doing RO because it was too expensive to keep up the equipment. Even at a cost of $600, I could fully drain and refill my pool as well as get the tiles cleaned for less.

I've managed my water all the up to a CH of 1500ppm, not fun but doable. At the end of the day, the most cost effective solution was adding a whole-house water softener to my home with a line connected to the autofill. With partial drains and refills plus a steady diet of zero CH fill water, my pool's CH is slowly drifting down.

 

[QueHales]

Having performed many, many fresh plaster start-ups, as well as soda ash softening procedures, I can attest that the precipitate that is formed in the two processes is very similar... It will not adhere to the pool interior surfaces in the relatively short amount of time required to filter it out. This usually takes three days or less, and the pool is brushed and filtered in the mean time. For new plaster, we brush, filter, and often use a suction-side cleaner that has brushes only in contact with the new plaster. For soda ash softening, we have used other types of suction-side cleaners attached to the filter. We have as yet not seen precipitate attach.