DIY Reverse Osmosis?

[BurninMoney]

Seems like this topic has been covered here a little bit over the years... but, I'm interested in whether it's possible to DIY a reverse osmosis setup for occasionally dropping CYA and other levels to acceptable levels over time rather than paying $500+ for a truck to do it in 8 hours. Thoughts?

 

[jblizzle]

I do not think you would be able to do it for less than the occasional $500.

I think a small setup would end up having membrane problems and probably have a much higher waste water rate.

You might be able to put a system on your top-off water that would help keep the CH down ... as long as you are not using Dichlor or Trichlor you should not have rising CYA, leaving the climbing CH as the only issue to worry about.

 

[cfherrman]

Could distill the water and toss the brine water, still not fast easy or cheap, but cheaper

 

[JoyfulNoise]

The cheapest way to deal with the buildup of chemicals in water in most areas is to simply drain and refill. I know no one likes to see thousands of gallons of water go down the drain, and it can be inconvenient if you are on a well, but it is almost always cheaper to drain and refill.

Draining and refilling my 16k gallon pool would cost somewhere in the neighborhood of $250-$300 (using municipal water and having to pay for the sewerage fee even though I would drain it out onto my property). RO in my area costs at least $300 to perform and will still require me to supply both the electrical energy to run the pumps and additional make-up water to replace the waste fraction that RO generates. That would cost me at least another $100 dollars in water. Even with all that, the RO process would only get me to about 250ppm CH and it would take 3 to 4 days for the RO process to be completed. I can drain and refill my pool in about 2 days.

Unfortunately, there really is not any small scale filtration technique that will work for residential pools. Once a pool is refilled with fresh water that's low in CH and CYA, then the best approach is one of prevention - don't use stabilized chlorine products and, if possible, use only water from a softener to refill a pool.

 

[psumma]

The cheapest way to deal with the buildup of chemicals in water in most areas is to simply drain and refill. I know no one likes to see thousands of gallons of water go down the drain, and it can be inconvenient if you are on a well, but it is almost always cheaper to drain and refill.

Draining and refilling my 16k gallon pool would cost somewhere in the neighborhood of $250-$300 (using municipal water and having to pay for the sewerage fee even though I would drain it out onto my property). RO in my area costs at least $300 to perform and will still require me to supply both the electrical energy to run the pumps and additional make-up water to replace the waste fraction that RO generates. That would cost me at least another $100 dollars in water. Even with all that, the RO process would only get me to about 250ppm CH and it would take 3 to 4 days for the RO process to be completed. I can drain and refill my pool in about 2 days.

Unfortunately, there really is not any small scale filtration technique that will work for residential pools. Once a pool is refilled with fresh water that's low in CH and CYA, then the best approach is one of prevention - don't use stabilized chlorine products and, if possible, use only water from a softener to refill a pool.

I know this thread is getting old, but I have a RO trailer in Southern California, and I can say that you are not accurate when you say that the cheapest way to deal with "buildup" is to drain and fill in most areas. Your statement might be true in your area, but it is not accurate out here, and people read this forum from everywhere. My pool is 18,000 gallons and would cost $500. A 40,000 gallon pool about 2 miles from here (as the crow flies) is in a different water district and would only cost $140. There are places that an 18,000 gallon pool costs $1100 to fill, and some places that are prohibited by law from draining and refilling as a water maintenance practice.

Most RO processes for pools are finished in less than a day- not 3-4 days. The RO process, if performed on the full pool will leave the Total Dissolved Solids at less than 100ppm. Most RO companies shoot for 200ppm calcium as that is the low end of what is considered acceptable for plaster. I carry calcium prills with me to bring the calcium level up from the usual 50ppm when my trailer is done.
Something is also wrong with the math for your water costs. A decent RO will run anywhere from 5-15% waste. If a pool costs $300 to fill, then 15% is only $45. I don't know of any RO units out here that require the homeowner to provide the power. Mine has an onboard generator.

There is also the issue of a pool popping out of the ground. I never really thought of this as much of an issue, but it does happen. When it does happen, draining and refilling ends up costing quite a bit more than RO! I met with a school district out here about using RO on their water, because one of their high school pools popped out of the ground, and cost them over $140,000 just to cut up and dispose of the concrete!

I just wanted to take the time to point out the differences in area, because this thread shows up on the first page of a few search engines, and inaccurate information would certainly hurt my business.

As far as a small, individual unit for pools, they would have to generate a lot of pressure to be efficient.