Minimum Calcium Needed

[JoyfulNoise]

The cost was $525.

I'm not sure how much water went to waste. I do know that he hooked up a garden hose from my house to the trailer to replenish water. He also had a hose from his trailer to my sewer clean out to dump the waste. The water in the pool dropped by 1 to 1.5 inches during the process, but never below the tile line. My autofill took care of the rest after he was done.

Thanks for the info.

You can assume pretty reliably that the waste water rejection ratio is pretty close to 15-20%. So worst case scenario is that you'll see an extra 1,600 gallons (2.1 CCF) of water usage on your water bill (assuming you're on municipal water). Assuming the RO rates are regional (I'm down in Tucson), $525 would be more than the cost of me pumping my pool water out and simply refilling with municipal water (20,000 gallons roughly costs $156 if you subtract out the sewerage rate or $260 if you include sewer). However, I don't like the thought of flushing 16,000 gallons down my waste water pipe, so I might consider RO in the future.

Good luck with your new water!!

 

[jv92red]

What about after a RO treatment having a household sized RO system installed on the auto fill? Is this a possibility perhaps not at the auto fill location near the pool but near the equipment pad where the auto fill is plumbed from house water?

 

[Patrick_B]

Based on your pool volume alone, that puts the price very much in line with what I was quoted. How long did the process take on yours? They estimated mine would be about 19 hours.

What about after a RO treatment having a household sized RO system installed on the auto fill? Is this a possibility perhaps not at the auto fill location near the pool but near the equipment pad where the auto fill is plumbed from house water?

Absolutely could be done if you can afford it. Pool pad might not be the best place but location doesn't really need to be there. Indoors is really a must however.

 

[Ale_Brewer]

It is not true that when TA exceeds the CH that there will be no scaling nor is it true that the "temporary" hardness does not produce scale.

I may be wrong about this, and I am just a product of my state-approved education here, but the visible "scale" you can get from this should be able to be removed easily without the need for a strong acid.

In regards to ROs, I work with them every day. The best recovery rate you can expect under normal circumstances is about 75%. You can push it slightly higher than that in some situations but that's a good figure to shoot for on an average "high-efficiency" RO. Standard rejection rate is about 98-99%. Pre-treatment also has a lot to do with both of these, such as removal of chlorine and hardness. Chlorine will oxidize the membrane causing rejection rate to go down and hardness will scale the membrane causing recovery rate to go down and pressures to go up. If you are looking to get a "residential size" RO, you can expect much less efficient performance such as a 50% recovery rate, but you can maintain a high rejection rate with proper pre-treatment. If all you are trying to eliminate from your fill water is calcium, a cheap softener would be more appropriate and cost effective. You will have to decide whether you want to replace the calcium with sodium or potassium though. Sodium is about 25% of the cost of potassium but overall cost over a year would probably be pretty low anyway.

 

[chem geek]

Fresh scale is usually easily removed by maintaining the water with a negative CSI. It does not matter whether the scale was formed from high TA or from high CH. Calcium carbonate scale can become harder to remove as it ages (partly because it gets thicker and partly because it can exchange impurities that weaken it, such as magnesium, with calcium).

The kind of scale that is hard to remove are other types of calcium scale including calcium phosphate (when both are very high; see this link) or calcium sulfate (see this link).

 

[artemous]

If you have a few bucks, have a water softener put on the pool water feed. It will remove all calcium from the incoming water. Won't do anything for what's already there. Just remember on a fresh fill you'll have to bypass it for the first 20% then regenerate every so often depending on size. I did on mine and had a fresh fill of 170. In my case softener I used was already very old and promptly broke after that.