Responsibly maintaining calcium level

[johnjmattingly]

Hi everyone,

I just opened our pool up for it's 4th season. Over the last 3 seasons, I've watched my calcium level rise from ~400ppm at fill to yesterday's reading right at 700ppm. As the level continued to rise, I began using CSI measurements through PoolMath in order to keep everything balanced and thus far my plaster and waterline tile grout are fine. CSI as of yesterday is -0.09. However, according to the recommended levels worksheet, my 700ppm calcium score means it's time to replace some water.

I live in Austin, TX and am conscious of our water use. Having to drain/replace approx 45% of my pool water (according to PoolMath) in order to bring my levels back down into the 400s seems somewhat irresponsible in light of the drought, etc.

Is keeping my calcium under 650ppm critical to the successful maintenance of my plaster and equipment, or is it possible to maintain a higher calcium level by tracking CSI more closely?

If draining / replacing is required, do you have specific recommendations on how to perform the drain/replace? I've read the wiki page on Draining, and I have a submersible pump with the ability to match output to input. However, instructions on whether to drain from the deep end or shallow based on TDS and temp seem overly complicated. Is this level of care truly required when draining / replacing water in your pool?

Thanks for all the help and input!

John

 

[mknauss]

Manage the CSI. It typically becomes a bit difficult as you get to 800 ppm CH. The pH and TA must be kept lower and depending on your fill water TA, that can be tough. As your water warms, the likelihood of water line scale increases.

You get rain. You should be able to add rain water. Divert a downspout, drain some water right before a rain, etc.

You show having a cover. Which should reduce evaporation. Why has your CH gone up? What do you use to chlorinate?

 

[JoyfulNoise]

Unless your water is prohibitively expensive (in our area the rates are getting ridiculous), then draining and refilling is the quickest and cheapest option. I don’t see it as being irresponsible at all. You are returning that spent water to the environment and replacing it with fresh water. There is nothing that can be done with that water anyway as it is chlorinated, highly mineralized and people have been bathing in it. It’s the equivalent of rain water runoff going into a gutter - once the rain water touches the ground, it is not considered potable anymore and it’s shuttled into the local sewer system. It’s best to discharge the pool water back into the ground (if you have the room) or into a sanitary sewer line (if you are allowed) and let Mother Nature reprocess it. If people really cared about not wasting water then we would be building far more reservoirs and dams than we do instead of letting trillions of gallon of rainwater go to waste as it discharges back into the environment (see California these days letting all the recent rainwater flow back into the sea..). You’re going to waste more time and energy fighting with water that is out of balance than correcting it and moving on. Believe me, I have been where you are (CH nearly at 1500ppm) and it’s a battle you will lose. Drain, replace, rebalance. It’s a simple as that.

 

[Rancho Cost-a-Lotta]

Try to find a way to perform top offs (due to evaporation) with softened water and you may never need to drain again. Search TFP for options.

Best wishes!

 

[johnjmattingly]

Manage the CSI. It typically becomes a bit difficult as you get to 800 ppm CH. The pH and TA must be kept lower and depending on your fill water TA, that can be tough. As your water warms, the likelihood of water line scale increases.

You get rain. You should be able to add rain water. Divert a downspout, drain some water right before a rain, etc.

You show having a cover. Which should reduce evaporation. Why has your CH gone up? What do you use to chlorinate?

Yes, have a cover and use it. Little rain water typically gets in. The only thing I can think of thats raising the calcium is potentially leaching from the plaster. Or, the fill water from the auto fill is slowly doing it. But the same full water was used during startup that had the pool around 400.

I do have a little water line scale in the grout of my water line tile. But it’s not significant and the feel of my plaster is still nice underfoot.

Perhaps the drain and fill is the only way to go.

 

[Rancho Cost-a-Lotta]

When water evaporates from the pool, the calcium stays behind. Each time you top off, you add more calcium to the pool. This is why calcium levels increase. A water softener will not allow that calcium to get into the pool which will help to stabilize ch levels.

 

[johnjmattingly]

Yes, have a cover and use it. Little rain water typically gets in. The only thing I can think of thats raising the calcium is potentially leaching from the plaster. Or, the fill water from the auto fill is slowly doing it. But the same full water was used during startup that had the pool around 400.

I do have a little water line scale in the grout of my water line tile. But it’s not significant and the feel of my plaster is still nice underfoot.

Perhaps the drain and fill is the only way to go.

Also, I use liquid chlorine exclusively to chlorinate.

 

[proavia]

Your fill water is the source of your increasing calcium levels. When water evaporates, one of the items it leaves behind is the calcium. If you started with a new fill with CH 400 and the entire pool volume evaporated over the course of one year, your CH level will double to 800 in that one year time span.

Rain helps dilute the clacium laden water a little.

As the calcium level increases, it requires a lower pH (still within the 7's) to maintain an acceptable CSI - all other chemical parameters remaining the same.

Here in Arizona, with our dry climate and high evaporation, our CH level will increase by the fill water CH every 9-12 months. This is why many of us used softened water for our autofills.