High calcium hardness

[Legend]

Ok, I finally got my pool setup for the 2nd time due to some level issues. I'm trying to get my CH down, but can only find draining some of the water to be a way to lower CH. I tested my tap water and it is at 700 ppm. I thought I read somewhere that there is a flocculant you can add to the water to reduce CH. I raised my FC to 10 ppm yesterday, as advised by another member. Today it has drifted down to 7.5. The rest of my numbers are as follows:
PH- 7.4
CC- 0
CYA- 70
CH- 800
TA- 70
SI-.15
PO4- 0
Salt- 4200

Any suggestion??
Thank you in advance!

 

[mknauss]

Only way to reduce CH is to replace the water with high CH with lower CH water.

Do you have a water softener on your home? You might consider using that for part of your fill? Or at least for make up water?

Chemistry looks fine. Best if you use Poolmath and manage your CSI. Keeping it below 0 will keep your SWCG from developing calcium scale.

 

[Legend]

No I don't have a water softener.

 

[mknauss]

Harvest rain water when you can. You will struggle if you have much evaporation.

 

[Legend]

Apparently salt for pools is very different than salt for water softening (Impurities?). Looks like I need a water softener installed. Thanks

 

[mknauss]

The Bismarck City Water department shows their water to be 7 grains or about 120 ppm CH. Odd you are getting 700 ppm (50+ grain) water at your home.

 

[Legend]

I believe they are having issues with certain types of piping materials used in the construction process, mainly the pex piping.

 

[jblizzle]

Apparently salt for pools is very different than salt for water softening (Impurities?). Looks like I need a water softener installed. Thanks

Actually most of us use water softener salt in our pools. Salt is salt, you just have to avoid the type with added rust inhibitors, etc. I personally use solar salt as the only difference between it and pool salt is that the pool salt is ground up finer and costs more.

Can you explain how you are doing the CH test?
Maybe you used a 25x instead of a 10x multiplier? Or had a fading end point?

 

[Legend]

I rinse my comparator tube 3 times before taking the sample at elbow depth in the pool. I get the level to 25 ml mark. Then I add 20 drops of R-0010. Swirl it to mix it. Then I add 5 drops R-0011L Swirl to mix. Then add R-0012 dropwise swirling after every drop until the sample turns red to blue. Then multiply the drops by 10

 

[Legend]

Just curious since I have high CH if it would be wise to run closer to 7.2 PH? That would get my SI down to 0.

 

[jblizzle]

So it took 70 drops to change from blue to red? The SpeedStir helps a lot with the CH test.
If you are that high, use 10ml of water, 10 drops of R-10, 2 or 3 drops of teh R-11 and then multiple the R-12 drops by 25ppm.

You do not need to keep the CSI at 0, but you do not want to let it get too positive. pH in the 7.2-7.5 range would be good.

 

[Legend]

Thank you jblizzle!!!
Thank you for making me revisit my testing procedures.
What a bone head I am! I took the drops times 100! I am at 80 CH which is actually low not high!

 

[jblizzle]

Glad we got that figured out. No need for you to really be concerned about CSI at this point as long as you keep the pH at or below about 8.0

 

[Legend]

Thanks again! You're the best! Now to get my CH up a little??? Isn't SI an important factor in water balance?

 

[mknauss]

Now to get my CH up a little???

Nope -- you have a vinyl liner. No minimum on CH.

 

[jblizzle]

CSI can be important for a plaster pool on both the low and the high side. For a vinyl pool, there is no worry about a low CSI as there is no calcium to pull out of your liner. High CSI can still result in scaling to form for you, but with the low CH, you would have to let your pH get very high for a significant amount of time before it would develop.