Calcium Hardness - so confused?

[M&M Blackjack]

Hello - our CH is currently 47. With a salt water, gunite pool I see recommended is around 350. TFP app says I need to add 67 lbs to get there. That seems like an INCREDIBLE amt to have to add and I am more confused now after researching for days than I was before.

#1 - What is the best method to add, I have read to dissolve in a bucket and I have also read NOT to do that.
#2 - What is the best type of Calcium to add - I have read Calcium Chloride and also Calcium Carbonite... getting mixed info on both
#3 - Does adding Calcium Chloride add salt to the pool, especially with the amt I need to add? My salt level is currently 3,500 so I dont want to add any salt to my pool

Obviously, with our CH being so low I need to get something started but I also dont want to do it incorrectly or have to drain/replace water because my salt gets too high. I have JUST gotten every other chemical balanced and CH is the last thing, so having to replace water is NOT ideal at this point.

Thanks for any suggestions.

 

[SecoSteve]

How did you come up with 47 CH? From YOUR TF-100?

 

[ajw22]

Do not dissolve calcium in a bucket. Broadcast calcium on the top of the water.

Be careful in dissolving calcium as it it exothermic and you can burn yourself.

Calcium Hardness - Further Reading

www.troublefreepool.com

 

[sande005]

You want pure Calcium Chloride. Yes, it can take a lot.

In the past, I was able to get 50lb bags of "Dowflake" from local suppliers. That has been hard to find, locally, as of late. Pool stores/suppliers seem to offer it in small, very highly priced, amounts.
I last ordered this: Snow Joe 20 lb. 94% Pure Calcium Chloride Ice Melt Pellets MELT20CPP - The Home Depot

Shop very carefully - many "ice melt" products have many other formulations and additives. You may find alternatives with a slightly higher level of purity, but at a big cost increase.

In my Dowflake days, I just broadcast it into the pool. But one incident where I dumped in too much in one spot resulted in the heat generated leaving a mark on the liner. So a routine of adding 5 lbs at a time, constant brushing until gone, and repeat. While not terribly slow, it is not a fast dissolver like say salt, either.

I went against advice the last couple of times, and added it to a 5 gal pail of cold tap water. Used my cement stirrer drill attachment to mix it well until dissolved in the pail. Then poured it in the pool. Repeated as required. The pail did get warm, but not dangerously so. But I was cautious with smaller amounts and starting with cold water. Maybe very foolish, maybe lucky....

 

[M&M Blackjack]

How did you come up with 47 CH? From YOUR TF-100?

Yes, last week I tested with TF-100 first and was around 45, then took sample to pool store and got 47. Tested again last night with my TF-100 and is between 40-50 so I am going with the 47. Meaning 4 drops of R0012 was a very very slight blue, 5 drops was more definite blue.

 

[reggiehammond]

Count drops until the color changes and with one additional drop, it changes no further. Subtract the last drop that caused no change and that's your number. It's unwise to guesstimate; trust the drop based testing.

Also stay out of the pool store if you value your sanity and your $$.

 

[proavia]

What is your water source?

For the CH test, use a 10ml water sample.
Continue to add drops until the last drop does not further change the color - and then subtradt the last drop that doesn't change the color. Each drop counts as 25ppm.

Also, test the pH, TA and CH of your fill water and report those here.

 

[M&M Blackjack]

Count drops until the color changes and with one additional drop, it changes no further. Subtract the last drop that caused no change and that's your number. It's unwise to guesstimate; trust the drop based testing.

Also stay out of the pool store if you value your sanity and your $$.

ok, so then its 50... 3 away from the 47. Regardless, its extremely low and I need to get clarification on the best way to do it and also the question DOES IT ADD SALT to your pool? First time to the pool store and last. I simply went to get some kind of baseline for my CYA as it was not even registering with my Taylor kit... at the time I went it was a 5. I now have it at 65, I have learned enough from here and much other research that they werent able to sell me a single thing. I got water tested, ignored what they told me on some things (like CYA needed to be 150 because we are in Tx) and walked out.

 

[reggiehammond]

65 is also not a valid result as the CYA test is logarithmic. You need to round up to next 10, so 70.
Pool store testing is notoriously inaccurate. Taylor drop-based testing is the gold standard; trust it.

No, calcium does not add meaningful salt. Purchase a high quality calcium chloride and add it to get to low end of the scale. You should test your incoming water (muni or well?) to confirm the calcium content. As you add water to pool to account for evaporation, the calcium remains behind and builds up over time.