Got started, fixed algae overnight

[mgtfp]

Keep in mind that chlorine loss is a percentage of the current FC. If you are loosing 0.5ppm at FC 6.5ppm, then you are loosing loosing about 8% of your FC per day. That means at FC 9ppm, the loss after day one will be about 0.75ppm. After 10 days, your FC will be at 9ppm x (1-0.08)¹⁰ = 3.9ppm, which is under your min FC.

As Marty suggested, bring it to SLAM, i.e. 20ppm in your case with CYA 50.

After 10 days, you should return to about 20ppm x (1-0.08)¹⁰ = 8.7ppm. That gives you enough buffer and starts with a clean situation.

 

[gaajar35]

Sounds good. Thanks!

 

[gaajar35]

FC is in control and all going well. CH is (and has been) out of range (100 right now). PoolMath says I need to increase it to 450 target. Is that correct for a concrete pool? Also, recommendations on where to get Calcium Chloride? Thx!

 

[PoolStored]

PoolMath says I need to increase it to 450 target. Is that correct for a concrete pool?

What is the CH of your fill water?

 

[gaajar35]

What is the CH of your fill water?

25

 

[PoolStored]

25

Sacramento is pretty "evaporative" no? Any idea how much your water evaporates? Or better said, how much water do you add monthly? That TA is fairly low (which is good for you!)

The reason for the evaporation question is, CH, like CYA can only be removed by replacing water with lower CH water, or reverse osmosis. Both can be expensive propositions. You want to balance protecting your pool plaster with the need to replace water when your CH gets very high.

I'd raise it to 250. With evaporation and fill, it will rise over time.

 

[gaajar35]

Got it. Thx! Yes, very evaporative normally. I also seem to have a small leak somewhere (nowhere obvious. will need to research that next). In terms of the Calcium chloride, get it from a pool store? Any recommended sources?

 

[PoolStored]

Got it. Thx! Yes, very evaporative normally. I also seem to have a small leak somewhere (nowhere obvious. will need to research that next). In terms of the Calcium chloride, get it from a pool store? Any recommended sources?

I'm the odd ball here, it is the one chemical I buy from the pool store (dowflake)...because it is not much more expensive (like 5$ more) and is pure.

If you find a source, like Snow Joe, you can search google for "Snow Joe Calcium Chloride SDS." This will give you the contents. You want something that is north of 94% purity. Big Box may have them, but easier to find in Ohio because of the snow...not sure about California...

 

[AlexPowell]

As long as CSI is greater than -0.6 you don't need to worry about your calcium level and can let it drift up over time

 

[Bperry]

As long as CSI is greater than -0.6 you don't need to worry about your calcium level and can let it drift up over time

As long as CSI is greater than -0.6 you don't need to worry about your calcium level and can let it drift up over time

Until the CSI reaches 0.0 where you then have to start paying attention to scaling issues if the calcium gets too high.

 

[gaajar35]

Not sure what CSI is. App recommended 24lbs of Calcium Chloride. I added 25lbs of Leslie's Harness Increaser. That increased CH to 325 instead of 250 I was targeting. Separately, noticed that my FC dropped to 2.5 this week. CYA test confirmed it is less than 30. Unclear why it suddenly changed last week. Need to fix that pronto and will bring pool up to SLAM level.

 

[HermanTX]

CYA test confirmed it is less than 30. Unclear why it suddenly changed last week. Need to fix that pronto and will bring pool up to SLAM level.

If you are going to SLAM then only raise CYA to 30 - that way your SLAM level FC is only 12ppm. If you go to 50 then your SLAM level FC needs to be 20ppm. You are just using more LC but you need some level of CYA (i.e 30) to hold the existing FC level at SLAM.
Ensure you test pH before SLAM and have it in the low 7's. Follow the
SLAM Process precisely.

 

[gaajar35]

Good point. What's best way to raise CYA?

 

[HermanTX]

App recommended 24lbs of Calcium Chloride. I added 25lbs of Leslie's Harness Increaser. That increased CH to 325 instead of 250

You should only target 1/2 to 2/3 of the final amount. Because testing and pool volumes are not "perfect" - leave some room for margin of error. After adding the 2/3 amount and letting it circulate for a day, test again and see where you landed. This will help in overshooting targets. This is applicable when adding chemicals to raise, Salt, CH and CYA as these are harder to decrease once they are above your target.

However, a CH of 325 is not terrible. That is where I keep my level at, so you are good to go. Just watch the level of CH if you have hard water as a fill.
t would be best to track CSI. Do you have
PoolMath app? That would do the calculations for you if you enabled CSI to be tracked.

 

[gaajar35]

Actually, looks like I may not need to SLAM - because FC is in the right range - assuming CYA is ~20

 

[HermanTX]

Good point. What's best way to raise CYA?

CYA can only be raised with Stablizer. There are granular products (preferred) or liquid. See my post #74
Are you familiar with the sock method to put granular stabilizer in?

 

[Mdragger88]

Good point. What's best way to raise CYA?

Granular stabilizer via the sock method

CYA - Further Reading

www.troublefreepool.com

 

[HermanTX]

Actually, looks like I may not need to SLAM - because FC is in the right range - assuming CYA is ~20

Assumptions are not good when dealing with chemical testing. If your CYA is below 30 then add sufficient stabilizer to raise it 10 ppm - wait 36-48 hours during which time you need to circulate as stabilizer takes a while to mix thoroughly. Then test again to see if you can confirm CYA of 30

 

[HermanTX]

Actually, looks like I may not need to SLAM - because FC is in the right range - assuming CYA is ~20

I would suggest that once you get CYA up to 30, then do a Overnight Chlorine Loss Test
That will tell you if you have organics in the pool that is eating your FC. This is part of the SLAM process to confirm that you have rid the pool of all organics.

 

[mgtfp]

Not sure what CSI is.

CSI is the Calcite Saturation Index. It tells you how saturated the water is with Calcium and Carbonate. If over-saturated (CSI>0) then Calcium Carbonate can form and create scaling. If under-saturated (CSI<0), the water can pull calcium out of plaster surfaces and grout to reach saturation.

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com