SWG fixed. Pool Shocked. What's Next?

[LynnOnTheWeb]

My shock is complete, my pool is holding chlorine overnight, and we've got sparklage.

Now it is time for fine tuning. Here are my latest readings.

FC 4.25
CC .5
TC 4.75
PH 7.8
TA 100
CH 200-210
CYA 30

What's my next step? Add stablizer to get PH down and CYA up then test everything again next week? Or, do I try to make other changes like adding calcium chloride at the same time?

Thanks,

Lynn

 

[woodyp]

You should match your CYA level with what your SWG requires, usally 60 to 80.

 

[JamesW]

What type of pool do you have, concrete, fiberglass or vinyl liner?

 

[jblizzle]

I would just get the CYA dissolving with a target of around 60-70ppm and that will also result in lowering the pH some.

 

[LynnOnTheWeb]

It's plaster (I think technically it's PebbleTec or PebbleSheen or PebbleSomething).

Okay, raising CYA will be my next step.

The manual states:

Chlorine stabilizer should be maintained between 50 - 75 PPM. With high water temperatures above 30°C,stabilizer (cyanuric acid) must be kept at levelsfrom 75 - 85 PPM.

I'm guessing that means I'm going for 75 since my water temp is currently at 93? Or Jason, should I just target 60-70 right now like you mentioned.

 

[jblizzle]

With the large change, it is usually good to do the adjustment in 2 steps. The reason I suggested 60-70ppm is so that you would not overshoot too high and then could do another smaller bump up in a week.

 

[LynnOnTheWeb]

Makes sense. I'll try that and retest next weekend. Thanks for the advice.

 

[duraleigh]

+1 what jblizzle said about moving CYA in increments. :lol:

 

[JamesW]

do I try to make other changes like adding calcium chloride at the same time?

Regarding calcium: Based on your current numbers, your water is balanced, and you should not add calcium at this time.

If your pH, TA and/or temperature come down and/or your CYA goes up, you can increase the Calcium Hardness a little, but it's important not to overshoot, as that could lead to scaling.

Also, I would suggest keeping your salt level at the lower end of the range due to the high water temperature, which can cause the salt system to produce excessive current, especially if it's plumbed in-line after a heater.

Note: Most people can follow the general guidelines for water chemistry with good results. However, a heated plaster pool with a SWG can be a challenge. In your case, watching the CSI using the pool calculator can be helpful.

calc.html

 

[LynnOnTheWeb]

James,

Thanks for the additional info. Now you're blowing my mind!

Regarding calcium: Based on your current numbers, your water is balanced, and you should not add calcium at this time.

According to the recommendations here pool-school/water_balance_saltwater_generator I should have a CH of 250 but I'm only at 200. You're saying no need to adjust?

watching the CSI using the pool calculator can be helpful.

I checked my CSI in the Pool Calculator. Looks like I'm at .31 and the calculator puts me at .2 (and in balance, like you said). So, are you saying, make this the indicator of where I should be and, assuming that that number is in range and my chlorine and CYA is good, I should leave the other numbers/levels mostly alone?

What challenges should I anticipate because of my combination of heat/PebbleTec? Algae or just balance in general?

Thanks for the additional info. This is complicated stuff but I'm actually enjoying learning about it!

 

[JamesW]

Using:
pH: 7.8
TA: 100
Calcium 210
CYA: 30
Salt 3200
Borate: 0
Temp: 93 F

I get a CSI of 0.09, which is in balance. Most people can use the general guidelines with good results. However, there are a few cases where the guidelines don't fit exactly, and one can benefit from a more exact match to their individual situation. Right now, your temperature is higher than average, your CYA is lower than the guidelines and your TA is higher than the guidelines.

You will probably need to get the TA down to about 60 to get the pH to stabilize. Once you get your TA down, and your CYA up, then you can add the calcium.

Calcium in a plaster pool helps protect the plaster from deteriorating, but you don't want to get it too high or you risk scaling, especially in a salt cell or heater. Typically, you should be OK with a CSI between -0.3 and + 0.3. However, I would aim for -0.2 to 0.0.

 

[jblizzle]

My CH was around 120ppm when I replaced a lot of water ... there was no way I was going to intentionally raise it when I know that the evaporation here is going to raise it quickly anyway. So, I did as James is saying by keeping the pH a little higher, I was able to keep a reasonable CSI.

I am up to 200ppm now after about 3 months.

These recommendations are quite a bit more advanced as things like CSI are too confusing to people new to the pool chemistry.

 

[JamesW]

LynnOnTheWeb

I probably went into too much detail explaining why you should wait to add the calcium. I hope that it did not cause you any confusion.

Pretty much, the guidelines will work for you, and the main point I should have focused on was to wait on balancing the calcium until the other parameters were in line.

 

[LynnOnTheWeb]

I appreciate the extra info, even if it is a little overwhelming. Personality-wise, I'm a data collector, meaning that I read and read and read and read everything about a topic when I'm trying to learn about it. Even if I don't fully understand the entire picture right now, I will. At some point and this conversation will probably serve as an ah-ha moment.