Initial balancing of new (fiberglass) pool

Filipvsb

New member
May 8, 2022
3
Charleston, SC
Pool Size
12500
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Long time reader, first time poster. I’ve learned so much by reading through articles/other threads! New fiberglass pool opened mid July.

I test weekly using a TF-Pro Salt and test ad-hoc using strips. It took a couple weeks to get salt to the right level, figure out how long to run the pump and to what percentage to set the SWG to get to the right chlorine level. Last couple weeks (we had warm weather, heavy rain due to the leftover of hurricane Idalia, we had several parties with groups of people in the pool) the free chlorine is staying steady.

These are my current results:
FC: 3
CC: 0.5
pH: 7.3
TA: 30 > LOW
CH: 125 > LOW
CYA: 0
Salt: 3400

My questions:
  • My TA & CH are low. Should I try to get these withing range? And if so, do I first look at CH or first TA or can I do them at the same time?
  • No CYA has been added to the pool. Do I need CYA if my FC stays good? Are there any other side effects from not having any CYA?
Thanks so much!
 
Without CYA stabilizer in the pool water the sun's rays will burn off your chlorine in less than an hour. Without chlorine in the water at a safe level you risk person to person transmission of disease, among other risks.

Are you running the SWG non-stop, at a higher percentage than normally necessary to compensate for the missing CYA?? If so, you'll shorten the lifespan of the cell enormously.

Why don't you have CYA in the water? 3ppm of FC without CYA must feel very harsh??

Did you fill the pool with city water, or well water? Your TA is low, which may be keeping your pH low, but it isn't ideal.
Do you know about PoolMath yet?

Maddie :flower:
 
Without CYA stabilizer in the pool water the sun's rays will burn off your chlorine in less than an hour. Without chlorine in the water at a safe level you risk person to person transmission of disease, among other risks.

Are you running the SWG non-stop, at a higher percentage than normally necessary to compensate for the missing CYA?? If so, you'll shorten the lifespan of the cell enormously.

Why don't you have CYA in the water? 3ppm of FC without CYA must feel very harsh??

Did you fill the pool with city water, or well water? Your TA is low, which may be keeping your pH low, but it isn't ideal.
Do you know about PoolMath yet?

Maddie :flower:
Thanks for your reply!

1/ I understand CYA protects Chlorine from the sun. Our pool is in full sun all day. My pump runs 10hr/day (4hr@2000rpm 6hr@1100rpm) my SWG is set to 40%.

2/ My pool equipment guy (which I don’t fully trust since he was trying to make it sound very complicated just so he could sell me a weekly maintenance service) said there was no reason to add CYA to the pool if the pool was holding Chlorine. So we never added any CYA. The only thing I can think of is that there is a very low level of CYA in the pool (that my testing is not picking up) due to the fact that we used chlorine tabs for 4 weeks (before the equipment was fully operational - end of June/early July).

3/ Pool was filled with city water

4/ Yes, I do know about the app, and use it! My results should be linked to my profile (but not really sure if everyone can see those).
 
Fiberglass pools do not need CH. Your CH is fine.

Does the pool manufacturer recommend any CH level?
 
You are adding 2.2 ppm FC per day at your settings and pump run time. Your CYA cannot be zero. I also suspect your 'pool guy' is adding some form of chlorine each week. The numbers do not add up.
 
You are adding 2.2 ppm FC per day at your settings and pump run time. Your CYA cannot be zero. I also suspect your 'pool guy' is adding some form of chlorine each week. The numbers do not add up.
Thanks for your reply!

!/ My pool guy hasn't been here in the last 2 weeks. I was always around when he was here and I'm fairly certain of what has been added to the pool (at least over the last 5 weeks). No CYA was added. The only thing I can think of is that we used Chlorine tabs in the beginning (before equipment was done) and in the first couple weeks to get the Chlorine level to the right level, and this left me with some CYA (low - so my tests aren't picking it up)

2/ No heater - so that's not a concern. River Pools (the manufacturer) recommends a CH between 150PPM > 200PPM.

3/ Based on the above replies, and what I read in other threads I think I'm going to do the following:
  • CH is at 125PPM. The manufacturer recommends 150 > 200. I think I'm going to just leave it that for now.
  • I will retest CYA. And very slowly try to raise it until my testing is picking it up (40?)
  • Raise my TA to 60
Any reason against the above approach? Also, if I raise my CYA to 40 - should I also try to raise my FC, or can I try to keep it at 3?

Thanks so much for all the help!
 
Use PoolMath to guide your addition when raising TA.
Fine on the CH plan... over time evaporation will take some water yet leave the calcium behind. So it will rise slowly over time.
Yes,. those pucks probably added some CYA to the water. Taking it up further is a good idea.
You WILL have to increase your Free Chlorine (FC) goal. Use the following chart:
SWG Chart.jpg
 
On the CYA test, does the sample look cloudy at all.
If so, add 20 ppm CYA using PoolMath. That should get you in the 30-40 CYA range.

As long as you are confident in your CYA test, add 20 ppm NOW - don't very slowly add it over time.
Dose FC accordingto the FC/CYA Levels based on CYA 30 or 40. A few extra ppm FC is fine.
 

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