Chlorine and salt have dropped off dramatically

Scotland

Active member
Oct 1, 2019
28
Memphis, TN
Cl - 1
Br- 2
pH - 7.5
FC - 1
CC - 0.5
TC - 1.5
CH - 175
TA - 40
CYA - 20
NaCl - 2400

It has rained a lot recently if that could be the cause?

Advice please?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,651
Bedford, TX
S,

If you normally run your FC at 1 and your CYA at 20, I find it hard to believe that you don't have algae already, even if you can't see it.. Algae will consume what little FC the SWCG is making anyway.. The rain diluted the pool water making your FC worse than it was.. and lowered your salt level..

Why are you running your CYA and FC so low??

If this was my pool, the first thing I'd want to do is run an Overnight Chlorine Loss Test.. or Overnight Chlorine Loss Test...

Thanks,

Jim R.
 

Scotland

Active member
Oct 1, 2019
28
Memphis, TN
My previous test on Oct 11th was;

Cl - 5
Br - 10
pH -7.2
FC - 7
CC - 1
TC - 8
CH - 275
TA - 50
CYA - 20
NaCl - 4200

We had been attempting to raise the CYA but being honest, life took over (incl a car crash) and we haven’t put anything in the pool in a couple of weeks.

I read your suggested test and performed it with two differences...the pump was running all night and the sun had just came up (although it is mega cloudy and raining).
All levels stayed as per last night (which was tested after dark).

I can perform it again tonight though too?
 

JamesW

TFP Expert
Mar 2, 2011
16,598
The salt isn't going to go from 4,200 to 2,400 unless you lose a lot of water and replace it with fresh water.

How are you testing?

How much rain did you get?
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,651
Bedford, TX
S,

As long as the SWCG was off, then I would say that you passed the OCLT..

"Life" appears to be the main problem... :)

I would work on getting your numbers back in line with our recommendations.

Your pH is very low for most SWCG pools.. It is not out of range, but most SWCG pools like their pH to be on the high end, like 7.8 or so.. I suspect you are having to use a lot of acid to keep it at 7.2. Also, your CSI is about -1.. We suggest +.3 to -.3. A -1 is corrosive.. If your pH was 7.8 your CSI would be -.44, not perfect, but still ok..

Thanks,

Jim R.
 

JamesW

TFP Expert
Mar 2, 2011
16,598
For the calcium to go from 275 to 175 ppm, you would have to replace 36% of the water.

For the salt to go from 4,200 to 2,400 ppm, you would have to replace 43% of the water.

The CYA stayed the same, but 20 is not a reliable test result and could be 0 to 30 in either case.

Are you adding water to the pool?

Do you have an autofill?
 
Last edited:

Scotland

Active member
Oct 1, 2019
28
Memphis, TN
Sorry.
We have a skimmer leak that we need to get fixed in the spring so we have been adding a lot of water.

We want to get the chemical level right so we can close the pool for the winter.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
You mentioned you already know about a skimmer leak, but you are also about to close correct? So if you're going to wait until spring to repair the skimmer, I would just increase the FC to about 12 (regular bleach) then close/cover right away. You may lose a little water down to the skimmer and it should stop and remain stable once closed. Tackle everything again in the spring.
 

Scotland

Active member
Oct 1, 2019
28
Memphis, TN
Ok, so there is nothing about the levels that could damage the lines etc while it is closed?
I take it I’ll pour in bleach a bit at a time and keep testing? Do I keep the pump running or not?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Your pH is on the low end, but okay. You seem to have a slightly elevated CC level, but I don't think you have much time to mess with that between an OCLT, potential SLAM, and/or closing. Biggest thing right now is trying to close with the best chance of reducing algae at spring opening. Increasing your FC level now to about 10-12 and letting it run for a day or two before losing anymore water to the leaking skimmer and before final closing is about all you can do for now. No real sense wasting time trying to fine-tune other levels for winter. Other than chlorine to prevent algae, the pool will be fine.
 

Scotland

Active member
Oct 1, 2019
28
Memphis, TN
Ok, thank you.

So do I just buy regular bleach and pour it in the pool, testing every now and then?
Is there a guide here to how much bleach? Do I leave the pump on?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Regular bleach is the same as pool chlorine. Just make sure it's no Clorox brand and has nothing listed for splashless or scented. Just plain/regular. Use our PoolMath tool or the APP to determine how much product to add. Pour chlorine/bleach slowly at the return jets with pump on for at least 20 min or so to help mix it around. Test after that to ensure you've reached your target/goal.

More details can be found here: Recommended Pool Chemicals - Trouble Free Pool