cloudy water with good number. help please

nabril15

Well-known member
May 22, 2011
340
Miami, FL
#1
good morning
fc 12, ta 80, CH 725, ph 7.8, CYA 40

I don't see algae anywhere, my filter is at good pressure, but the water is hazy; it hasn't rained in a week or so.

EDIT... I was mistaken. I just brushed a decent amount of algae from the deep end and near the light. Darn. Do I need to Slam again?

thank you
 

mknauss

Mod Squad
May 3, 2014
12,202
Laughlin, NV
#2
Your FC of 12. Is that normal or did you raise it? It would be good to get an accurate pH reading but your FC needs to be below 10 for that.

Once our FC reaches 10, test your pH again and if still at 7.8 or higher, try lowering your pH to 7.2 using muriatic acid. Your CSI is quite high with the parameters you show so the pH can easily be lowered.

I would then suggest an tonight.

- - - Updated - - -

Also - with your current CH, you should NOT use Cal Hypo. Only liquid chlorine. You need a large water drain and refill if you wish to use Cal Hypo.
 

nabril15

Well-known member
May 22, 2011
340
Miami, FL
#3
Your FC of 12. Is that normal or did you raise it? It would be good to get an accurate pH reading but your FC needs to be below 10 for that.

Once our FC reaches 10, test your pH again and if still at 7.8 or higher, try lowering your pH to 7.2 using muriatic acid. Your CSI is quite high with the parameters you show so the pH can easily be lowered.

I would then suggest an tonight.

- - - Updated - - -

Also - with your current CH, you should NOT use Cal Hypo. Only liquid chlorine. You need a large water drain and refill if you wish to use Cal Hypo.
Thanks Marty
I added the liquid chlorine and obviously got carried away. I will lower the ph and retest. I do not own the Cal Hypo yet as I have not made the switch. I asked first before doing anything.

EDIT - I just brushed the pool and noticed a decent amount of algae in the deep end and around the light. Another slam? dam.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
4,375
Central California
#4
I will lower the ph and retest.
Perhaps just a typo? You need to lower the FC, to 10 or lower, then retest the pH, then set the pH to 7.2, as part of your next SLAM. You shouldn't move your pH until you can test for it properly, which you can't do while FC is above 10. Yes, you must SLAM, sam! ;)
 

nabril15

Well-known member
May 22, 2011
340
Miami, FL
#5
Perhaps just a typo? You need to lower the FC, to 10 or lower, then retest the pH, then set the pH to 7.2, as part of your next SLAM. You shouldn't move your pH until you can test for it properly, which you can't do while FC is above 10. Yes, you must SLAM, sam! ;)
how do I lower the FC not draining?

So I need to lower the FC, then test and lower ph if necessary, and then add a bunch of FC???
That sounds contradictory.

EDIT - I just thought about a way to lower FC - don't add any, and let it evaporate slowly.
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
#6
Give the pool a good brushing to expose all the algae to the chlorine. Your FC will be under 10ppm in no time.

Once you get pH to 7.2 go straight to SLAM.
 

nabril15

Well-known member
May 22, 2011
340
Miami, FL
#7
Give the pool a good brushing to expose all the algae to the chlorine. Your FC will be under 10ppm in no time.

Once you get pH to 7.2 go straight to SLAM.

Educate me please.
Why is it important to lower the ph before starting a slam? I didn't find an answer anywhere. I know that it has to be done but not the reason.
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
4,375
Central California
#8
Well, that's a good question. I know why in my pool. My pH tends to rise, every day (most pools do, to some degree). If I started a SLAM while it was highish, like 8.0, and the SLAM lasted for several days or weeks, my pH would rise beyond acceptable levels way before the SLAM was over, but I wouldn't know where it was, to move it back down, because I wouldn't be able to test for it during a SLAM (because the SLAM-elevated FC would interfere with the pH test).

By lowering it to 7.2 before the SLAM, then it can rise for quite a while before it goes out of range, so I wouldn't have to worry about it during a SLAM.

It does sound contradictory to lower FC, only to raise it again later, but lowering the FC is the only way to get an accurate pH reading. Then you have to raise it again, back up to SLAM levels. That's why you must adjust your pH down before you start your SLAM, to avoid that yo-yoing.

There may or may not be a other reasons for lowering pH, we'll have to let others chime in about that.

And yes, the easiest way to lower FC is to just let the sun, bather load and/or algae use it up. In other words, do nothing.
 

mknauss

Mod Squad
May 3, 2014
12,202
Laughlin, NV
#9
The main reason we recommend you lower your pH to 7.2 prior to SLAM is that you cannot accurately test pH when the FC is above 10 ppm which it will be all the time during a properly run SLAM. The secondary reason is that the chlorine is marginally more effective at lower level of pH.
 

domct203

Bronze Supporter
LifeTime Supporter
TFP Guide
Jun 3, 2015
3,959
CT
#10
Educate me please.
Why is it important to lower the ph before starting a slam? I didn't find an answer anywhere. I know that it has to be done but not the reason.
As mentioned in the thread, it’s because you cannot accurately measure the pH during the SLAM.

This is also stated in the prerequisites of the SLAM procedure.

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Leebo

Admin
TFP Expert
LifeTime Supporter
Jul 21, 2011
7,956
Eastern Ohio
#11
If I may push the thread back to the original question................

EDIT... I was mistaken. I just brushed a decent amount of algae from the deep end and near the light. Darn. Do I need to Slam again?
The answer here is a simple yes, another SLAM is needed. If you're seeing algae as you brush then something has occurred that is needing another SLAM. Add enough acid to get your pH down and bump your FC level up to 16 to start the SLAM. I wouldn't worry about lowering your FC any to retest your pH as it's already likely lower than 10 (as the algae consumes the chlorine).
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,321
Sebring, Florida
#12
+1 what leebo said. Stay focused on SLAMing your pool. Once SLAM is complete, you will have to change how you chlorinate so the algae will not return. Algae returned because the maintenance chlorine was inadequate. Be sure to brush your pool regularly.
 

nabril15

Well-known member
May 22, 2011
340
Miami, FL
#13
+1 what leebo said. Stay focused on SLAMing your pool. Once SLAM is complete, you will have to change how you chlorinate so the algae will not return. Algae returned because the maintenance chlorine was inadequate. Be sure to brush your pool regularly.
Thank you Dave. I slammed recently (a month or 2) and obviously didn't maintain properly. My wife will usually brush the steps and spa bench cotner when she sees it greenish, but we rarely brush the rest of the pool-lesson learned.
If I may push the thread back to the original question................

The answer here is a simple yes, another SLAM is needed. If you're seeing algae as you brush then something has occurred that is needing another SLAM. Add enough acid to get your pH down and bump your FC level up to 16 to start the SLAM. I wouldn't worry about lowering your FC any to retest your pH as it's already likely lower than 10 (as the algae consumes the chlorine).
Thank you leebo and all.
Oclt=0 strangely, but I still brushed a bit of algae this morning and the pool remains hazy. I cleaned the relatively clean filter and won't add more chlorine since I am at the slam level.