Always low chlorine

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Last year we added a salt system after resurfacing our pool. We have the Pentair intellichlore system. Firs 8-10 months, salt easily adjusted using plus minus buttons. I noticed over the past 4 months or so I have to have it maxed and do a boost twice a week to barely hit the levels I need. I cleaned it thinking that would help but no change. All lights are green and I am at 3750 ppm per test strips. Green lights always flashing in succession and the all together under boost cycle. Thoughts?9DC6F2E9-9676-4116-B328-CE012718085F.jpeg
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,005
Bedford, TX
Terry,

My thought is that you did not give us near enough info...

What size cell? (IC20, 40 or 60)
How big (in gallons) is your pool?
How long do you run your pump?
What is your CYA level?
What FC level are you shooting for?
Is your water green or cloudy?
Have you recently had an algae bloom?

I suspect that you have an algae bloom even if you can't see it.. A SWCG cannot produce enough chlorine to compensate. But, no way to tell without the above info..

Thanks,

Jim R.
 
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BTERRY1

Active member
Jul 27, 2019
27
San Diego
Jim. Here are some additional details.

17000 gallons
IC40
2hrs at 3150 rpms and 6 hrs at 2100 rpms
No visible algae bloom
Water crystal clear
Minor algae in small areas about every 2 weeks
Total hardness 500 ppm
TC 1
FC 1
PH 7.6
TA 80
CYA 80

Chlorine at 1 even after 24 hour boost
Salt 3750 ppm

Let me know what you think
 

atx

Member
Sep 3, 2014
7
DFW, TX
Did you use a Taylor kit or tf100 for those results? Advice requires results from those kits, not strips. Retest the cya being sure to follow Taylor's instructions.

Minor algae in spots means an algae problem, please follow slam procedure per the tfp procedure, no shortcuts. Good luck!
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,005
Bedford, TX
Terry,

If you have any algae you can see, that means you have plenty of algae you can't see.. Any chlorine that your cell produces will get consumed by the algae..

Your cell, in your pool, should produce .41 ppm of FC per hour.. if run at 100% output.. So, in 8 hours it can only produce 3.3 ppm of FC.

Most pools in the summer use 2 to 4 ppm a day with the average being 3 ppm.. So unless you are running at 100%, your cell will have a hard time keeping up..

Logic says, that either the cell is not working, or something in the water is consuming the chlorine.. Since you have, or have recently had, some algae, that would be the first thing to test.

I suggest that you perform an Overnight Chlorine Loss Test (OCLT).. This is how.. Overnight Chlorine Loss Test

Basically, after sundown, use Liquid Chlorine and bring your FC up to above 8 or so.. Then get your rear out of bed before sunrise, and test again.. :) If you lose more than 1 ppm of FC then it means algae is consuming your FC. The only problem with this test is that you need to use a pretty accurate test kit.

Try that and let us know how it works out.

Thanks,

Jim R.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Terry,

If you have any algae you can see, that means you have plenty of algae you can't see.. Any chlorine that your cell produces will get consumed by the algae..

Your cell, in your pool, should produce .41 ppm of FC per hour.. if run at 100% output.. So, in 8 hours it can only produce 3.3 ppm of FC.

Most pools in the summer use 2 to 4 ppm a day with the average being 3 ppm.. So unless you are running at 100%, your cell will have a hard time keeping up..

Logic says, that either the cell is not working, or something in the water is consuming the chlorine.. Since you have, or have recently had, some algae, that would be the first thing to test.

I suggest that you perform an Overnight Chlorine Loss Test (OCLT).. This is how.. Overnight Chlorine Loss Test

Basically, after sundown, use Liquid Chlorine and bring your FC up to above 8 or so.. Then get your rear out of bed before sunrise, and test again.. :) If you lose more than 1 ppm of FC then it means algae is consuming your FC. The only problem with this test is that you need to use a pretty accurate test kit.

Try that and let us know how it works out.

Thanks,

Jim R.

will this kit be sufficient for everything i need to do? i could grab one on my way home this evening.
Taylor Technologies K-1004 - DPD Deluxe Test Kit

also, what is the best way to bring my chlorine up to that level? can liquid chlorine be added to a salt system pool?
 

IceShadow

Gold Supporter
Jun 8, 2019
1,063
Milwaukee, WI
That test will only go up to 5ppm of FC. If you do need to SLAM, you will need to get to 31ppm of chlorine and maintain it there. You need to get an FAS/DPD test. I highly recommend this one, with the XL option, to make sure you don't run out of reagents during a SLAM: TF-100 Test Kit ™

Liquid chlorine is the best way to raise your FC as it will only add salt. Other methods will add CYA or calcium to the pool. A salt system pool is a chlorine pool - it just uses a salt cell to generate chlroine from the salt in the pool. But if it needs a boost, liquid chlorine is the way to go.
 

Msch99

Gold Supporter
Bronze Supporter
Jun 11, 2018
369
Verona, MO
You really should have the tf100 or the k2006c kits to test properly and before the experts here can help.

Yes you can add bleach to a swg pool. Plain unscented. Walmart usually has the 10% pool bleach.

Also add your pool equipment to your signature. It helps the experts and saves you time not typing in each post. Settings then signature I think.
Add CL asap to get to 5ppm and keep it there until you get a proper kit. Link to tf 100 in my signature.

If you are on phone or tablet, turn sideways to see sig.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,005
Bedford, TX
Terry,

No, it is a color comparison type of test, where you kind of hope you have the right color..

You need an FAS -DPD test, which is a color change test kit.. Basically you add reagent that turns the test water pink and then add drops of another reagent, each drop is equal to either .2 ppm or .5 ppm. You count the drops until the pink color turns clear, (no guessing). This test give you a pretty accurate FC level..

Here is a link about test kits..Test Kits Compared

I use the TF-100, which includes test for FC, CC, pH, TA, CH, and CYA..

For the OCLT you only need the FAS-DPD... Warning!!! Once you get hooked on testing your own pool water, it will not be enough.. :mrgreen:

Just to be clear.. A saltwater pool is a chlorine pool... The SWCG is just making chlorine... and chlorine is chlorine, no matter where is came from.

Thanks,

Jim R.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Terry,

No, it is a color comparison type of test, where you kind of hope you have the right color..

You need an FAS -DPD test, which is a color change test kit.. Basically you add reagent that turns the test water pink and then add drops of another reagent, each drop is equal to either .2 ppm or .5 ppm. You count the drops until the pink color turns clear, (no guessing). This test give you a pretty accurate FC level..

Here is a link about test kits..Test Kits Compared

I use the TF-100, which includes test for FC, CC, pH, TA, CH, and CYA..

For the OCLT you only need the FAS-DPD... Warning!!! Once you get hooked on testing your own pool water, it will not be enough.. :mrgreen:

Just to be clear.. A saltwater pool is a chlorine pool... The SWCG is just making chlorine... and chlorine is chlorine, no matter where is came from.

Thanks,

Jim R.
thanks everyone so far for your help. As you can tell i am a definite newbie. I will pick up the appropriate test kits and am reading like mad on this forums Pool School etc. I did find a calculator online to help me determine how much chlorine in need to start adding to SLAM. at 17000 gallons and needing to go from 1ppm to 31ppm it says 5 gallons. can this bee added all at once when i am ready to start the process? how much additional should i get since it sounds like this could on for days with me continuing to have to add to keep the levels there? also just watched the video. so once i pass the final test and loos no FC overnight. how do i get the FC levels back down to the appropriate level?
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
i was able to get the 2006C for a thursday delivery. i will start testing that night and report back on friday to drill in with greater details. thank you all.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,005
Bedford, TX
Terry,

Technically, you should do a SLAM any time you see algae, but with a CYA of 80 it makes it much harder.. I suggest you run the OCLT first and then we can decide on SLAMing..

Thanks,

Jim R.
 

cavey00

Member
May 6, 2019
9
Las Vegas
Not a SWG expert but I would imagine that if you turn the generator down low, the sun should consume the chlorine and bring it down to the appropriate level.
 

IceShadow

Gold Supporter
Jun 8, 2019
1,063
Milwaukee, WI
Terry,

Technically, you should do a SLAM any time you see algae, but with a CYA of 80 it makes it much harder.. I suggest you run the OCLT first and then we can decide on SLAMing..

Thanks,

Jim R.
This - just add enough to take it up to about 10ppm when you get your test kit, after sundown. Turn off the SWG cell first. After 30 mins of the pump running/pool circulating, test the actual FC level with the FAS/DPD dropper kit, to confirm it's 10 - if it's not, no problem, just note what it is. Then get up in the morning and test again, making sure the SWG was off all night. With no sun hitting the pool, if any chlorine is being consumed (more than 1ppm, as that is the accuracy level of the test), then you have algae and should proceed to SLAM.

No need to have the SWG cell running during a SLAM - the FC it creates will be pretty minimal compared to the liquid chlorine you'll have to add, so you might as well save the life of the cell.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Terry,

Technically, you should do a SLAM any time you see algae, but with a CYA of 80 it makes it much harder.. I suggest you run the OCLT first and then we can decide on SLAMing..

Thanks,

Jim R.
thanks, this will be the first thing i do on thursday night after my test kit arrives.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
This - just add enough to take it up to about 10ppm when you get your test kit, after sundown. Turn off the SWG cell first. After 30 mins of the pump running/pool circulating, test the actual FC level with the FAS/DPD dropper kit, to confirm it's 10 - if it's not, no problem, just note what it is. Then get up in the morning and test again, making sure the SWG was off all night. With no sun hitting the pool, if any chlorine is being consumed (more than 1ppm, as that is the accuracy level of the test), then you have algae and should proceed to SLAM.

No need to have the SWG cell running during a SLAM - the FC it creates will be pretty minimal compared to the liquid chlorine you'll have to add, so you might as well save the life of the cell.
to confirm, the pump runs all night while performing the OCLT
 

IceShadow

Gold Supporter
Jun 8, 2019
1,063
Milwaukee, WI
It doesn't have to, but it can. You do want it running 30 minutes after adding chems and 30 minutes before testing, so unless you want to get up 30 mins before you test (which is before sunrise) I'd let it go all night. :) Plus then it mixes the water as you sleep and makes sure that the test you get is uniform.
 

BTERRY1

Active member
Jul 27, 2019
27
San Diego
Test kit came early. Today free chlorine is 4ppm and total chlorine shows as 0. Is that possible? PH high at 8. Should I lower the ph and test again in three hours before I do my overnight chlorine test?