Salt level conflicts

[ProspectHill]

Hello.
Since successfully fighting off some black algae my FC levels are still high at 10 but I'm bringing them down by reducing the % on SWG.
I had a test done at the pool place yesterday and the salt reading was 4167.
It's been a little high, over 4000, for a long time. Since I accidentally put in too much salt last winter.
A couple months ago I got a flashing green Salt light which just meant the water level was too low. Added some water and it was fine.

But this morning, the Salt LED is solid red, while the other lights are all solid green.
The diagnostic display says salt is only 2715.
How is that possible?
My FC is still up at 10.
I'm reluctant to add salt to this confusion.
?

Marcia

 

[Jimrahbe]

Marcia,

Having your salt tested by the pool store is not much better than using a guess strip.. You have about a 50/50 chance that they are even close.

Water temp has a great deal with how well the Pentair SWCG's measures the salt level. The lower the temp the less accurate the salt reading is.

Anything below 2800 will turn the salt light red, even thought the cell is still working. Anything below 2600 will shut the cell off.

The Pentair cells use a thermistor inside the flow switch to measure the water temp. When this thermistor goes bad, it can cause the salt reading to be way off.

You really need the ability to measure your own salt level. I suggest that you get a Taylor K-1766 salt test kit.

What specific cell do you have?

How old is it?

Thanks,

Jim R.

 

[ProspectHill]

Pentair iChlo 30, three years old. The flow switch was replaced last fall. The therm switch was replaced last spring.
the water temp has been around 83 (very hot here in USVI).
I could get the Taylor salt test you recommend, but it will take a month to get here.
Should I be doing something meanwhile?

 

[ProspectHill]

Just checked the SWG diagnostics again, it says the water temp is 80 and the salt is 2993.
That's 278 higher than 45 minutes ago.

 

[PoolGate]

What is your calcium (CH) level?

 

[ProspectHill]

it's a little high. 450

 

[Jimrahbe]

Marcia,

The IntelliChlor's salt test accuracy is +/- 500 ppm. I suspect that your iChlor is not much different.. (Edit.. The iChlor is +/- 300 ppm)

Keep in mind that the cell does not continually test for the salt level.. IntelliChlor tests when it starts up and then every 12 hours. I assume your iChlor works about the same way.

Personally, I'd want my cell to be making chlorine, so I'd add a little salt to make the cell happy...

If the cell is covered in scale, it makes it harder for the cell to get an accurate salt reading. So, if you have not looked lately, I'd visually inspect the cell for scale.

Thanks,

Jim R.

 

[Bperry]

it's a little high. 450

Can you see if the plates on the cell are scaled at all?

 

[ProspectHill]

I was just thinking I should check the cell.
more later....

thank you.

 

[ProspectHill]

You called it!

There was plenty of scale build up on the blades.

I acid washed it all away.

now the green light is on and blinking that there's too much salt.
diagnostics says 4600 something....

 

[ProspectHill]

ALSO...

The water level in the pool is fine.

I am going to relax about it for a couple hours.
Then check it again.
You guys are the best.

 

[mknauss]

The SWCG should not scale that badly.
Managing the CSI of the water by adjusting pH and TA with a known CH is needed. That can eliminate the scale buildup to the point it disrupts the SWCG.
Acid cleaning a SWCG removes the rare metals that allow the unit to create chlorine. It is not advisable to use mineral acid (muriatic acid) to clean a SWCG on a regular basis. Best to get cleaning vinegar.

 

[Bperry]

ALSO...

The water level in the pool is fine.

I am going to relax about it for a couple hours.
Then check it again.
You guys are the best.

Be careful about the acid washing. It reduces the lifespan of the cell. I was going to suggest using a popcicle stick, paint stirrer, to get as much out as possible and then try blasting water through it to remove it.

 

[ProspectHill]

Uh oh.

I won’t do that again.
Thank you.

 

[ProspectHill]

Be careful about the acid washing. It reduces the lifespan of the cell. I was going to suggest using a popcicle stick, paint stirrer, to get as much out as possible and then try blasting water through it to remove it.

I did try blasting water through it and tried a stick and a toothpick.
It was hard and not moving

 

[ProspectHill]

Perhaps I could have used more force but the blades look delicate.

 

[ProspectHill]

The SWCG should not scale that badly.
Managing the CSI of the water by adjusting pH and TA with a known CH is needed. That can eliminate the scale buildup to the point it disrupts the SWCG.
Acid cleaning a SWCG removes the rare metals that allow the unit to create chlorine. It is not advisable to use mineral acid (muriatic acid) to clean a SWCG on a regular basis. Best to get cleaning vinegar.

You’re gonna make a water testing, chemical balancing, pool nerd out of me!

I had to look up CSI… but the more I learn the less intimidating this will be.