Strange Salt Level Readings

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Re: Strange

Just ran another set of tests.

SWCG states 2700 PPM at 55 degrees
Strips state 3070 at 70 degrees (let the test water warm up)
Drop test states 5400 at 70 degrees. I used my Speed Stir and added one drop at a time, slowly, until the color changed from milky yellow to milky pink/salmon. No additional drops were added.

FAS/DPD FC test shows 2.5
ph 7.5
TA 70
CH 260
Borates 40
CYA 40

This was after running the pump and robot today for 2 hours. What amazes me is how wildly different the drop test is. I am somewhat inclined to believe the drop test, as it more closely fits what I've added, considering poolcalculator says it should take 50 bags to get to that amount, but I've only added 35. I say I am inclined to believe it because there may have already been salts in the pool from chlorine usage. But, that's sure a high reading.

Either way, I'm still confused. And not adding more salt for sure. ;)
 
Re: Strange

Are you sure they gave you the correct cell size? If the cell was half as big as it should be, the unit would think the salt level was half of what it should be because the amps would be half as much. Perhaps they mislabled as CPCS24 as a CPCS48.
 
Re: Strange

The SWG is probably going to be off due to the water temperature. The cell is most likely calibrated at 77 oF. For every 5 degrees below that, the salt will read 200 ppm low. At 55 F the salt will probably read about 880 ppm low. 880 + 2700 ppm is 3580 ppm. There will be some inconsistency from test to test. That's why I always like to test salt in multiple ways to compare and contrast the readings.

You could take a sample in to a pool store to have them test with their meter. You could get some calibration solution to verify their meter's accuracy. You could make your own calibration solution by adding exactly 3.2 grams of salt to 1 liter of distilled water.

What is the salt level of your fill water?
 
Re: Strange

RobbieH said:
Yes, I have turned on the SWCG long enough to get a reading, see above, it's showing higher salt after adding the additional 200 lbs, but the strips are not. And note I let the test water warm up before testing with strips.
Click to expand...
He turned on the cell in order to read the salt level. But are you certain the CompuPool does not not compensate the salt readout for temperature? If it doesn't, then that would explain the difference.
 
Re: Strange

I don't think that the Compupool has temperature compensation, but I'm not sure. Someone could contact the manufacturer to inquire.

My best guess would be that the salt is somewhere between 4,000 and 5,000 ppm. I would have the water tested by a meter. And, I would verify the meter's accuracy with a known calibrated solution.
 
Re: Strange

How about the difference between the strips and the K-1766?

I can't run anymore tests for a while. I had all the tile decking around the pool taken off, concrete cut out, and all newly rebedded and mortared (SP?). The pool water is a complete mess right now. Probably take another couple of days with the pump/filter and robot to get it cleared.
 

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Re: Strange

I believe they use the same power supply for the different models. They do have a calibration procedure for the different cells. I think if you call them they will email it to you. The CPSC does not do any type of temperature calibration. The display of the salt result on the CPSC has a 10% variance. There is also a note that sates salt results can vary depending on water current and water temperature.

What's your FC level measuring at? What's your % output and run time? If it's climbing, decrease % or run time. If it's falling falling increase % or run time.

Low salt will cause two lights Water fault and Add salt Add salt will come on when it falls below acceptable levels. On page 8 of the manual it states minimum salt level is 3000 ppm, up to 6000 ppm, ideal level is 3500.
 
Re: Strange

I know the thread has gotten too long to read it all, but that's all here.
FC is 4
SWCG is off (no output) since FC is holding. No need to run it.

I understand how to adjust it, and I know what the proper salt level is. I'm trying to get an accurate reading of what my salt content is. I'm getting wildly different results, and strange results based on how much salt I have put into my pool.

Water Fault does not come on when there's low salt. In the manual on page 6 it states this light comes on when water is not flowing. :) Right now mine will occasionally say Low Salt when the CompuPool thinks it is below 2500 ppm. I have not seen a Water Fault light.

My manual only states the ideal salt level is 3500.
http://www.compupoolproducts.com/pdf/CP ... merica.pdf

It's not the perfect manual. In one case it says:
Do not let Chlorine Stabilizer drop below 3000 PPM.
I don't think I want my CYA at 3000.
 
Re: Strange

Hmm. The manual I received in the kit isn't as nice as the one they have online, but it was also the newer model. I believe in current production models the replaced the fuse on the bottom with a resettable breaker.
9.3.3 Water Fault. Severe low salt conditions will also activate the "Water Fault" warning light.

(If you're interested I can scan and send the manual I got. It's 21 pages) Trying to help, not trying to confuse or put out bad info.
 
Re: Strange

Strange. (again!) In the printed manual I got it says it will work up to sea water, but at high concentrations it can cause corrosion or damage to pool equipment. I'm just trying to get to 3500 but can't get any accurate readings. I've put more salt into my pool than should be needed for my 44,000 gallon pool, and that's not even including what salt was in there before I started.

I shouldn't have any severe low salt issues.

Hm, mine has a fuse still.
 
Re: Strange

I wouldn't sweat it and it doesn't sound like it's a problem. That's why there's a range on the salt content. I spoke to John at compupool in Florida. He was very helpful when I had an issue/questions. I'll post some updated pictures of my setup.
 
Re: Strange

Back to this thread, the test results are still all over everywhere.

Compupool says 3400
Strips say 2610
Drops say 6400

FC 9 (SWCG was too high while I was traveling last week)
pH 7.4
CYA 80
Water temp 74

I still don't know which numbers to trust.
 

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