Aquarite Reporting Low Salt

[bluenoise]

Well, I'm still having a problem with my Aquarite SWG and I'm hoping I can get some help here.
I fixed the leak described above and my pool is holding a salt level of approximately 3100, according to the test strips. The water looks and feels fantastic, but testing the chlorine tells me I'm lower than I would like to be. Also, the Aquarite's reading of the salt level drifts down over the course of a week or two such that it starts reporting low salt. Recalibrating restores a much better reading of 3000-3100, which is nearly spot-on with the test strips.

Last Summer, I was running it at about 15-20% to maintain a chlorine level of about 5-7 ppm. This Summer, it's running at 40% and keeping a level of about 1.5 ppm (as confirmed by both the DPD and the OTO tests). I looked at the cell and it looks clean, save a little bit of dust-like stuff on some of the plastic parts inside. I blasted some clean water through it using a small brass nozzle on my garden hose, but the dust didn't seem affected.

I reinstalled the cell and took a sample of water from the nearest return while the SWG was running (the fine bubbles tell me it was generating at that time). That water had a chlorine level of 1.5 ppm, which I expected to be much, much higher.

My other numbers are pretty good:

FC: 1.5
CC: 0
Ph: 7.6
TA: 110
CYA: 65
Temp: 85F

This cell is only about a year old and nothing has changed in my setup since installation last year.

 

[dschlic1]

You probably have a low level organic infesttion. It is possible, with a SWCG, to have something growing in your pool (usually algae) and still maintain a chlorine level. The only indication is a higher than normal setting on the SWCG.

Becaise of this I recommend a good hard shock for your pool. Also when shocking besure to brush all pool surfaces and circulate pool water through all piping. I had a similiar recurring problem, and it was because I hadn't circulated pool water through some air piping that was connected to therapy jets on my pool.

 

[bluenoise]

Interesting. Would that cause the water returning to the pool from the cell to have such a low chlorine level, too?

 

[bluenoise]

I spoke with a tech at Goldline and he told me my CYA was too low and that I need to test for phosphates. I don't have a way to test for that, but would that cause the symptoms I have? Also, he said the water coming from the returns won't be any more chlorinated than the general pool water when the SWG is running as it doses chlorine in too small of quantities to measure. I thought that was a little strange as the water was supposedly getting shocked in the cell.

Today, I have 2.0 FC and 1.0 CC, so I'm going to shock with chlorine to carry me through the weekend.

 

[dschlic1]

With a CC level of 1.0 you definately need to shock the pool.

If you know the flow rate of your pump you can calculate what the FC of the discharge should be. You probably have the T-15 cell which produces 1.45 lbs of chlorine per day. this is 0.001001 lbs of chlorine per minute. Water weighs about 8.34 lbs per gallon.

 

[JasonLion]

A SWG should raise the FC level of the water passing through it by at least somewhere around 2 ppm when it is on, possibly more, even much more. With a FAS-DPD chlorine test it should be simple to measure, but only if you can get a water sample that really is coming directly from the SWG. Only a very small portion of the water passing through the cell gets raised to shock level.

It is very unlikely that phosphates have anything to do with your current problems.

While it wouldn't hurt to raise your CYA level a little, it isn't low enough to be causing any problems.

Shocking would be a very good idea. Algae could explain some of what is happening, either as a primary or secondary issue.

 

[bluenoise]

I have successfully shocked the pool. It is currently maintaining an FC of about 11 ppm and CC of 0.0 (with the aid of bleach). I shocked to about 16 and it held over the course of two days last weekend. I also cleaned the filter Monday evening, so things are flowing nicely. I cleaned the cell with the acid solution as directed by the owners' manual. Looking through it, I see no debris or buildup of any sort. It looks brand new inside.

My problem persists. I can recalibrate the SWG and it very closely matches the salt level as indicated by the test strips (~3100 ppm). But after a day or two, it's reporting <2600 and, if I let it go too long, it stops producing chlorine due to low salt. When it's generating, there are fine bubbles at the returns, but my chlorine level just can't keep up. What current and voltage levels are normal in the diagnostic display? I forgot to note the readings back when everything was joyous.

Also, here's a funny pool store story: I was at Leslie's to buy some acid and I asked about my SWG's problem. They can do a test on the cell there, but I'd have to leave it for the day. The gal asked me why I thought something was wrong. I told her that I was able to keep it running about 20% duty cycle last Summer, but this Summer has it not keeping up even at 60%. She said, "Oh yeah, you should be running closer to 85-90% on it. That's what I tell all my customers this Summer." Puzzled, I asked, "How do you know what my pool needs if you don't even know how much water it holds?" She just gave me a blank stare and then said, "It has nothing to do with the size of your pool." Hehehe.

 

[bluenoise]

My Aquarite is requiring calibration every other day to keep operating. I called Goldline last week to ask, yet again, about what I can do to make it work properly. I called when the display was indicating low salt so the tech could (hopefully) diagnose the problem as it was happening.

When the tech answered, I told him what it was doing (reporting low salt in spite of it being about 3200 ppm). The first thing he told me to do was calibrate it and he described the exact steps I have been taking every two days already. Before doing it, I said I was hoping he could work with me before I reset all the data. He again told me to calibrate and THEN he can help me. After completing the calibration, he tells me, "It sounds like all your numbers are fine, now." I told him that's what I was trying to explain to him and he then told me to "call back if it's doing it again."

I am at my wit's end with this stupid problem. He told me I'd be charged a service call if a tech came out and saw the same thing (good numbers) as he saw after calibration. While I don't mind having a tech come out, I would expect it all to be covered under warranty. But what should I expect if a tech comes out and does the calibrate with the same results? Everything is great right after I calibrate, but a few hours later, the readings are low.

Right after calibration, it reads 3000-3200 (perfect!)
After seven hours of running: 2800 (hmm)
Next morning at pump start and after startup delay: 2800 (expected)
After seven hours of running again: 2600 (shut down with "Low Salt" indicator flashing)
Right after recalibration again: 3000-3200.

Nothing has changed in my plumbing or setup since last Summer when it was installed and working perfectly.

 

[Poolsean]

Aquarite units used to "guesstimate" the salt level by the amps and volts of the cell ...(I thought I heard that it's got a dedicated salt sensor now, but I don't know if this is true). What this means is that since the amps and volts can be affected by water temperature, salt level, and condition of the cell, you can't really do anything about water temperature (unless you have a heater), your salt is good at 3500 ppm, and the other is the cell condition.
Since the Leslies store offered to test it, I recommend taking it in and testing it. Although it is 10 months old, you never know.

Usually during cold water temperature conditions, I recommend increasing your salt level to the upper end of the acceptable salt range, so that the increased salt can compensation for the decreased conductivity of the colder water.

 

[bluenoise]

Hi, Sean-

Thank you for the reply. I did have Leslie's take a look at the cell a week ago and they said, "It's making chlorine and looks fine," but the tech also mentioned their test doesn't quantify it beyond that.

I think my Aquarite determines salt level as you described based on temperature, current, and voltage. My water is around 75-80 this past week, depending on time of day.

Here is something that crossed my mind: When the booster pump for the Polaris turns on, it steals some of the flow from the post-filter, pre-SWG flow. I see the SWG's current level drop by 0.5 amps when it comes on. The tech at Goldline tells me that it's still well within the acceptable range of values and that the flow switch is calibrated to stop the SWG if there is insufficient flow, so he didn't think it was part of the problem. Also, this setup hasn't changed since the original installation of the SWG, so this shouldn't make a difference. Still, I think I'll disable the cleaner for the next few days to see if that changes the symptoms at all.