Low Salt Readings

by Monica

I have an above ground pool that is 20X48 & holds 8800 gallons of water. We've had it for 3yrs using regular chlorine/chemicals & last week converted to an Intex salwater system.

We completely emptied the pool & refilled with fresh water. We do not use city/tap water. We have a water well with a notably high lime & calcium content....has always been that way. Initially we added 3 bags of salt, the pump didn't alert us to any problems, but tests showed us 0 chlorine levels. Concerned the pool would grow algae, we shocked it with regular chemicals & finally got a low level of chlorine.

In this past week, the saltwater pump keeps beeping telling us "low salt" when we have now added a total of 9 bags of 40lbs of salt coming to a total of 360lbs of salt. In taking a saltwater reading, it shows we have a level of 4800ppm on the salt.

I am at a point of being in tears because no one knows how to help me. We also now have the regular chlorine tablets in the pool & our chlorine level is reading 2-4...a good level. We cut the saltwater filter off because it just keep beeping "low salt" although the water tastes salty.

What do I do now?

Thanks for the question Monica

First I would recommend you keep a close eye on the salt cell. With the water having a high calcium content, you run the risk of the cell calcifying and burning up. Be sure to keep it clean. You can use a 4:1 mixture of water and muratic acid. Use a soft bristle brush to remove any debris.

I'd encourage you to become familiar with your salt cell. Know the salinity range and try to keep it as close to the middle range as you can. If the salt range is between 3000 - 3500, then keep the salinity 3200 - 3400ppm. Many newer cells have a forgiving range, sometimes between 2000 - 4800ppm.

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper). It makes troubleshooting much easier. You can get this done at your local pool store.

You need to manually test the salinity of the water against the cell reading. This is important but many salt pool owners don't do it. Sometimes the salt cell can give a wrong reading. The tester I used for the YMCA salt pool is a Myron Analog Meter. A picture can be found here:

Salt Water Swimming Pools

There are digital meters that can be used as well. I have always used the company TMI Salt Pure. They're very helpful and can answer your questions. If you choose the Myron meter, you can also get saline water from TMI. It's already at 3000ppm and can be used to calibrate the meter. A titration test that measures chloride is another was to measure "salinity".

Also be sure you're using good food grade salt. You can probably get this kind of salt or something similar at a local feed store. The salt I used is here:

Which Salt To Use In A Salt Water Swimming Pool?

For an average 20,000 gallon pool you will need 7-10 50lb. bags to bring your saline level to the reading of 3000-4000. For 10,00 gallons, simply half that.

With well water, it's important to know about the metals in the water. A metal sequestrant does not remove metal from pool water. It holds it in solution until it can get filtered. Then you backwash the metal out. Because metal sequestrants break down over time and get filtered and backwashed out, you need to weekly dose your pool if you have high iron and copper.

Metal sequestrants that are based on HEDP, phosphonic acid or something similar are the most effective. Jack's Magic Blue, Purple, and Pink Pink Stuff, Metal Magic, Metal Free, & Metal Klear are very good. Get your pool water tested for metals, and all of the other readings as well, to confirm.

Be sure to not put the chlorine tabs in the skimmer. Use a tab float. When the pump turns off, the tabs will continue to dissolve. When the pump turns back on, the system will get a massive dose of acidic water. A tab float is very inexpensive, around $10 - $13 and should last about 3 - 5 years or so.

Without knowing the kind of salt cell you have, I can only guess as to why it's beeping or what code you have for low salt reading. The one we had at the Y had both a front and back electrical board that gave us a reading. We also had a salt sensor that was plumbed into the pipe. If you have something similar to that, be sure to keep that clean as well.

Check the settings on the control box and be sure the system settings are correct. Most systems can be set to run anywhere from 0 to 100% of the time.

The salt cell needs a certain flow rate to read proper salt level and to function properly. Be sure you have enough pressure to push the water through the system. Backwash if needed, be sure the water level is correct (1/3 - 1/2 up from the bottom of the skimmer), and the skimmer and pump baskets are cleaned. Also no debris in the pump motor impeller.

This is for an Aqua Rite salt cell. Your call might be similar.

1-Turn the percentage to 100%

2-Turn the switch to "off" from the Auto position

3-Turn the switch back to Auto

4-Wait a few seconds for the chlorine generating light to come on then press the diagnostic button until you reach the large negative number. Do this as soon as you see the light come one. This should be your salt reading.

5-If the salt reading is 4000ppm or below, turn the switch from Auto to Super Chlorinate then back to Auto. This should reset the salt level to the newsalt reading and allow the unit to make chlorine.

If the salt level is above 4000ppm, the unti might not make chlorine and you may get a zero salt reading. To lower a salt level, you'll need to do a partial drain and refill.

Hope this helps and have a great Summer.


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