Can Salt Concentration Go up?

[DanF]

I have been testing my salt content monthly with my K-1766, and until a few months ago it's been pretty stable at 3800 ppm. I have a Circupool RJ45+ so this is right where I want to be.

Lately however it's been creeping up. I tested it today, after having been away for 2 weeks, and it's at 4200. The Circupool's controller was flashing "high salt" but only intermittently. It's readout showed an average salinity of 4000 and a real-time of 4125.

1. How would my salt levels increase? We've gotten more rain than normal lately, so I would think if anything salt would be lower.
2. Should I be concerned and if so should the proper action be to drain some water?

Thanks...

 

[Newdude]

For one, the test is accurate to +\- 200 ppm. So if it was really 4K this whole time, both # readings are considered accurate.

or one/several of your drops was off.

or another adds like Liquid chlorine added the salt.

if it’s reading high salt you need to drain no matter what your tests say. You can’t talk sense to the unit and have to follow what it says. You have all but proven it’s not defective with the K-1766 kinda agreeing.

 

[mknauss]

How would my salt levels increase? We've gotten more rain than normal lately, so I would think if anything salt would be lower.

Adding muriatic acid, fill water, etc, all add salt.
I doubt you had overflow due to rain. It may have slowed your fill water needs, but not eliminated them.

 

[Newdude]

Pro tip: Target the lower side of the range and not the high side (figuring you’ll lose some with rain). It’s very easy and cheap to add salt if the unit says you went too low. It’s difficult to remove if the unit says it’s too high.

 

[DanF]

Thanks @mknauss and @Newdude. Never was aware that fill water and MA added salt. Note: I haven't added LC since installing the SWG last fall.

PoolMath says drain 12% of my water to hit 3700. Although I have a pebble-tec pool, which is supposed to be immune to draining in the summer here in the desert, I am not sure I want to. But maybe 12% or so wouldn't be a problem? I guess I could always do a simultaneous drain and fill, but I have never done that before -- always drained in the winter.

In another week I'll be away for 2 weeks so I'm reluctant to do nothing.

 

[Newdude]

But maybe 12% or so wouldn't be a problem?

Let’s let @mknauss agree/didagree here first, but you wouldn’t be exposing all that much surface to the sun if you drained, say this weekend when you were around. You could hose down the exposed parts every half hour or so while it is low and the sun is high. If you timed it right and drained late afternoon you could fill overnight and be good by late morning with minimal wetting needed.

 

[mknauss]

If another good size monsoon storm is predicted lower the pool by a few inches and use the rain and some fill water to make it up.

I do not think your SWCG actually stops producing chlorine until much higher salinities, but check your manual.

 

[Newdude]

Marty what do you think about my idea to water the exposed shell if needed ? I only know what y’all have taught me about plaster.

 

[mknauss]

Marty what do you think about my idea to water the exposed shell if needed ? I only know what y’all have taught me about plaster.

If short duration not a big deal. And as was stated, pebble is supposed to be 'immune' to problems, though I would not test that.

 

[JamesW]

I think that I would just do a simultaneous drain and refill.

Start a siphon if you can or some way to drain at about 5 to 10 gpm and then begin filling at the same rate.

Check the levels after a few hours to see where you are.

Watch the water level to make sure that it is staying the same.

Adjust the fill rate to match the drain rate.

 

[DanF]

Start a siphon if you can or some way to drain at about 5 to 10 gpm and then begin filling at the same rate.

Thanks James. I have an el cheap Harbor Freight submersible pump that I believe is 1/6HP (bought years ago and no markings on the pump). HF's website has current 1/6HP pumps that claim a maximum of 1600 GPH but I really doubt my pump pulls nearly that much.

 

[JamesW]

Just make sure that the pump does not leak oil.

You can put a valve on the pump output so that you can slow it down if it pumps faster than your garden hose at full speed.

Do you have an area lower than the pool that you can use to set up a siphon?

 

[JamesW]

1600 GPH

That's 26.7 gallons per minute.

That's at zero head loss.

As you can see here, the flow is dependent on the total lift, resistance or head loss.

600 GPH is 10 gpm, which happens at about 16 feet of lift.

 

[JamesW]

10 gpm through 100 feet of 3/4" garden hose creates 20 feet of head loss.

So, the flow would be about 9 gallons a minute through 100 feet of 3/4" garden hose if the elevation of the far end of the garden hose is the same as the pump end.

 

[DanF]

Thanks James! My lot is pretty flat (no opportunity for siphon) so I think I will try the "drain and simultaneous fill" approach. Issue with that method it's difficult to tell how much water one has replaced. I guess if I knew the GPH of my pump, and I filled such that the water level remained constant, I could guesstimate total gallons by the amount of time the process took.

Or like Marty said wait for monsoon rain, but that's pretty unpredictable here.

 

[JamesW]

You can get a 5 gallon bucket and see how long it takes the hose to fill it up to estimate the water flow.

Or, you can just keep the pool circulating and periodically check the salinity until it is where you want it to be.

 

[-MacGyver-]

After you turn on your hose go to your water meter and note the reading (include the tenths). Then keep monitoring your meter until you get to around what 12% would be. This is assuming you have municipal water and a water meter, if you are on well water and no "meter" you'd have to use the bucket method James suggested (do an additional for measure how long it takes to fill 5 gallon bucket from your hose and extrapolate the time for the 12% ) - heck you could use this method to figure out how long it should take to fill even with a municipal water meter.

When we filled our pool I monitored the water meter to get an idea of how much water was put into the pool. I also kept track of how many times we flushed (I had recorded how much water each used before hand, and subtracted that). If won't be exact, you'd be surprised how much you actually use water in the house.

 

[DanF]

Or, you can just keep the pool circulating and periodically check the salinity until it is where you want it to be.

This was pretty much the approach I ended up using. I pumped a inch or so out, fill it back up (either with the garden hose or the rain we've been getting) then rinsed and repeat. Pulled out the K-1766 this morning and I'm down to 3400. Thanks everyone.