Salt level keeps dropping

Chris_Ford

Chris_Ford

New member
My saltwater pool drops from 3200 ppm to 2800 ppm in a week. Is that normal evaporation, or could there be a leak?
 
That much of a drop in a week isn’t typical just from evaporation salt doesn’t evaporate like water does. If you're not backwashing a lot or draining, I'd start suspecting a small leak somewhere. I had the same issue and it turned out to be a slow leak near a return line. Definitely worth doing a bucket test to check if you're losing water faster than evaporation rates.
 
Happened to me too I kept topping off the pool and didn’t realize I was slowly diluting the salt. Turns out I had a tiny leak at the pump housing that wasn’t obvious at first. Also, check if autofill is running more than usual constant fresh water input can drop salt levels without you noticing.
 
One thing worth checking that sometimes gets overlooked: when and how you're adding water. If you’re topping off with a hose from a softened water source, it might be affecting salt readings over time.

I ran into something similar and realised I was using a water softener-connected spigot, ended up switching to an outdoor tap that pulls straight from the main line, and my salt levels stopped fluctuating so much. It might be worth a look if you haven’t already ruled that out.
 
Yeah, I ran into this exact thing not long ago, the salt level just kept dropping for no obvious reason. What threw me off was that there wasn’t any visible leak or anything soaking wet. Turns out one of the O-rings on my skimmer basket was cracked and dripping slowly, but it only showed up when the pump was running. Took me a while to even notice it.

Also, random but worth checking, if anyone’s been vacuuming to waste or doing filter flushes and forgetting to add salt back in after, that can throw it off without realising. Happened here once when my neighbour helped out while I was away.

Not saying it’s that exactly, but sometimes it’s the small, boring stuff causing the weird drops.
 
It’s also worth considering how often you’re topping off your pool with water. If you’re relying on a hose or garden tap to add water, you might be introducing a bit of fresh water without realizing it. Even a small leak around the return line or pump housing can lead to a gradual drop in salt levels, so it’s good practice to check all connections thoroughly. Also, if you're not running your pump continuously, you might not notice fluctuations until they accumulate over time. Sometimes it's the seemingly small things that create larger issues.
 
At this point I’m starting to think my pool is just salty about something and keeps ‘throwing shade’ by dropping salt on purpose haha..
 
Great points everyone! I’ve also read that sometimes pool covers can trap moisture, leading to a false reading of salt levels or causing more evaporation than expected. If you’re using a cover, it might be worth checking if it's trapping moisture under it. Anyone else had issues with covers affecting their pool chemistry?
 
Haha, yeah, that drop seems way too fast to be normal. Salt doesn’t just evaporate with water, so I’d bet there’s a tiny leak somewhere or some unnoticed dilution happening. I had something similar once; it turned out an O-ring on my skimmer was slowly leaking, barely noticeable until I looked.

Also, check if your auto-fill is on or if you’ve been adding water from a softener or hose; it can slowly dilute the salt. Backwashing or vacuuming to waste without topping up salt can also mess with readings. Basically, it’s usually some small, sneaky thing rather than a huge problem.
 
Chris_Ford said:
My saltwater pool drops from 3200 ppm to 2800 ppm in a week. Is that normal evaporation, or could there be a leak?
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My levels don’t drop that fast unless I’ve been topping off the pool a lot from evaporation. When you add fresh water it dilutes the salt so the ppm goes down. If you’re not adding much water and it still drops that much then I’d start checking for leaks. I had a small return line leak once and the salt test was the first clue something was off.
 
I’d also keep an eye on how you’re testing the salt. Sometimes test strips or even digital readers can drift a bit, especially if they’re getting old or not calibrated. I once thought my pool was losing a ton of salt, but it turned out the meter was off. Cross-checking with a different test kit gave me a much clearer picture. If the readings are consistent across multiple tests, then yeah, it’s probably dilution or a leak, but if they bounce around, the test itself might be the culprit.
 
I had something similar a while back and it turned out to be a mix of small things adding up. A slow drip at one of my pump fittings plus topping off with fresh water more often than I realized kept pulling the salt level down. At first I thought it was just “normal,” but salt doesn’t really vanish on its own—so if it’s dropping that much in a week, there’s usually dilution or a small leak behind it. Doing a bucket test helped me confirm water loss before chasing the leak. Might be worth trying that to narrow it down.
 
I ran into the same thing last season and at first I thought it was just part of owning a salt pool. Turned out it wasn’t evaporation at all, it was a very slow leak at one of the unions by my filter. Because I kept topping the pool off, the fresh water was diluting the salt and the numbers slid down week after week.

If you haven’t already, try a bucket test to see if you’re actually losing water. If the bucket stays the same but the pool drops, it’s likely a leak. If both drop together, it’s more of an evaporation issue and adding water is what’s cutting the salt.

Either way, salt doesn’t just “burn off,” so a 400 ppm swing in a week almost always points to dilution somewhere.
 
A rapid drop like that isn’t normal since salt doesn’t evaporate with water. Usually, it’s caused by adding fresh water, a minor leak, or using softened water. Try a bucket test to see if water loss is happening, and inspect your skimmer, return lines, and auto-fill system. Even a small drip can lower the salt level noticeably over a week.
 
A drop from 3200 to 2800 ppm in a week is definitely not normal, salt doesn’t evaporate with water. Most likely causes are dilution from topping up with fresh water, a slow leak somewhere, or occasionally using softened water.

A simple way to check is the bucket test: fill a bucket with pool water, mark the level, and leave it next to the pool. After a week, if the pool level drops more than the bucket, you’ve probably got a leak. Also, inspect skimmer gaskets, return lines, and pump fittings, sometimes a tiny drip can make a big difference. Once you catch the culprit, topping up with salt usually brings it back quickly.
 
I’d also take a look at when and how you’re testing. I once thought I was losing a ton of salt every week, but it turned out I was testing right after topping off with hose water and the reading came out lower until the pump fully circulated everything. After I started checking a day later, the numbers were a lot more stable. If you haven’t already, try spacing your test after the water has had time to mix, it can save a lot of confusion before chasing down leaks.
 
Yeah, that drop sounds a bit quicker than what you’d expect just from evaporation. In my case, I kept chasing numbers until I realised the real issue was a small drip at the base of my pump that only showed when the system was running. It wasn’t enough to notice a puddle, but over a week it added up and diluted the salt each time I topped off.

One thing that helped me figure it out was checking the water level every morning before the pump kicked on. If it’s consistently lower than expected, that’s a good hint something’s leaking. Also, give your fittings, unions, and filter area a quick look when the pump’s on, you’d be surprised how small a leak can mess with salt readings.
 
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