Total Dissolved Solids going up - Hot Springs salt system

SallyD

Member
Oct 8, 2020
8
Chaska, MN
I have a new Hot Spring Limelight with their Freshwater Salt System. Long story short, but my total Dissolved Solids go up mysteriously over 2 weeks and shuts the saltwater system off. Then I have to drain/refill start over. I've refilled 3 times since Labor Day. My dealer "expert" just says "there's a lot of 'junk' dissolved in the water making the meter read high". I'm trying to figure out where this junk is coming from and why a fresh refill starts fine, then boom, TDS starts go up. There's only 2 of us, we use it midweek and weekends. we rinse off in the shower before getting in. When the saltwater system IS working, I don't need many chemicals which is nice and I'm not dumping lots of stuff in it. But it's approaching a high reading again and I anticipate it will go over the limit within the week. And now it's cold here in Minnesota so draining/refilling isn't an option until spring.

Any ideas where the "junk" is coming from since my dealer has given up? I am asking for a refund of the saltwater system. Thank you!
 
How are you measuring TDS?

What chemicals are you adding to the water?

How much salt are you adding?

I suspect you are adding too much salt and are using test strips. Get the K-1766 Taylor Salt Test for accurate measurement of the salt level.

Are you following these instructions...

 
Thank you for responding.

I'm measuring TDS using the saltwater system display itself and salt test strips from the dealer. The salt test strips indicate between 750 and 1000 ppm. The saltwater system indicator is just a colored bar on the electronic display that doesn't show actual numbers. It went from low in the OK range to high in the OK range in roughly 5 days with just me soaking in it for about 45 minutes on day 3. I had to drain my first fill 4 days after because the meter on the saltwater system display went high and shut itself off. So on my second and third fill, I only added 1 cup of salt. User guide recommends 5 cups. 290 gal tub.

I have to hammer it with phMinus right after fill. Then the saltwater system comes online. When that is working (before TDS goes too high), I only need to add small amounts of the non-chlorine sanitizer and my 5-point test strips look good. I'm using the product they gave me which is potassium peroxymonosulfate.

Yes, I used those instructions (not that web site specifically, but the instructions they gave me match that web site).

However, I did not have my fill water tested first. The service guy said my soft water would be fine. I'm beginning to think that's not true.

I'm beginning to think my fill water has issues for two reasons:
- on fresh fill, only 1cup of salt is needed
- if I add a few gallons of fill to top off the tub, my saltwater system indicator bumps up.

I will get the Taylor salt test. Is there a test for TDS I could use on my fill water? Other suggestions?
 
Maybe @RDspaguy is familiar with your system.

TDS should not matter to your spa. It is the salt PPM level that matters.

Does your spa display differentiate between TDS and salt levels?

TDS in pool water includes Salt, Calcium Hardness, Free Chlorine, TA, and CYA and any other soluble substances that have been dissolved in the water.

 
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only need to add small amounts of the non-chlorine sanitizer and my 5-point test strips look good. I'm using the product they gave me which is potassium peroxymonosulfate.
I have heard that mps (monopersulfate, non-chlorine shock) reads as a salt to the cell, and should not be used with a salt system.


The service guy said my soft water would be fine. I'm beginning to think that's not true.
I have always heard that you do not want to use softened water in your pool or spa. I have no basis for this from personal experience, and have had customers who use soft water with no issues.
I would say fill with hard water and stop using mps.
Unfortunately, I am not at all familiar with the hot springs salt system, having never seen one, but I hear that they are problematic and many people have issues with them.
 
And now it's cold here in Minnesota so draining/refilling isn't an option until spring.
While a properly maintained tub shouldn't need draining and refilling every couple weeks, and I'm a couple hours south of you, I present a January drain/clean and refill. Snow on the ground as snow was falling. ;)
full


You can't leave it drained but you certainly can do a drain and immediate refill if not done over a super cold snap. (I'd also avoid doing it right before ice or a winter storm that may knock the power out while it's reheating still)
 
While a properly maintained tub shouldn't need draining and refilling every couple weeks, and I'm a couple hours south of you, I present a January drain/clean and refill. Snow on the ground as snow was falling. ;)
full


You can't leave it drained but you certainly can do a drain and immediate refill if not done over a super cold snap. (I'd also avoid doing it right before ice or a winter storm that may knock the power out while it's reheating still)
What pump are you using there? And where are you pumping out to? I'd have to pump the water up and into the house to a drain. Can the pump do that? (I'm a super newbie here...)
 
Just a common utility pump from Farm and Fleet. Can get them at any hardware store too. Most of the smaller ones have a garden hose connector. I just pumped it into my yard but you can certainly pump water up as well, so pumping into a drain shouldn't be an issue.
 

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I have a limelight flash 2nd year. I love it, it’s about 350 gallons. The sales people don’t know the systems themselves. The first year I had it I wanted to give up on the salt system too. My levels went high for no reason and I’d call them and they’d tell me to lower the output level to a 1 or2, which just made the entire water a mess. The salt reading is based on the salt you add to the water in the beginning. I had I believe 7 cups of salt or so. The output has to do with usage because it’s going to use the salt in the water to generate so much chlorine based on your need. So we were using the tub alit and it wasn’t keeping up with our chlorine needs because they told us to lower the output snc they just kept telling us to use chlorine each time we went it (defeating the purpose of the salt system) well when I drained and changed the water and added new salt everything was fine. There just must have been too much salt added the first time around and I was following incorrect info to fix.
Anyway, how is your calcium levels? Did you use the vanishing act bag at each startup? Levels for the salt system need to be about 25-100 I believe. Maybe that has something to do with it.
 
Another thought would be what kind of salt are you using. You can’t use just any, I stick to their brand because I’m scared not too but purity of the salt is important.
 
I have to hammer it with phMinus right after fill.
How much pH minus?

Use muriatic acid instead.

Note that conductivity salt meters cannot distinguish salt from TDS.

Conductivity meters only measure the conductivity of the water.

The TDS might be 100% salt (NaCl) to zero salt (NaCl) and the meter has no way to know.

Even a dual display meter like the MyronL PoolMeter that seems to measure salt and TDS really has no way to measure salt vs. TDS.

 
I have a caldera with the same salt system, it sucked at first until I flushed the tub with ahhsome so it wasn't fighting biofilm. I don't think that is necessarily your issue.

What your dealer is saying makes no sense to me. The on screen salt system measures the salt levels. Mine is fairly accurrate, however, you definitely need to get the salt right. I have a TDS meter that I use, the salt level and TDS are pretty close on the initial fill, but as you use the tub TDS will climb, while the salt will stay the same.

If by any chance you are using the Hot Springs/Watkins salt test strips, imho they are complete garbage and impossible to read. I'd highly recommend these strips, they are highly accurate and match the salt level as it should be based on pool math. The salt doesn't go anywhere, so really you don't need to check it that often, once you get really used to it, you hardly need it at all to be honest.


Do not waste your money buying the hot springs special salt, just go to any store and buy a bag of pool salt. You'll spend 20 bucks for 10 pounds of their salt, where you can get 40 or 50lbs of pool salt for maybe 5 bucks. I have filled up 2 or 3 times with normal pool salt, it is 100% fine.

Upon filling, add all the salt you need. For me, I add about 5.5lbs of salt for my 350 gallon Caldera Reunion spa. The pool math calculator will give you the amount, which will match close to the owners manual.

Finally, in my experience, they either need to check your salt system, or they need to give you a new cell to test. When I started with my tub, I burnt out two of the cells in 6 weeks apiece, because i had them set on the highest output constantly to try to keep up with the chlorine demand due to my dirty pipes( in my brand new tub ). After flushing with ahhsome( after I'd found this site ). I was able to turn the salt system down to level 4, and I'm right at 6 months on the current cell( I'm not replacing at 4 months as recommended, I'll run it until it quits producing chlorine ).

Anyway, I hope you can hang in there and sort it out. The system works really beautifully, but unfortunately my local dealer really didn't have the knowledge to guide me through it.
 
How much pH minus?

Use muriatic acid instead.

Note that conductivity salt meters cannot distinguish salt from TDS.

Conductivity meters only measure the conductivity of the water.

The TDS might be 100% salt (NaCl) to zero salt (NaCl) and the meter has no way to know.

Even a dual display meter like the MyronL PoolMeter that seems to measure salt and TDS really has no way to measure salt vs. TDS.


This is really interesting. Now that I think about it, you may be right, the "salt level" measurement on the system is probably just a TDS one. I'm going to pay closer attention to how it moves with my TDS increase over a few months.

If the original poster here has water with high TSD out of the tap, that could really throw off the system if it just is relying on TDS. I wonder if that has something to do with hot springs really urging soft water with these, so the base TDS of the water is really low. I know they say it is to keep calcium off the salt cell, but I've always found it curious they want calcium levels much lower than any other aftermarket salt cells. My city tap water is very low TSD, but someone on a well or with hard water might have to fight this.
 
@SallyD

Let's just summarize a few things here:

1. You're using softened water as your fill water. What is softened water? Well, hard water is high in calcium (Ca) and (Mg) and relatively low in (Na). Softened water is water that has had most of the Ca and Mg ions knocked out and replaced with Na ions.
2. Total Dissolved Solids is the sum total of the concentrations of all of the dissolved ions that are in the water. The main cations in water chemistry are Ca, Mg, Na and Potassium (K) but there can be others such as Manganese, Iron and others. The main anions in water chemistry are Bicarbonate (HCO3), Carbonate (CO3), Chloride (Cl), and Sulfate (SO4) but there can be lots of other minor players like Bromine (Br) and Borate (BO3). To calculate TDS, a lab would measure all of these concentrations and add them up or they could evaporate a certain amount of the water and weigh the chemical residue that gets left behind when the water has completely dried.
3. Your system's TDS sensor cannot measure TDS in either of these ways so it is almost assuredly measuring electrical conductivity of the water and then multiplying that number by a conversion factor to estimate TDS. This is a crude way of determining TDS. There is a correlation between EC and TDS in water but it's not a particularly strong one. The fact is though, the more solutes you dissolve in the water, the higher the EC will go and consequently your system's TDS meter will detect higher TDS
4. You do not know what the chemistry and what the TDS of the water you're starting with before you start adding salt and pool chemicals to it. Well, if your fill water is already high in TDS, you wouldn't have to add a lot more chemicals to it to get your TDS level to rise too high for your Tub's system to handle. Based on where you're living, I wouldn't be surprised to see the TDS of your fill water is high to begin with. That's just based on what I know of the geology and geological history of that region of the continent.
5. You say you initially have to pound your water with a lot of pH-Minus to get the pH under control. That says to me like your water might be high in bicarbonate which would mean the Total Alkalinity (TA) is high. High TA goes with high hardness so that makes sense. Dry acid is Sodium Bisuphate so that means you're adding more Na and more SO4 to the water, thereby increasing TDS even more. As another poster already suggested, stop doing this and start using Muriatic acid instead.
6. Then, after you add all those solutes to the water, you then add other things, particularly salt, NaCl. More Na and now Cl in the water. TDS increases even more. For a saltwater system you need to have a fairly high concentration of Cl so the zapper can turn it into FC. But how high was your Cl concentration to begin with? You need to know because that will tell you how much salt you actually need to add to get to the correct initial Cl concentration to start and run your saltwater system. The problem you seem to be having is that your TDS is already very high to begin with before you start adding salt. You then only need to add a little salt to get your TDS level up to where your TDS system thinks it should be but the TDS is made up of other ions and doesn't have enough Cl for your salt system to work properly. This is why your tests show your salt is low even though your TDS is high.

So I think the only way we can figure out the best way for you to manage your water chemistry we need to find out what the chemistry is of your fill water and it wouldn't hurt to also find out what the chemistry is of your water is before it gets modified by the softener. Once we know these things, we can figure out a way for you to get your tub water ready without sending the TDS level through the roof, or maybe we'll just find out that you can't use that salt system with your water because it's just too high in TDS to start with.

First of all, is it well water or city water you're dealing with? If it's well water I would fill up clean 500 ml plastic bottles with samples of your water before and after the softener and run them over to a lab to have a Routine Water analysis done on them. If it's city water, I would call the water works department and ask for a copy of the latest water chemical analysis. They do that testing all the time and will usually provide that information to anyone in the public who asks for it. My city publishes their latest test results on their website. That would give you the chemistry of the water you're putting into the softener. I would then get an analysis done of the water coming out of the softener so we can see what the difference is. We may find out that it would be better to use the unsoftened water as fill water or maybe fill with both types.

If you do get this testing done, ask the lab to provide the results in mg/L and not grains per gallon. Those are the dumbest units ever! It will be much easier to understand and work with the data if the results are provided in mg/L.

If you are using City water, it may be that their water is harder and has higher TA and TDS in the winter vs in the spring and summer. This is because the water gets diluted with low mineral content rainwater and snow runoff in the spring and summer. If you can get your system down to where you only have to do fresh fills once or twice a year, you could time them so as to avoid filling with higher TDS winter water.
 
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