High Salinity

[jaygrovr]

Hi guys, i have a 15k gallon plaster pool (pebble), and its fully automated with both acid and chlorine injection. This system has been working great other than a few times the injection nozzles getting clogged and the lines popping off the stenner pumps. Its an omnilogic with sense and dispense. I have been struggling to get my total alkalinity up, as it seems to drop to very low levels, like 30 ppm or even lower. The pool is 1.5 years old. I have recently noticed salty taste to the water so I bought a salinity tester and my pool is now 5000ppm salt. I think this was a gradual increase. The bather load can be high at times as I have 2 kids and frequent visit by friends.

I have ordered the test kit that you guys recommend and I will go through that process and post the results. Here are my questions:

1. Will this level of salt damage any of my pool equipment including heater, pumps, in floor cleaners, tile?
2. Should I convert to a SWG and use the salt? If so, do I need to reduce the salt down to proper levels or I will over current the SWG?
3. The only way to lower salt is to dump water and refill with clean water?

I am getting my test kit in a few days but would love to get the groups opinion on this. I have ordered a SWG for 25k gallon pool, a hayward brand.

thanks in advance.

J

 

[mknauss]

Check the CH level of the water. Unless you use softened water for make up water, it is likely time to drain the pool and replace with fresh.

Be sure the SWCG is rated for a minimum of twice your pool volume, preferably 3 times here in our climate.

The salinity will have to be lowered, especially with a Hayward system. Needs to be around 3000 ppm with a Hayward.

You are over adding acid due to the Sense and Dispense thing. What pH target have you been using? Should be 7.8 or 8.

 

[jaygrovr]

Mknauss, yea sorry, forgot to mention that, my target PH was 7.5, which I now understand was probably wrong, now running at 7.8, but its so annoying with hayward I get constant high PH alarms. So I didnt buy a big enough SWG then?

J

 

[mknauss]

If you got a T9 -- no, at a minimum get a T15. And even then, I hope you have a VS pump as you will need to run 24/7.

I would ditch the Sense and Dispense. It will not work with a SWCG anyway. The CYA needs to be run at 70-80 ppm in our climate.

 

[jaygrovr]

My hayward rep says that the saltwater and sense and dispense works fine, not sure why you think it wont function. I really like how that works and would rather keep how its running and not even install a SWCG. I already purchased the 25k salt cell, which I cant return, but I can keep it and try to get a larger cell. I do have a variable speed, but hoping to not run 24/7. I get roughly 70 GPM through my system and could get more if needed. CYA is the total aklalinity? If it was low or very low for a long time would that contribute to more salt in my water?

 

[mknauss]

CYA is stabilizer. You likely are running very low levels and using lots of liquid chlorine as the ORP that the Sense thing uses cannot handle levels above about 20 ppm. The liquid chlorine adds salt to the water. That is how your salinity got so high.

Not sure what rpm that is but I run the minimum needed to close the flow switch on my SWCG. That is about 1500 rpm for my system.

 

[jaygrovr]

Ahh.. Ok well I will have my test kit soon, how do I add CYA? what is the chemical needed to increase that? I could run the slower speed the rest of the time, but when the infloor cleaners run, I need much more flow and pressure so I run at 95% total speed.

 

[mknauss]

Time for you to fill out a signature. Helps us help you by knowing what equipment, etc you have.
The IFCS changes things on pump rpm. Crazy needing that pump rate. I spend less than $10 a month in electricity for my pool.

Cyanuric Acid aka stabilizer aka conditioner.

Again, if you raise it so the SWCG will function, your ORP will not work.

 

[jaygrovr]

Ok wow, so I am not going to run SWG then, I really like not having to constantly manage the levels, although that hasnt exactly worked out. I test the levels monthly, but plan on doing the more accurate testing with the kit I bought. If ORP doesnt work, wont the system still stabilize PH? I assume a SWCG is a very different way of managing a pool compared to just injecting bleach. It sounds like the SWGC just needs to run more and if you set it to run enough, it should keep the pool clean all the time?

Thanks again for the help.

 

[mknauss]

You should be able to disable the ORP and just use the pH side.
The SWCG will need to be adjusted some during spring and again in the fall.
Once you get a good test kit I would suggest testing more often at least to start as you learn your pool’s characteristics.

 

[jaygrovr]

Not sure how its possible to run a pump 24/7 and it only cost 10 dollars a month. The rates in vegas are 0.14 kw. That would mean that you have 71kw/h of available power a month, or 2.38kw/h a day. Running something 24hrs would mean that your pump would have to consume less than .10 kw an hour. Thats 100 watts.

 

[pjt]

Running something 24hrs would mean that your pump would have to consume less than .10 kw an hour. Thats 10 watts.

That's 100 watts.

My pump draws ~70 W and I run 24/7. Our electricity is a little cheaper, so my monthly cost of operation is ~$5.

 

[jaygrovr]

Thats amazing, I will try to run mine much slower speed and see if I can get it down to 100 watts.

Jason

 

[mknauss]

I only run our pump about 8 hours per day. ~200 watts at 1500 rpm.

 

[jaygrovr]

Ok thats great. So in the end your recommendation is to ditch the ORP sensor, install a larger SWG, and potentially add some CYA to get the level up so saltwater chlorine generation works. Additionally, I will need to drain 35% of my pool to get the salinity down to 3500, if I want to run saltwater system.

 

[mknauss]

Yes -- tentative until you get a proper test kit to see what all the water chemistry values are.

 

[jaygrovr]

Ok here are my results.. not great
FC 0.5
CC 0
PH 7.8
CL 2
CH 925
TA 40
CYA 0
Salt 4000ppm

I just added some chlorine balancer after this test to bring it up.. I will test again in 24 hours for CYA.

 

[pjt]

FC 0.5

You need chlorine immediately. Add LC now.

CYA 0

You need CYA now. Your FC has no protection from the blazing Las Vegas sun and is quickly depleted. Add enough to get a CYA of 30. Pass an OCLT before bumping up the CYA to ~60.

CH 925

You're at the upper limit of manageable CH. When the weather cools off, you'll want to drain and refill. Consider getting a water softener for your fill line.

Draining - Further Reading

www.troublefreepool.com

TA 40

Are you continuing to add drops until there's no further color change? (This is a back burner item; your immediate focus needs to be FC and CYA.)

 

[jaygrovr]

Ok sounds good, adding LC now, and already added CYA.. Ill let it run for at least 24 hours.

 

[jaygrovr]

I am guessing that my sense and dispense is just not working that great, which is a reason many people dont have it. I feel it works very accurately for PH, keeping things balanced, but using ORP for chlorine injection I guess has some issues. I am going to be converting to a salt water generator. I am hoping to get some stability here soon. I will test things again in 24 hours and post the results. So the CH is calcium hardness? Do they make smaller inline softeners? Something I can manually backwash or do I need a full blown softener? All my gear is outside and I cant easily plumb to the house softener.