Switching to salt, do I need a new test kit and routine?

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Oh I didn't know the app had more features than the website calculator. I have it installed now, that's nifty.

So for testing I said current FC is 2 and my target is 4. Says to run it 18 hours at 18% for 33.5 hours. 33 hours is longer than there is in a day so what do you do once it hits that target? I can't run it more than 24 hours a day so with the way the pool uses up FC in the Florida heat how do I maintain the levels?
 
Mdragger88 said:
Test your current salt level 1st. Liquid chlorine & other forms of chlorine add salt to the water so u may be surprised at the level that’s already in the water. When u go to add the salt do as mentioned above & add a bag or so less than what PoolMath calls for as to not overshoot the target . Then let it circulate & test again the next day & add more if necessary. Do not turn on your swg during this process. When you’re adding large amounts of salt u always want the swg off. Small additions are ok as they dissolve & get mixed in quite quickly.
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Is this advice only if your main returns on the bottom of the pool are open? Salt is heavier than water and sinks to the bottom of the pool. If 100% of your return water is through the skimmers, why would you need to turn off the SWG while adding salt? At all points in time while physical salt is lying on the bottom of the pool, the concentration of salt in the water going to the pump and SWG will be lower than the concentration when all the salt is dissolved.
 
Skenn81 said:
I can't run it more than 24 hours a day so with the way the pool uses up FC in the Florida heat how do I maintain the levels?
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To start you should assume your daily FC loss is 3 ppm unless you have better data. Raise your FC to 10% of CYA using liquid chlorine. Set the SWCG to 100% for 18 hours per day. Test FC daily and adjust as necessary to maintain FC above target levels.
 
Anyone have any guesses at the minimum RPMs I can run the pump at to still have it be picked up by the SWG? I want to turn it down for these longer run times. It's screened in so I dont need to worry about much getting in it, and I will run it at 4 hours higher RPMs a day to keep the pressure based pool vac running. So 4 hours higher speed, and 14 hours low speed, just not sure how low I can go. I saw a few threads on this topic in these forums, I saw people say don't go below 1000 as that is ineffeicne, and many saying someplace between 1200 and 1400 rpms to keep the swg making the CL is about right.
 
You need to test it. Lower the RPM to 1200. See if that closes the flow switch. If so, lower to 1100, etc. Once you see what level satisfies the flow switch, add back 100-200 rpm for when the filter gets a bit dirty.
 
Are you in the 24 hour run time camp? When I was learning about all of this and how I had to extend my run time from my normal 4 hours a day to 18 or so some folks said set it to run 24 hours a day. However many you want for the high speed cleaning needs, then additional hours to get to the 12 or 14 or 18 for the SWG needs, then have it almost idle for the remaining time before it kicks back to high speed again in the morning.

I checked the programming on mine, I can only do schedules based on time, I do not have the ability to set it by days, so I can't, for example, only do high speeds on a Monday and Thursday for the cleaner. It's the same schedule every day.

Right now I have it set at 2500 for 4 hours because my pressure based cleaner is miserable and needs way too much water to be pushed around, and an additional 16 hours at 1500. I'll be turning the salt system back on in a couple of days once I get the salt up to the recommended 3600 and can mess around with the rpms more then.

The math says to add a little over 10 bags to get where I need to be. Following the advice I added 6, will test again tomorrow, and add more as needed. Hopefully by Wednesday or Thursday I will have that where it needs to be. Manual says 3600 for optimal, to start I need a minimum of 2000 for it to even work and 2600+ to have it operating at a normal capacity. Will test tomorrow and see where we're at.
 
I still fundamentally do not understand how this works. So we get this thing going in a few days, the salt is where its supposed to be, the FC hits its target after 18 hours at 100%, I get the CYA to 70 and the FC to 5 (using the levels here -- Chlorine / CYA Chart - Trouble Free Pool ) .. then what? What do I put on the app to figure out what a daily run should be?

I did read through this a couple of times: Salt Water Chlorine Generators - Trouble Free Pool

But still don't get it fully. I understand the time to percentage relationship - longer run times at lower % or shorter run times at higher %, not sure what is needed though. At 18 hours running at 100% will that make my CL really high once I hit the target? The app doesn't have a "maintain" mode on the salt section, if my target is 5 and my reading is 5 it just tells me congrats everything is how it should be but not how to keep it that way.
 
Skenn81 said:
.. then what?
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mknauss said:
To start you should assume your daily FC loss is 3 ppm unless you have better data. Raise your FC to 10% of CYA using liquid chlorine. Set the SWCG to 100% for 18 hours per day. Test FC daily and adjust as necessary to maintain FC above target levels.
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So what you mean is assume that if it's 5 today it will be 2 tomorrow so I need to generate 3 ppm a day? So on the app I enter 2 for the reading and 5 for the target..

So 18 hours a day at 50%, 12 hours a day at 75%, 9 hours a day at 100%

That is what it says I need to go from 2 to 5. Am I thinking about this right now?
 

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Each day your pool will lose so much FC. I am suggesting you assume it is 3 ppm per day.

For your 18000 gallon pool, your 30000 gallon rated SWCG must run at 100% generation for about 11 hours each day to get 3 ppm FC generated. Or a combination of % and time to equate that.

It is likely, this time of year, you may not be using 3 ppm FC each day. But test and adjust your SWCG and/or pump run time to get the FC to somewhat stabilize above your target level.
 
How does everyone deal with this who don't know to look on a website like this or play around with the apps and calculator?

Do people get these SWGs and then just hope for the best and get green pools just like when they toss in some pucks and hope for the best?
 
Skenn81 said:
Do people get these SWGs and then just hope for the best and get green pools just like when they toss in some pucks and hope for the best?
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You just pointed to why SWCG's can get a bad reputation. Pool owners are not educated on how they work nor the water chemistry needed to best maintain them. Pool 'professionals' are notorious for turning them off and putting pucks in the skimmer.
 
Skenn81 said:
How does everyone deal with this who don't know to look on a website like this or play around with the apps and calculator?

Do people get these SWGs and then just hope for the best and get green pools just like when they toss in some pucks and hope for the best?
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Yes - this happens all the time.
Also generally coupled w/ the purchase of an undersized swg (aka- 30k rated cell for 30k gal pool) based on the recommendations from a builder or pool store
When purchasing many people are unaware of how much chlorine their unit actually produces daily (in 24/hrs @100%) making it difficult to know whether it will actually meet their needs.
The manufacturers sometimes also make this info hard to find as well.
These factors can all be a recipe for disaster & some decide a swg is too much trouble because they were told it would solve all their problems & be set it & forget it. You won’t have these issues because u have done your research before purchasing & are gaining knowledge on how your system works & what it’s capable of.
 
Homebrewale said:
Is this advice only if your main returns on the bottom of the pool are open? Salt is heavier than water and sinks to the bottom of the pool. If 100% of your return water is through the skimmers, why would you need to turn off the SWG while adding salt? At all points in time while physical salt is lying on the bottom of the pool, the concentration of salt in the water going to the pump and SWG will be lower than the concentration when all the salt is dissolved.
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mknauss said:
If a high salinity surge of water goes through the SWCG when on it can create a surge of amperage that can damage the electronics.
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Why risk it?
 
Unrelated but will post here anyway as we are waiting for the salt content to be where it needs to be before continuing the process...

All throughout the resurfacing of the pool process up until yesterday of finally getting the SWG system installed all of the pool people did comment on how clean my pool looked. When the guy came to do the start up process he was so happy the pool was blue and clear as he said almost all of them that they go to are green by the time he shows up. The SWG guy yesterday made a few comments about how clear the water was and said how almost everyone they work with will call and complain to them, the resurfacing company, how their water will be green and they blame the installers.

Been doing this TFP thing since we moved here, this was a real world example of it working. I was pretty happy with getting their comments as it means I am doing something right.

Also, side note, I had no idea I could set this site to be my Amazon Smile donation until seeing it in the signature above last night. I've switched over so I'll do my small part to help the site keep on going.
 
Mdragger88 said:
Why risk it?
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Because as a chemical engineer, I understand density of solids and liquids, solids dissolving in water and concentrations. I don't know where this surge of high salinity water comes from. I'm more than willing to adjust my thinking if explained to me. It would come from salt on the bottom of the deep end if I left those bottom returns open. I don't.
 
Homebrewale said:
Because as a chemical engineer, I understand density of solids and liquids, solids dissolving in water and concentrations. I don't know where this surge of high salinity water comes from. I'm more than willing to adjust my thinking if explained to me. It would come from salt on the bottom of the deep end if I left those bottom returns open. I don't.
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You do u - but I definitely can’t suggest that others do the same & risk their expensive equipment when waiting a day harms no one & costs virtually nothing.
 
Mdragger88 said:
You do u - but I definitely can’t suggest that others do the same & risk their expensive equipment when waiting a day harms no one & costs virtually nothing.
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I will do me. I can understand the overall warning because some people will forget to close the bottom returns.
 
Okay so back to adding salt to the pool, besides dumping it in, brushing it around with a broom a bit, and waiting 24 hours, is there anything else I am supposed to do to make it get absorbed by the water or is it just a matter of waiting? I'll be doing my test again this afternoon to see where we are at. I was at 2,000 yesterday and added more salt around 3pm to get things closer to 3,600 as the manual says it wants.
 
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