Forever low FC with SWG

hotingeorgia

Member
May 28, 2019
8
Atlanta, GA
Greetings,

I just had a 7,300 gallon fiber glass pool installed.

After reading TFP I was all excited to get started, trouble is I can't get my FC to stay at the recommended ranger. I have a Purechlor SWG and superflo vs. Based on what I've read here I've been running the superflo vs at 1100rpm for 5:30 at night with the purechlor set to the second to highest level. When the pool is busy I add another 5 hours of run time. The FC stays right around 1. I've also noticed my Purechlor comes in an out of "system error" and "check cell". I've checked the cell and the light will then go out only to return an hour later.
The "Add Salt" light hasn't come one. At this point I'm ready to give up on the SWG. Any help would be appreciated.

Info:
FC 1
TCL 1
ALK 120
PH 7.7
TH 400
CYA: 80
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Welcome! :wave: If the FC is truly that low, it won't take long for algae to bloom. Let's get some more data from you:
- How does the water look?
- How are you testing the water? Where did those results above come from?
- Do you have a good salt test kit? Do you know your actual salt level?
- How long has the pool been filled with water?

If you are using a TF-100 or Taylor K-2006C test kit and know the FC is truly that low, I would suppliment it with regular bleach until you can resolve the SWG issue. Let's see what info you provide and we'll go from there.
FC/CYA Chart
 
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hotingeorgia

Member
May 28, 2019
8
Atlanta, GA
Thank you for the quick reply!

1. Water is blue and you can see the bottom but is very cloudy
2. I just ordered a proper kit, I've been using test strips (embarrassing)
3. I still searching for a good salt kit, I don't think the Taylor K-2006C test kit includes a salt test. So I'm open to suggestions
4. Pool has been filled for a month, our pool installer was taking care of it the old fashioned way, when I switched over to the TFP that's when the FC started dropping
5. I've brought the FC up to 5 this morning with bleach based on the pool math calculator.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Gotcha! So it sounds as if the algae is trying to grow. Good you have a proper kit on its way. Which one did you order? Later make sure to include that in your signature with all of your pool and equipment info. As for the salt tests, checkout this page: Individual Tests (K-1000, borates, CYA, FAS-DPD, salt, pH meters).

Stick with the regular bleach and PoolMath tool. Once your kit arrives, post a full set of results and we'll walk you through the next steps.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
15,388
Bedford, TX
hig,

Sounds to me like you have two problems... The first problem is you have algae, which a SWCG will not overcome..

The second issue is that you are just not running your cell long enough..

Assuming you have the 15K cell, it puts out .75 lbs of Chlorine gas if run at 100% and for 24 hours.. This will increase the FC of your pool by 12 ppm or about .5 ppm per hour. A 5 hour run time gives you the bare minimum of 2.5 ppm per day and since you are only running about 75% then you are down to less than 2 ppm of FC per day...

Once you get rid of the algae, I suggest you set your output and run time so that you generate the amount of chlorine your pool needs... And... make sure you always keep your FC and CYA per this chart.. FC/CYA Chart

Salt cells only do what you tell them to do.. They have no brain, you have to be the cell's brain and use routine testing to decide to increase or decrease the amount of FC they produce.. Being a little high will not hurt anything, but being low will get you into the same position you are in now.. 😕

Thanks,

Jim R.
 

hotingeorgia

Member
May 28, 2019
8
Atlanta, GA
Jim,

Thanks for the reply. The info on the salt cell is very helpful.

I based my run time on what I saw others saying they ran there SWG for on the forums. I'd assumed that would work for me, you know what they say about assumptions...
 

hotingeorgia

Member
May 28, 2019
8
Atlanta, GA
I'm going to SLAM it today to end the algae.

after that it looks like my SWG makes 1.15lbs and hour., my pool is 7,300 gallons. So at 80% to keep an FC of 6 with a CYA of 80 i'm looking around 9.5 hours if my math is correct? Thanks again for all the help.
 

Fuldo

Silver Supporter
Nov 23, 2017
197
Port Orange, FL
Unless your electricity rates are much lower at night I don't understand why you wouldn't run your pump and generator during the day. During the day keeps the chlorine level more consistent and skimming during the day typically is more effective at collecting debris than at night when winds are typically calmer. Many folks here with VSPs run them 24/7 and simply set their SWG to a low setting. This will typically result in the cleanest pool and perhaps the optimum range and variation of FC.
 
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hotingeorgia

Member
May 28, 2019
8
Atlanta, GA
Fuldo,

Thanks for the feedback. I've heard mixed on this some users seem to push only running it enough to maintain FC as little as 4 hours depending on size: How Long to Run a Variable Speed Pump

I have a smart usage rate based on load and time of day, I run the pool when nothing else is running at night. I'm thinking about running it from 9pm-10am which would give it the longest run time when the rest of the house is off.
 

Fuldo

Silver Supporter
Nov 23, 2017
197
Port Orange, FL
Every pool, location and user is different including different conditions and priorities. I like the pool as clean as can be and that typically means starting the pump early morning and running it well into the afternoon at a minimum. This tends to trap the most debris before it sinks; keeping the surface cleaner and less debris to sink and accumulate on the bottom. VSPs use little power and I suspect if you run the numbers the difference in cost of running your pump during the day instead of at night for perhaps 8 hours won't amount to much, probably less than $10 per month mid season.
 
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an1vrsy

Bronze Supporter
Jul 10, 2018
138
Rancho Santa Margarita, CA
@hotingeorgia keep in mind that you stop generating chlorine at 10:00 a.m. at the end of your current runtime. The FC you have at 10:00 will not be the FC you’ll have at 5:00 p.m. So, if you test your water chemistry at 5:00 p.m. the sun’s UV rays will have eaten up a lot of chlorine.

So, you’ll have to ensure your FC is at a high enough ppm at 10:00 a.m. to get you through the day so you don’t fall below your target. For example, if you lose 3 ppm FC during daylight hours, you’ll need to be at 8 ppm FC at 10:00 a.m. with 70 CYA to be at FC 5 ppm at sundown. If you lose more than 3 ppm FC in hot Georgia during the day, your runtime will have to compensate.
 

PoolGate

Gold Supporter
TFP Guide
Jun 7, 2017
3,923
Damascus, MD
Confusing at best. With a SWG and VSP, run it 24x7. Maintain 10% chlorine level of your CYA and you will never have problems. There is no prize for running the lowest chlorine level possible. The only prize for low chlorine/pump run time is algae.
 
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tommyboyrn

Well-known member
May 8, 2018
71
Northeast Arkansas
I have similar SWG.....very easy to use and I have very good luck with it. Once we opened pool I set it from what we ran last year then titrated it over a couple days using the test kit to get chlorine levels where we needed it. We run our pump and swg 24/7 so it maintains the levels when we get them appropriate. Works for us......

Tom