Having trouble dialing in SWG

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Xexys

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May 11, 2014
180
Mesa, Arizona
So I've read that I really only need to run my pumps for 4 hours on this site for a residential pool. My configuration will turnover my water in less than 3 hours. What I'm having trouble with is maintaining the proper target value for my chlorine (6).

I run the pumps for 5 1/2 hours. I have my SWG set for 75%. Two days ago my chlorine level was 5 and yesterday it fell to 3. My SWG produces 567 gm (1.25 lbs) of chlorine per 24 Hour period, I'm assuming that is at 100% production.

I know this is all subjective, and all pools are different. Should I increase the % on the SWG? Should I increase the pump time?

FC-3
CC-0.5
TA-85-90
CH-320
CYA-75-80
Salt-3500

Main pump is 142 gpm. Cartridge filter can handle 150 gpm. Maybe some professional can chime in and give me a direction on what to do here? Or is this really just hit and miss?
 
4 hours is a subjective number at best. Run it enough to keep your FC high enough.........AND.....your water clear. Consider splitting up run time if you have a timer. I'd rather run the SWG at a lower percentage for a longer period of time to balance things out.
 
The size of your SWG cell will affect how long you need to run the SWG. We have a 13,700 gallon pool with a T-CELL-15 (rated for 40,000 gallons). I run the pump overnight for 4 hours with the SWG percentage at 25%. Most days, I run the spillover for 3-5 hours (depends how long we will be using the pool since my wife loves the sound of the spillover) and the SWG also runs at 25%. I keep our CYA around 50. Our pool is in direct sunlight all day...no shade. I try to keep our FC between 2-3 ppm. It fluctuates some depending on weather. If it gets a little higher, I just cut back on how long I run the spillover and let the sunlight burn off some chlorine.

I would be a bit concerned that your CC is not zero. Something in your pool is consuming chlorine.
 
VinceL said:
I would be a bit concerned that your CC is not zero. Something in your pool is consuming chlorine.
Click to expand...

This concerns me as well. I took the light out of the niche (needs replacing) and gobs of dirt was in there about 5 days ago. I'm feeling this caused my CC's to rise.

Also, a neighbor has a Mexican palm that is flowering and dumping flower buds in my pool. I've been raking out the little buggers 2-3 times a day for the last week.
 
Hello,
Adding some additional info. I've had an algae out break that wasn't visible, but consumed chlorine. It looks like your CYA/FC ratio may be a little low. If it dips too low, algae can get a foot hold and then, your SWCG is fighting a loosing battle.
I'd recommend you SLAM, Then increase your pump run time and your SWCG perentage, it cost more to run the pump, then cut that back first.

Hope that makes sense.
 
CC of 0.5 may not be a cause for alarm. If it goes to 1, then you should SLAM. You do need to maintain a minimum of 4 ppm FC for your CYA, so you need to get it up fairly quickly. What I would do first is to add some bleach to immediately raise the FC to around 6 ppm. I would also increase the SWG percentage and see if that keeps up with demand. If not, then I would increase pump time. But if CC rose to 1, I would SLAM regardless of what settings I did with my SWG.
 
My neighbor cut the flowering branches off his Mexican palm today after he came home from work. His wife and her friend got bombarded with the flower particles when we had a big wind blow through today. She told him to cut them down and he did.

I will increase the pump time as the SWG is already at 75%. I made a boo boo in my first post, my CYA is really 70 as I tested today. I threw some liquid chlorine today to get the FC up and will check tomorrow morning as I'm going to run the pump longer. FC is now 6 ppm.

Hopefully, this dialing in won't take too long. I just replaced the cell and the old one wasn't working at all for almost a year and I was using bleach/liquid chlorine to supplement the pool. That, plus I had many other issues with the system as I replaced the bottom and tops of both valves ( 3 +1, 6) and also fixed a pipe that had a small leak. I also rewired one of the pumps as I had a short right at the bend where the wires attach to the back of the pump. The pump didn't make it and had to replace it. That had been from January through April so the pool has suffered greatly so far this year. We had been fighting green pool all year which is what landed me here on this site. The information here is fantastic and so glad I can ask a question on an internet site and not get hassled by trolls. Really love the way this site is run.

My new light came today so I'll be tackling that probably Thursday as tomorrow I'm busy.
 
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Here's one of the shallow end:



Going to be working this weekend on that salt line you see just above the waterline. Total of 17 years and nobody has tried anything to remove it. Today I scrubbed a little MA on a test tile and it got it off with a little elbow grease. The pebbletec will be harder I'm sure.
 
With your old run time numbers I used PoolMath and calculated that you were only producing 1.2 ppm of FC a day. You will need to increase the run time and/or the % output until you start generating enough FC for the pool. The math used was:

5.5/24=.229 which is the SWG output time per day.

.229 X .75= .171 which is the output time X the SWG%.

.171 x 20 ounces= 3.435 ounces of chlorine made in a day. 20 ounces is potential of SWG output for a day at 100%. 20 ounces = 1.25lbs X 16 ounces.

Use PoolMath and insert your 22,275 gallons and 3.435 ounces of chlorine gas into the effects of adding chemicals and it calculates out to 1.2 ppm FC a day.
 
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Thank you so much ping. Where do you come up with the 20 ounces part though?

Running my numbers and using the 20 ounces would mean all sorts of scenarios. I could run my pump for 21.6 hours at 100% and achieve 6 ppm.

I could also look at it this way: I could run the pump for 12 hours @ 95% and produce my minimum of 3.2 ppm and put in half a gallon of 12.5% Liquid Chlorine and get 2.8 ppm which gives me my target of 6 ppm/day. If I knock the 12.5% Chlorine down to 40 oz I will achieve 5 ppm of chlorine/day, which would also be fine.

I guess I just need to know where you pulled 20 ounces from? But again thanks for putting the chemicals into math (which I can follow). If I put a value of 18 Chlorine Gas in the calculator, it will yield a FC value of 6.1 so I'm sitting here wondering if that's where you get the value of 20 from which would give me 6.7 FC...yes it's late and I hate when math defeats me.
 
You may also want to split your runtime. 50% in the AM and 50% in the afternoon / evening. Nice dose to start the day and another to kill anything that may have blown in during the afternoon for a nice sanitized pool overnight.
 
Here, we have power consumption prime time rules, on peak and off peak. From 1 pm to 8 pm in the summer, it costs extra to run anything. So, I have my pumps running until 12:45 pm. I believe I have it dialed in now, it'll just take a few days of monitoring to find out.
 
So, my wife is the patient one in the relationship and I do the knee jerk reaction stuff. She talked me into settling on some numbers and wait a week to change. I followed her advice and tested everything for a week and this is what happened.

According to the math, my SWG produces 20 grams of Chlorine per day as has been outlined in the previous posts. I set my SWG to 85% and set the run time to 9.5 hours from the late morning hours to 12:45 pm. Since my CYA is 70-75 I figured 6 ppm would be a good place to keep my FC and 7.5 is my desired PH.

It did not move off 6.0 ppm of FC for a solid week. The PH only required 80 oz of MA in the middle of my "test" week to get it from 7.8 down to 7.5 again. These numbers are fantastic! I'm overwhelmed with happiness that my wife got me to just settle down and wait it out. At 9.5 hrs and 85% SWG I produce 2.8 ppm FC/day. This is so cool that I can keep the FC from deviating off 6 ppm of FC.

Tonight I'm going to drop the SWG to a production of 80%, test every day and wait a week to see if I can keep the FC up. I wouldn't mind if the FC drops to 5 ppm and ideally that is really what I'd like it to do.

I have 15 and a half boxes of 20 mule team borax, a borates test kit and 4 gallons of 31% muriatic acid (plus more if needed) just waiting to go into the pool starting a week from tonight to get to a target of 46 ppm borates by Sunday after running the pumps for the weekend. I figure once I get the borates in my pool it will be almost care free and I'll have the disease known as "sparklypoolitis". :)

What WILL I do with my spare time?
 
Iciee said:
Please let me know how it goes. I almost have mine dialed in. My ph seems to rise and my ta has dropped to 90. I never had it that low when I used pucks


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Click to expand...

Will do, I actually did a full set of tests tonight as I dropped the SWG to 80%. One of the factors of adding boric acid is to get your TA to 70, which just so happens to be exactly what I tested. FC actually dropped a tad to 5 ppm which didn't surprise me at all being that I hadn't added any bleach but once since I put the new Salt cell in 5 weeks ago.

Here are my numbers:
FC-5
CC-0.0
TA-70
CH-275
PH-7.6
CYA-70
Salt-3,400

Seems the PH drifts up every 3-4 days, but that's expected with SWG's. Adding the borates hopefully will help with the rising PH. Going to wait a couple of days and hit the boost on the cell and see if that'll raise the FC. Trial and error...

Been awfully hot and windy the last few weeks here in the valley too which probably has contributed to the FC loss with junk being blown into the pool.
 
Don't forget.. When dialing in an SWG, you can supplement it with liquid chlorine to get you to the required level and let the SWG cover the daily loss. The SWG is designed to produce the amount of FC you LOSE each day, not get you to the required levels. So, if you think you need 4 hours to make 1.5 FC each day to cover solar loss but you lose 3fC, add the 1.5 FC via liquid and adjust either % or runtime! not both until you find the amount of runtime and% you need eachday.
 

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