Why is my SWG not generating chlorine?

Jump to latest Follow Reply
B

Bart

LifeTime Supporter
Jan 24, 2010
309
Northern Virginia
Background - this is my second full season of my pool. Last year I set the SWG to around 35% and it kept the pool clean and properly chlorinated all season. This year I've been bumping it up and up and up and I can't get my chlorine level above 1.0 and it's usually around 0.5. It's currently set at 95% and I'm fighting a small algae bloom. The only other point is that when the pool was opened, I had a massive scale problem. I did two no drain acid washes which cured my problem.

Anyhow, does anyone have any thoughts about why my SWG is not working? Could the scale problem have done damage to it? I did clean it with acid and saw a little "bubbling" but it looked pretty clean even before I cleaned it.
 
FC .5
CC 0
ph 7.5
T/A 100
CH 540
CYA 65

I had never cleaned the cell before and I was expecting to see scale on the fins, but I didn't see any. But maybe you don't actually "see" the scale? Also, after the cleaning, things didn't improve much if at all.
 
Your SWG is likely producing chlorine just as fast as the algae is consuming it. My understanding is that you have to manually add bleach to get the water clean, at which point the SWG will be able to maintain an FC level. Sounds like it's time to start shocking.


Sent from my Exhibit II using Tapatalk.
 
Bart said:
Interesting. So you're saying that if I get my FC level way up there (say 4-5), then the SWG will be able to stay ahead of the algae and keep chlorine above my current .5 level?
Click to expand...

Forgive me if you already know most of this - the way the question is phrased I'm not sure:

Raising the FC to 4-5 now will not stop the algae. However, once you are algae free (assuming this is the problem) then keeping it at 4-5 should keep algae from getting started.

If you have algae, the way to get rid of it is to follow the shock process detailed in Pool School. The process involves raising the FC up to shock level which is determined by your CYA levels. Look at this chart in Pool School to determine the level you need. Based on your reported CYA level of 65, that appears to be a FC level of 26.

You stop the process when three things are ALL true:

1) OCLT = 1.0 or less
2) CC level = 0.5 or less
3) Water is clear (meaning no signs of algae, no cloudiness, etc.)
 
Thanks! I didn't know most of that!

My main concern is still the operation of the SWG. Does the theory that the SWG was just barely keeping up with the algae production make sense? So if I shock the heck out of the pool and remove all the algae, will I be able to set the SWG back down 30% where I had it last year?

Is that a valid theory, or is there a bigger issue going on?
 
And while we're the subject of shocking.....

To get my FC up to 26, I'd have to add 11 gallons (or 14 96oz containers). What's the best way to do that? Can I just pour it into the skimmer basket, or is it better to go right into the pool?
 
Since you do have some chlorine in the pool, it makes perfect sense that you have a nascent algae problem and the SWG is just staying ahead preventing a full bloom. Do you have a test kit so you can run the OCLT? Your first step is to add enough bleach tonight and raise the FC to shock level of 26 for your CYA of 65. If you fail the test then keep your FC at 26 or slightly more until you can pass the OCLT. Follow UnderWaterVanya's post and you will be good to go.

Do not pour the chorine in the skimmer, just pour slowly over a return in the deep end if you have a deep end. You should also brush the pool after adding the chlorine to help distribute it and to get the algae off the walls.

Once the algae is killed off you will need to see what settings, pump run time and % output, to generate enough chlorine to meet at least the minimum FC level for your CYA. Follow the Pool School guide for FC/CYA, pool-school/chlorine_cya_chart_shock, to keep algae from forming. Your settings will vary during the year as the temperatures and sun angles are changing during the seasons.
 
If all the algae is removed, you may be able to lower back to 30% ... but you obviously dropped too low in FC for the algae to start.

Read the recommended pool chemicals article in Pool School which explains how to add chemicals. For bleach, slowly pour it in front of a return jet ... never put anything directly into the skimmer.

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 

Enjoying this content?

Support TFP with a donation.

Give Support
You can use 12.5% chlorine to save some lugging...add it slowly to the pool infront of a return...filter running 24/7 during the shock process. The theory is correct...the typical swg should only be relied upon to replenish FC from daily UV degradation and bather load and can not maintain FC when organics increase, such as during an algae bloom. SWG's maintain FC, while bleach should be relied upon to adjust FC levels. This will also help your SWG last longer, by not running it on 100%.
 
Bart said:
Thanks! I didn't know most of that!

My main concern is still the operation of the SWG. Does the theory that the SWG was just barely keeping up with the algae production make sense? So if I shock the **** out of the pool and remove all the algae, will I be able to set the SWG back down 30% where I had it last year?

Is that a valid theory, or is there a bigger issue going on?
Click to expand...
Maybe, although 30% operation got you here... You will need to fine tune it to meet the minimum FC from the chart.

Also to be clear; you can run the SWG while shocking but not when doing the OCLT test.


- Sent using Tapatalk
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply