Adjusting SWG Output %

[Cayman]

My FC has just recently dropped below 10 so I have been monitoring it daily so I know when to turn my SWG back on. (For those of you who do not know, I shut it off due to an algae outbreak where shocking my pool took the FC up to 40. I have been letting it decline with the SWG off since)

So I checked the FC last night and it was at 7.5 so I decided to go ahead and turn on the SWG and it was set to 40%. My pump is currently running 10 hours a day (2 - 5 hour cycles with about 3 hours off time in between). Tonight I checked it again and the FC has gone up to 8.5.

My question is this... If my FC was 6 with 10 hour run time and the SWG set to 40% under normal winter conditions with no problems and water balanced correctly... then if I had to shock it thus shutting off the SWG and turned the unit back on when the FC dropped back down to 10.... which of the following would likely be true and best describe what would happen?

1) The FC continues to slowly fall until it hit 6 and then stay there

2) The FC will never get back down to 6 from 10 using the same 10 hour pump time and 40% SWG setting

3) The FC will climb from 10 and continue to move higher

4) The SWG % will have to be dropped until the FC is at the targeted 6, and then set the SWG back to 40%

5) None of the above (Please explain)


I ask this because this is my first time adjusting the SWG % and I just want to know how to do it properly and what to watch for... especially since I just turned it back on last night and my FC has already gone up 1.

Thanks everyone!!!

 

[JasonLion]

The basic rules for adjusting the SWG percentage are:

Always test the FC level at about the same time of day, preferably in the early evening.

Give the FC level at least 24 hours and preferably a couple of days to settle between adjustments (unless your current setting is way off).

When FC is too high, lower the percentage. When FC is too low, raise the percentage.


It is difficult to guess how much you will need to adjust the SWG percentage. Where you need to set it varies noticeably as the water temperature changes. It sounds like you need to lower the percentage, FC is above target and rising, but it will take some experimentation to figure out how much to lower it.

 

[Cayman]

Jason... Thanks for the information but I do not think that 100% answered my question. I totally understand checking and testing in the evening as well as up for more FC and down for less. I also understand to wait 24-48 for the ajustment to take place.

Based on your comments, if consider everyting being the same (testing of all chemicals, water temp, etc.) and 40% was the correct output percentage for a FC of 6, what would happen if my FC was at 10 and I turned on my SWG to the standard 40%? Would the FC finally drop to 6 and then stay there?

 

[Strannik]

not necessarily

considering you just had algae outbreak, you don't know how long your SWG was trying to battle it
maybe those 40% were normal with some algae hiding, but now you'd be able to run it at say 30%
that's why you need to turn it on and test

otherwise, all things being equal before treatment and after, i'd say it's a fair assumption to make that if you turn it on now it will gradually drop to 6

 

[Cayman]

otherwise, all things being equal before treatment and after, i'd say it's a fair assumption to make that if you turn it on now it will gradually drop to 6

That is what I was trying to find out so I know what my plan of attack is and how things are going to react. Yes, I did have an algae outbreak but in my example, I removed all issues and made everything hypothetically perfect. :-D