FC number question SWGn

[roth79]

I had checked the numbers yesterday and the FC was 3 and I did see I thought a little algae on a step and it wiped off real easy by hand Friday night so I raised the Pentair swg to 100% all day yesterday and checked the numbers this morning, so the swg ran 8 hours at 100%.

this morning numbers
13000 gallons hydrazzo
84 degrees
PH 7.8
FC 3.5 only?
TA 80
CH 320
CYA 70
Borate about 35
salt 3200

It is spotless and the cell does show the proper lights on for generating chlorine, its only 3 months old. shouldn't it blast out more then 3.5 in 8 to 10 hours of running full blast? Shock or leave it alone, I do have some local PS liquid left over, dump 5 gallons in and lower the swg? I'm lost now.

Thanks and from one vet to the others, Happy Memorial day and if no one tells you THANK YOU.

R

 

[rdhetrick]

Probably time for the shock process. Most likely you have algae, more than you can see. To be sure, about 2 hours before dark, I'd elevate the FC with bleach to the shock level (28 for CYA=70) and get ready to do the OCLT. Turn off the SWG when you add the liquid. Tomorrow morning you will know for sure whether you need to continue the shock process.

SWG's are good for MAINTAINING FC, not so good for raising it significantly.

Thanks for your service!!!

 

[Vette]

First, Happy Memorial Day and thank you very much for serving

I see you have a TF-100 in you sig, can you do the FAS-DPD test and do the CC test to see if you have CC's? I agree that you should shut off the SWG and start the shock process, but if there are CC's, that would really confirm it.

 

[BoDarville]

roth79:

First off, thank you for your service to our country :handshake:

If what you saw on the step was truly algae, then you would need to go through the Shock Process. Although that may have been the only currently visible sign of algae, you could be on the verge of a full-blown algae bloom which could happen very quickly.

One test result that is missing from your post is Combined Chloramines (CC). This is one of the parameters that determines whether you need to shock.

Your SWG is not designed to crank out the amount of FC needed for proper shocking. You will need to add supplemental liquid bleach or liquid chlorine and test several times a day to keep FC within the target range for shocking (see Chlorine/CYA Chart link in my sig).

 

[roth79]

Thanks all the CC showed 0....

 

[roth79]

With the oversized Pentair IC 40 on a 13000 gallon pool I would think I should be able to crank up the fc running it at 8 hours a 100%, I know not shocking but ????

 

[frustratedpoolmom]

Nope, it just isn't designed to produce it fast enough and quite frankly if you've got something in there consuming the chlorine, it could be consuming it as fast as the SWG can produce it. Best way to tell is turn the SWG off and do an overnight test. A loss greater than 1ppm and you need to shock (with liquid chlorine) until the FC holds overnight (with the SWG off).

 

[roth79]

Heres my problem, I have to travel this week but my wife is here and I haven't showed her the testing yet, can I just add Liquid all week daily till I get back Saturday and just keep it high shock level numbers all week with the swg off? The calculator shows 28 so I can add 5 gallons tonight and have her adding a bunch daily till I get back?

Thanks

 

[JasonLion]

That isn't as good as actually shocking, since that might be too little or too much chlorine, but the odds are very good that it will at least keep things from getting worse and it might well clean up the pool.

 

[frustratedpoolmom]

Or add enough to get to shock level, confirm shock level, then run the swg daily to keep the level consistent till you get back. Hopefully there won't be much of a drop with just the swg maintaining the FC shock level.