Temperature and FC demand

[mk1]

All else being equal (sunlight, swimmer load, CYA), does a higher water temperature need more FC to control algae?

My water is about 90 right now......

 

[woodyp]

That's a great question and one I'm not 100% sure of the answer on. I know my pool sure seems to. It just makes sense to me that if heat degrades bleach when stored (warehouse,garage, etc.) that the same heat in the water would break it down faster too. Chime in somebody!

 

[duraleigh]

Unequivocally , "Yes!"

This is green pool season here at TFP. Many folks do not recognize the need to increase FC as the water temp warms. Add that plus increased bather load, length of daylight, etc.........all these things call for extra chlorine but many of us don't catch it early enough and wake up to a green pool one morning.

 

[woodyp]

But, but, but............as long as we stay above the minimums per the chlorine/cya chart we're still good to go........realizing that we may need to increase our target FC to keep that mimimum?

 

[duraleigh]

as long as we stay above the minimums per the chlorine/cya chart we're still good to go.

That's correct, but those minimums will sneak up on you more quickly now that the demand (consumption) has increased

 

[Smykowski]

All else being equal (sunlight, swimmer load, CYA), does a higher water temperature need more FC to control algae?

Let's clarify a little: The FC level required to control algae doesn't change. It is constant and only dependent on the CYA level of the pool. What does change is the speed at which FC breaks down in the pool, either due to heat/sunlight or because the warm water is a more inviting environment for algae to start and the FC has to kill it with greater frequency.

Bottom line, don't let FC get below min, but check it more often during the midsummer.

 

[Suziqzer]

Right... the minimum FC level does not change, however, the FC is consumed more quickly by the longer days, heat, bather load, etc... thus requiring more chlorine to be added to maintain that minimum level.

We can all say it a little differently.. can't we

 

[bullet20]

Ive been loosing 2-3ppm per day with the sun/heat SWG on 90% and heavy use.Also dumping a gal. of 8.25 bleech every couple days,I think i need a bleech drip system.LOL

 

[jblizzle]

Ive been loosing 2-3ppm per day with the sun/heat SWG on 90% and heavy use.Also dumping a gal. of 8.25 bleech every couple days,I think i need a bleech drip system.LOL

That sounds excessive. Either your SWG cell is not producing as much as it should or you have something "extra" in the water consuming your FC faster than the SWG can make it.

What is your CYA?

 

[bullet20]

Well iam offshore at work.I get in tomorrow,Ive been out for 7 days and it hard to get my wife to do test (lazy)LOL.
Cell been puting out prettty good (bubbles) goes up and down when % is change.
It's been clearing up sence open from a swamp but not crystel clear yet.Over night test have been less than .5 sometime .o
I think it's just been so much sun and heat down here,also kids been swimming everyday but not all day,mostly 2-3 hours late in day.
No body swimmed from last wed. till sun.,curious what my test would show now.

 

[bullet20]

Fc-1.5
cc-.5
Thats after 7-8 days with no care.SWG set on 90%
Dump 2 -128oz. 8.25 clorox when sun when down,waited a hour are so,now at 10.5.
I didn't get to check cya,but it was at 70-80 a week ago should be about the same.I just backwash before adding bleech.

 

[Cloudbusting]

at cya 70 your fc should be much higher at 6 ppm or so

you probably have something growing in there which keeps on consuming your chlorine

I'd shock the pool

 

[jblizzle]

at cya 70 your fc should be much higher at 6 ppm or so

you probably have something growing in there which keeps on consuming your chlorine

I'd shock the pool

Actually the recommended minium FC level as lower for SWG pools with 3-4ppm as the minimum.