Cloudiness at lower FC, clorine consumption

Jump to latest Follow Reply
P

pauster

0
Feb 4, 2008
49
Princeton, NJ
Hi Everyone,

recently our pool water has given us trouble - was not an issue for the last 5 years that we have had the pool.

Issue: Even at 100% output, the SWG is not keeping up with the chlorine consumption. (We replaced the cell last year.)

Water became cloudy, FC to 1.0, so I shocked with bleach. Got it up to 12PPM FC - 0 CC and held it for 5 days- water cleared up again.

FC dropped from 10.0 to 1 in a week. Water became cloudy again. Yesterday I shocked it again to 8-10PPM, and it is clearing up again.

Water temp - around 75-78 deg these days.

CYA: 70PPM-ish
TA 70 PMM
CH - 210 ppm
PH I manage it to stay around 7.4 - adjusted with Muriatic Acid as needed
Salt: 2700ppm

At the return nearest the pool, we see offgassing of CO2 proportionally to the level of the SWG we set. It bubbles away happily. So I would deduce the SWG works well but I can't measure it directly.

Built 5 years ago
25K GAL inground, Quartz surface
Jandy Aquapure - replaced cell last year
Solar heat
Brand new 425SF cartriges in filter .
Location - NJ

I see no evidence of algae - so what could be the source of chlorine consumption? We had lots of rain (>6 inches) in the last weeks But I don'1 think that's an issue.

The use is light - mostly my kids and I and we are trained in pool hygiene :eek:)

So any ideas what might be wrong?

We're tempted to drain and refill (which we haven;t ever done in five years) but I'd like to avoid the trouble.

Thanks!

Patrick
 
Thanks - so is there invisible algae somewhere? The water looks fine and there is no hint of green - the water just gets cloudy/milky at low FC ...

So should I just shock to 20-30 PPM FC to kill the buggers? The chlorine vendors will love me!
 
You shock when any of the following occur:

1) Water is not clear (you're wasn't, it's cloudy)
2) CC > .5
3) OCLT > 1
<unwritten> you let FC get below minimum

Your water is not clear and you let FC get well below minimum for your CYA. Time to follow the shock process. Don't ever let FC get below minimum (which is 3 for you at CYA 70, if you're closer to 80 then it's 4) or you'll likely have to go through the shock process again. It doesn't take long if your FC is low for algae to grow even though you can't see it. It can take hold in a day at low FC. That your SWG can't keep up with what's consuming FC at your normal settings is a dead give away of something growing in the water.

My guess is it will only take a few days to knock out what you've got by following the shock process. When you upped your FC to elevated levels (but not SHOCK levels) you knocked the algae down, but you didn't knock it out completely. Shocking properly totally eliminates it.

-edit-
Re-read your post again. Don't shock to "20-30", maintain 28 and don't let it drop below 28. Sometimes this can mean adding bleach every other hour or so to maintain.
 
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