What the ...?

[Vickery]

Pool water is sparkling clean.

This am test results:

FC - 6
CC- 0
PH - 7.8 (I'll do my usual two week dose when the timer kicks the pump on this morning)
CYA 80
TA 90
Borates 50

I cycle the pump for six hours at 10 am. So why are there small light green patches of what look like algae that are in the footprints in the floor and cove area at the end furthest from the return? And yes, I tested the water there and the CL is still 6.

Suggestions?

 

[duraleigh]

If it has collected in the "divots" of your pool floor or areas with low circulation, it is likely dead algae but that means you had (have) live algae that you cannot see.

The simple answer is that algae does not live in an environment that has adequate chlorine. If you see dead algae, you must add (and keep) a higher chlorine residual than you have been

 

[Vickery]

That was my impression as well...but maintaining an FC of 6 until the start of a swg cycle ought to have killed any algae. Or at least that's what I gather from the chart. I'm going to crank up the swg a bit more today, but it has been fine until Monday. FC dropped down to 4 due to a GFCI trip, but that should have still been sufficient to kill the stuff.

 

[jblizzle]

Dropping to a FC of 4 is too low and it would allow algae to get ahead.

 

[duraleigh]

One of the single most import "buy-ins" (things you have to believe) in what we teach is chlorine's ability to kill algae. If you have algae in the pool there's not enough chlorine. Maybe it's because we didn't brush often enough....maybe it's because algae can find an area of pool circulation and hide out....maybe it's because the bleach is too weak.....maybe it one of many more reasons....who knows.

That said, how often is the answer "Oh, you need less chlorine!"? Of course, never.....the answer is always you need more chlorine....perhaps better distributed, perhaps this or that but always. "you need more chlorine".

We should never be surprised when algae grows in our pools, we always know the answer. Most of the time it is simply the addition of more chlorine and nothing else.

 

[domct203]

If you have visible algae, maintenance FC levels may not be enough. Algae reproduces very quickly.

You could do an OCLT to be certain, but if this were my pool I would SLAM.

 

[Vickery]

In reference to the CYA/Chlorine chart, 4 is minimum, 6 is target with CYA 80 (actually the dot has a slight almost shadow at 80, gone at 70.) According to the Recommended Levels, 3-5 FC. Water is crystal clear, 0 CC. I'll do an OCLT tonight to determine whether or not I SLAM. My first thought was circulation issues, which is why I took another test sample from the area of the suspected algae, still 6. I have no problem with elevating the CL levels, I just dialed up the swg. The mystery to me is why do I have any algae at all while maintaining what should be sufficient levels? Another great mystery of Pool Life?

 

[jblizzle]

Like Dave said not enough chlorine. Perhaps letting it get down to four at the bare minimum allowed a localized low FC spot. And as Dave also said the answer is always add more chlorine.

 

[pooldv]

Agreed, my pool cannot be anywhere near minimum for any period of time without a little algae dropping by. We have too many trees and varmints contributing to our pool. I treat target as minimum and generally keep my FC a couple above target for a little extra help. More chlorine is always better than less. It is safe to swim up to shock level and it is not safe to swim below minimum.

 

[domct203]

Agreed, my pool cannot be anywhere near minimum for any period of time without a little algae dropping by. We have too many trees and varmints contributing to our pool. I treat target as minimum and generally keep my FC a couple above target for a little extra help. More chlorine is always better than less. It is safe to swim up to shock level and it is not safe to swim below minimum.

This is exactly how I manage my FC, I use the target as my minimum due to two large trees constantly dropping organic matter into the pool.

 

[Griswald]

Same here in the hot and humid south. I keep my FC at or above the recommended number because a short lapse is a quick trip to algaeland. Heck, the stuff grows on our vinyl siding and shingles!

 

[Vickery]

Outside of the pool "Wet and Forget" is ABSOLUTELY required! It kills algae, mildew, moss and all manner of humidity loving green nastiness. Costco is best source, ACE Hardware as well. Simply spray until the green is wet....and f'gettaboutit!

 

[Vickery]

Results of the OCLT:
Start - FC 7.5
Finish -FC 7.5
CC - .5<
New FC target - 7.5

The TFP methods are just tooooo easy....