please help me understand

[TrevNJPool]

My FC does not go below 6ppm. My CC are less than .5 or 0 all the time. But every once in awhile I get a very slight alga along the seam of the wall. I raise the FC up, vacuum the next day and pass the 3 criteria. I've moved the jets around for better circulation and swim every day to move the water around. Run my filter for 4 hrs at night and 3 hrs in the middle of the day. It is covered with a solar cover when not in use. I test regularly and everything is good.
Fc 10
Ph 7.5
Cc 0
TA 100
CYA 35
How does this algae grow. The water is crystal clear and has been all season. What am I missing?

 

[carveitup]

Don't know the answer but your thread pretty much beat me to it. Same issue here. Even your pool is almost the same as mine.

 

[Smykowski]

Is the algae dead or growing? That is, does it puff away very very easily, or does it take a bit of brushing to knock it loose?

 

[TrevNJPool]

It puffs away with my bare hand.

 

[Casey]

You need to be brushing your pools weekly. Lack of brushing is the biggest contributor to your algae. Imagine eating a Philly steak and cheese and NOT brushing your teeth. You'll have that sandwich far longer to munch on than you wish if you don't brush after eating yeah? Brush your pool and it will sparkle!

 

[carveitup]

More brushing does seem to be the conventional wisdom. But what is it supposed to do if there is no algae? Just force the water to circulate? I just don't quite understand what brushing a pristine pool is supposed to achieve.

 

[Smykowski]

If it's puffing away, it's probably dead algae. How clean is the top of your solar cover?

 

[Casey]

When you brush your teeth at night and go to bed, you obviously did not eat but you wake up and brush your teeth right? You have yuck mouth and want to get rid of it. Your pool, although it's chlorinated, has to have the biofilms that are growing all the time in it, brushed weekly to keep the *poofing* away. Every pool needs weekly brushing or it will do this. Even my pool does it. The consensus is to brush because it works even if the pool is pristine. There is no gimmick or science behind it. Water and sunlight cause algae. Chlorine kills algae and brushing is another tool to keep it at bay and let the chlorine kill it. A pristine pool has no algae.

Trouble free pool includes manually brushing the pool. No one called it lazy free pool. We still have to work pool side to keep the trouble free pool going by testing accurately, dosing accordingly and manually assisting the pool.

 

[TrevNJPool]

Okay I get that and it makes sense on the brushing thing for buildup of some kind. However, if the chlorine kills algae, shouldn't a properly and definitely over chlorinated pool not allow it to grow at all? We're not talking above the water line. Even if its dead it had to be alive to grow in the first place. If there is no brushing i can see a build up of something, but not algae since it should not grow at all. If I slept with a mouthful of listerine, i probably would not have to brush my teeth in the morning. That is why I'm baffled.

My solar cover seems pretty clean. I havent actually cleaned it. It is on a roller so the chlorine should keep it pretty clean, no?

 

[Smykowski]

I'm pretty sure algae spores are airborne. You're always going to get a little bit of something in the pool. Your correct FC/CYA levels will always keep it from taking over.

 

[TrevNJPool]

Its the first time i've seen it. Its kind of like a very slight light green ring at the base of the pool walls. Would it not show up in the test results though? How can u have 0 CCs and have a green ring around the pool?

 

[Smykowski]

CCs are combine chlorines (aka chloramines) which are the byproducts of chlorine oxidizing (usually nitrogen based) compounds. It's very common to see 0 CCs during a swamp clearing process.

 

[PAGirl]

If you don't expose the algae you can't see by brushing, (there's talk of film) might not register any CC's because it isn't reacting to the chlorine. I bought a good brush and brush every couple of days. It is insurance against any areas of poor circulation. Wondering if you checked for CC's a little while after brushing if they would show up then? Hope I made sense, not sure I explained what I mean clearly enough!

 

[Smykowski]

Let me rephrase....even if you have algae, you may very well never see CCs on a test.

 

[TrevNJPool]

Thats why this forum is great. I learn stuff all the time. I didnt think this was possible. Now i know. Thanks

 

[chem geek]

The circulation of water at a pool's surface goes to zero by definition (the pool surface itself is not moving). Unless you have returns pointed right at a wall, then the water flow in some areas will be limited more by diffusion than by circulation. If there are indentations in the surface, then there may be little exposure to the general chlorine levels in the pool in that area. If for whatever reason some algae spores get into that region, they could grow.

Brushing physically removes such spores and also stirs the water in the region to get chlorine deeper into crevices to oxidize anything in that area. If you have proper chlorine levels and brush, you can kill off everything in the crevices so that it is unlikely for regrowth to occur. If you don't brush, then shocking might diffuse enough chlorine to kill the surface algae but deeper in the crevice it is still alive and will come back. This is why we recommend regular brushing of pool surfaces.