What is this algae?

[sxch12]

I've been slamming for 3 weeks and water is clear but can't get rid of these brown spots and such? What is it? How do I get rid of it?

FC: 25
CC: 0
Ph: 7.2
CYA: under 20. I'll bring this up.

 

[jblizzle]

Um, if your CYA is under 20ppm, then why is your FC at 25ppm That is not good for your liner.

Have you tried the OCLT yet?

You sure you do not just get a lot of dust or pollen?

 

[sxch12]

I have the fc high thinking it's algae. Are you sure it's not? I thought if it's pollen it would be everywhere but it's not. It's like small clumps here and there and seems to come back in the same area. It's brown and sand like. I'll do the oclt and see what happens. So how can I tell?

 

[jblizzle]

Even if it is algae, you FC is WAY too high for your CYA level. Are you using PoolMath and the FC/CYA Chart to follow the ShockLevelAndMAINTAIN Process?

 

[sxch12]

I know it's way high but I was following pool math but cloudy water wasn't clearing until I did that and cc was a about .5 and 1 until I used high FC. Now cc is 0. I should mention the sandy is mostly in the sunny shallow area and very little on deep side. I was doing FC of 12 and didn't clear up so I doubled it.

 

[jblizzle]

Well, we would never recommend doubling the shock level ... you may as well start going to the pool store for advice if you want to just dump massive amounts of chemicals in your pool potentially causing damage. That is not the TFP way.

 

[sxch12]

I did the sock test. Put it on both return line and now there is nothing on the floor/walls but when I look in the sock I see nothing there too. I've left the sock for almost a week and the water is clear. So what is it? I will take the sock off this weekend and see if it comes back but if it does what can I assume it is?

 

[COBrien]

What do those brown spots feel like?

My guess was dirt/dust that gets blown into the pool, which settles in areas with little agitation/flow. I get lots of dust/dirt in the corners of my steps.

 

[kwall]

I have the same thing I think , I brush and vac. Its keeps coming back . trying to get my cya up to 30 I'm a little shy . It's driving me crazy the water is clearer then it's ever been

 

[pooldv]

It is a simple process to keep algae away and it is a simple process to get rid of algae.

To keep algae away keep the chlorine at target level for your CYA level at all times and never let it drop below minimum to keep your pool sanitized and algae free. Chlorine CYA Chart

If you do get some algae SLAM - Shock Level And Maintain your pool to get rid of the algae.

 

[domct203]

I know it's way high but I was following pool math but cloudy water wasn't clearing until I did that and cc was a about .5 and 1 until I used high FC. Now cc is 0. I should mention the sandy is mostly in the sunny shallow area and very little on deep side. I was doing FC of 12 and didn't clear up so I doubled it.

There is no shortcut to a proper SLAM. Doubling, or in this case 2.5X, the FC level is not going to make the SLAM take half the time.

A CC of 0.5ppm is acceptable per the SLAM instructions.

The fact that the algae cleared when you doubled the dose was probably coincidental and would have happened anyway.

Whatever you do, DO NOT go swimming in there until that FC drops below 10ppm.

Dom

 

[Beens]

Whatever it is, it is probably settling in the little indentations at the bottom of your pool. Unless your pool floor is completely flat anything that's not filtering out can settle down there. Any dirt or debris that I have in my pool always shows in the same places. Along the seams and in every little dent in the pool floor. (and I have a lot of them!)
I'm just pointing out that the fact that it shows up in the same areas could be something other than that it's algae growing there.

An OCLT should tell you if something is growing in the pool.

 

[MarianParoo]

Pass the SLAM, then try adding DE to your sand filter. It will help get the finer particulates out when you vacuum. That's all it looks like to me.

Pool School - Add DE to a Sand Filter

 

[sxch12]

So when I put the sock over the returns and run the pump it's crystal clear (I look in sock and no sand). When I leave the pump off for 24hrs. its' crystal clear. If I run the pump without the sock the brown stuff shows up. OCLT is 0 to .5. So, FC does not go down when I add chlorine in the evening and test in the morning. So, does that mean there is something wrong with my sand filter? It's much finer than sand that I see. Once I brush it then it disappears until I run the pump without the sock.