Need to shock? Algae?

[n8huntsman]

I've never had to shock my pool but have started getting what appears to be a little yellow/brown algae on the shaded sides of my pool. It's not bad and brushes off easily. It doesn't come back for a few days. The water is still crystal clear. I'll admit that I haven't been brushing the pool as much as I am supposed to but in the past, that never mattered.
Borates are 50.
My CYA is about 60. I am going to increase this to 70 today.
My CC's are zero.
My FC has been on the low side because my SWG is having trouble keeping up as the water temp increases so I keep increasing the filter time to compensate. The water temp is about 85 degrees now. I'm currently filtering on low speed from 9 to 5 and the FC has started to trend low again. Right now it's at 2.5. I'm going to add bleach to bring it up to 5. And Ill do a OCLT tonight. I don't want to increase the filter time again. 8 hours should be sufficient, correct? Does it sound like I need to shock the pool for the first time? Should I do it today or wait for the results of the OCLT?

Thanks

 

[Bama Rambler]

8 hours a day on low speed is really pushing it as far as adequate circulation is concerned.

Post a list of your equipment.

 

[duraleigh]

I would go ahead and shock. It's a tossup but it certainly sounds like mustard algae and your FC levels would indicate you are a candidate.

Don't be shy, shock it thoroughly with Liquid chlorine according to the FC/CYA charts (about 25+ppm) and then keep you FC up there until.....
1. Your water is crystal clear.
2. You lose less than 1.0 FC during the FC overnight loss test
3. Your CC's test is .5 or less

 

[n8huntsman]

Jandy PlusHP Pump 2 HP Dual Speed
Sta-Rite 450 Sq. ft. Cartridge Filter
cleva-chlor RP40HD http://www.cleva.com.au/products/chlori ... power.aspx
It's a dual cell unit and one of the cells wasa broken when I got it. But the two combined are rated for 40k gal. and I've only got 15k gal. so it kept up last summer.
How many hours on low should I be running it?
I just discovered I'm out of my DPD powder so I ordered some more. I'm going to put off shocking till that arrives. Maybe by then if I stay on top of the chlorine, it will go away.

 

[JamesW]

I'm going to put off shocking till that arrives.

Don't wait, get some chlorine in there as soon as possible. Filter 24/7 until the algae is completely gone.

 

[Butterfly]

I'm going to put off shocking till that arrives.

Don't wait, get some chlorine in there as soon as possible. Filter 24/7 until the algae is completely gone.

Yep +1

What is the pool surface? plaster, vinyl, FG?

It would help if you added your pool and equipment specs to your signature.
Go to User Control Panel (upper left, under TFP Logo), select Profile & then Edit Sig.

 

[n8huntsman]

Don't wait, get some chlorine in there as soon as possible. Filter 24/7 until the algae is completely gone.

That's the thing, the algae is gone. I brushed it on Saturday and it does not come back for about a week. The pool is plaster. My FC is now 3.5. Sun is down but it's still warm and fairly light out. Is that okay for the OCLT or do I need to check it again later tonight? I think I only have enough powder left for one more test.

How many hours on low should I be filtering under normal circumstances?