What type of algae is this ?

[pakalrtb]

I've gladly maintained my pool with a BBB method, for over 4 months now.
All my values seems to be in check but I keep getting the grow of this "algae" . Can you please look at the pic and let me know what they are how to prevent them ?
They are quite hard to be scrubbed off. I need a metal brush for that. They do not feel slimey at touch and a simple scrub with your nail will generally be of no use.

FC : 4
CC : 0
PH 7.5
TA : 65
CYA : 45

P_

[attachment=0:2r734nmm]IMG_20110126_163349.jpg[/attachment:2r734nmm]
[attachment=1:2r734nmm]IMG_20110126_163306.jpg[/attachment:2r734nmm]

 

[Guest]

That looks like black algae to me. I know it isn't black now, but it will turn that way after it dies off. Keep scrubbing it with the stainless brush and it will go away. Also, make sure you keep your pH in check, as that seems to grow (at least here) when you do not stay on the pH.

 

[pakalrtb]

Yes they are dark greenish now, but sure they tend to go to the black side. You may be very well right about the PH, it tends to go high and I need to add muriatic acid every second day. But why does it keep going up? It is because I have an infinity edge and the water get aireated overflowing from the infinity edge ? I am really not using the pool that much this time of the year.
P_

 

[Bama Rambler]

How do you chlorinate your pool?

The edge will cause a pH rise. Might be worth your time to look into an acid dosing pump.

 

[pakalrtb]

I use liquid clorine at 12%, I generally dump the required amount every afternoon , a couple of hours before I turn the pump off.
Is there a specific pump/hardware for making the liquid clorination and/or the addition of the acid an autormatic process ?
P_

 

[Bama Rambler]

I use the Liquidator for chlorine addition and that's about as automatic as it gets.

As for adding acid, you'll want a good peristaltic pump. I like the Stenner pump and tank setups but there's a recent thread on automating pH. You can search using the Google search at the very bottom of the page to find it.