Black Spot Algae not going away :(

[CrankHead]

Hi all,

have got quite a few spots of black algae in the pool, have previously put in 20lt of chlorine but to no effect. I had also put in an a liquid algae killer that the local pool shop gave me. But no joy.


here is the pic of the problem area in pool http://imageshack.us/photo/my-images/81 ... renjy.jpg/

Here is the pool chemistry.

http://img844.imageshack.us/img844/7880/capture2up.jpg

the frequent rain here in Brisbane may have contributed as well.
thanx a lot for your help.

 

[257WbyMag]

Welcome to TFP!

Looks like you need to shock your pool. Black algae is especially tough to get rid of. It requires high levels of chlorine over a longer period of time than the regular green stuff. Also, you really need to spend lots of time brushing the area(s) well.

Please read pool-school/defeating_algae and pool-school/shocking_your_pool.

You also really need a good test kit. There are a couple of choices at www.tftestkits.net.

 

[CrankHead]

thanx for the reply. to shock the pool I read the pool-school/shocking_your_pool article. I have a question though.. according to this chart pool-school/chlorine_cya_chart_shock my CYA is 20, so how much Liquid chlorine do I need to add to get the Shock FC to 10 ?

Also do I add Algae killer as well at the same time and give it a good brush ?

 

[George N]

you need to enter the approximate gallons of your pool into :
http://www.poolcalculator.com/
Then you will see how much bleach you need.
You don't need an Algae killer, bleach will do it.
And welcome to the forum.

 

[CrankHead]

thanx 257WbyMag and George .

according to the pool calculator, for my 40000 lt pool I need 5.2 liters or 2.6 (2 liter) jugs of 6% bleach.
so do I only add the bleach or do I add the liquid chlorine as well ?

sorry for asking silly questions.. really new to this.

and thanx a lot for helping me out and thanx for welcoming me here.

 

[HoleInOne]

Liquid chlorine = Bleach

 

[George N]

Thanks HoleInOne, and I apologize CrankHead I'm just used to saying bleach.

 

[CrankHead]

hi guys, the pool shop gave me BioGuard Power Chlor and told me to put the lot in the skimmer while the pump is running. Later in the evening I will take a water sample to them for a check.

 

[maxepr1]

Do you have your own test kit? Pool stores are notorious for errors in pool tests. When shocking Bleach will be the cheapest way to go. And you will need your own test kit as you will be testing multiple times per day.

 

[CrankHead]

havent got a test kit at home, which one is recommended ?

 

[George N]

I and many others on this forum recommend this one: http://tftestkits.net/splash-page.html

There are others that you can read about in Pool School but I would go with this one.

I hope you have been reading Pool School in your spare time?

 

[CrankHead]

I and many others on this forum recommend this one: http://tftestkits.net/splash-page.html

There are others that you can read about in Pool School but I would go with this one.

I hope you have been reading Pool School in your spare time?

this mob http://tftestkits.net/splash-page.html dosent ship to Australia....

I clicked on the pool school link on ur signature but that didnt work....


yeah been reading it , but its huge and some of the terminology takes me time to absorb.

 

[Keven]

Take a steel brush and brush the spots to kill the head.. Take trichlor and sprinkle it over the black spots, the trichlor should start removing the spots. Do a test spot with the first to make sure it doesn't damage the plaster color..

 

[George N]

Sorry about the link CrankHead, it's working now (someone, not saying me messed it up.) And the one in the upper right of page always works
Might be helpful to put your pool information in your signature.