Anyone know of a pool company in Phuket where I can test pool water for phosphate? My regular shop does tests, but not for phosphate.   Thx

Unless it is a commercial pool why bother? The test kits are expensive, hence the shops won't do it. There should be a lab at the water authority! When I was at Ramayana it was done monthly by the water authority. If you suspect you have high phosphate, just dump some water. That is how you fix it anyway!!

Thanks for that, it got me doing more research. I'm starting my first battle with black algae, wish me luck!

 

Chemical supply houses usually have test kits for a range of compounds. From memory, testing for phosphate involves reaction with molybdic acid to produce a yellow complex.

I agree water authorities would have to be testing for phosphate, as it is a nutrient in waste discharges.

Is it black algae, or mould? A dose of copper sulphate may be your friend.

12 hours ago, mikejphuket said:

Thanks for that, it got me doing more research. I'm starting my first battle with black algae, wish me luck!

 

Lower the ph into the low 6. (Acid) Get some black algaecide & dose according to instructions. When dead, scrub with a wire brush and at the same time vacuum with the hose & not the head. Meaning that in one hand have the wire brush & the other the vacuum hose. After this is done it would be a good idea to use a chlorine pill and rub the areas very hard with the pill. Do a backwash asap after this. 

 

Black algae can come from anywhere so I wouldn't bother with the phosphate test. It can be introduced by bathers & it can be airborne. If the water is out of balance then it is easier for black algae to take hold. Typically constant high pH is the main reason it takes hold. 

13 hours ago, Lacessit said:

Chemical supply houses usually have test kits for a range of compounds. From memory, testing for phosphate involves reaction with molybdic acid to produce a yellow complex.

I agree water authorities would have to be testing for phosphate, as it is a nutrient in waste discharges.

Is it black algae, or mould? A dose of copper sulphate may be your friend.

Do you have experience with copper sulphate and black algae?

1 hour ago, Bagwain said:

Lower the ph into the low 6. (Acid) Get some black algaecide & dose according to instructions. When dead, scrub with a wire brush and at the same time vacuum with the hose & not the head. Meaning that in one hand have the wire brush & the other the vacuum hose. After this is done it would be a good idea to use a chlorine pill and rub the areas very hard with the pill. Do a backwash asap after this. 

 

Black algae can come from anywhere so I wouldn't bother with the phosphate test. It can be introduced by bathers & it can be airborne. If the water is out of balance then it is easier for black algae to take hold. Typically constant high pH is the main reason it takes hold. 

How necessary to backwash to waste? I have a large pool and will meaning losing a large volume of water.

Just a normal backwash of about 3 minutes. Just have to get it out of filter asap. Best if you have "Eco Clear" Recycled plate glass media. Nothing sticks to it and it is far superior filter media that last 15 yrs. Not the recycled bottle glass.

 

Copper sulphate is not appropriate for black spot. Use black spot algaecide. 

Thank You