After having had no issues with the pool for many years I have a sudden huge outbreak of black algae.  Free chlorine at spa+ levels, PH about 7.  After very heavy rain I always chuck in some chlorine granules (salt water pool) as extra insurance.  I then decided to add for the first time some algaecide. Blue stuff.  Must have copper in it as the concrete overflow went green. As did the grout.  Cleaned to waste a couple of times, and then a week or so later after more heavy rain the pool went black (including the plastic fittings) in a couple of days.  Free chlorine levels still very high, PH about 7.  Still not sure how it all went black.  Scrubbing at the top level black stuff with an aluminium brush is taking a lot of grout off (it was crocodile platinum).

 

Looking at my options I think a complete regrout (incl acid wash after removing the grout) would be the best way forward. Replace plastic fittings in the pool. Replace sand in filter.

 

Pool is 12 * 4 * 1.4m.  tiles are 10cm

 

What kind of price would I be looking at, or, indeed, can anyone here recommend anyone for a quote.

 

I am in Hua Hin.

 

Thanks.

You have done the right thing other than add the "Blue Stuff" Copper sulphate. You only need around "point" 3 PPM of this chemical to do its job. It only goes away with a backwash or heavy rain. By the sounds, you put way to much in. 

 

Weber pool grout is approx 3000 per tub which depending on your grout line thickness you get average 20 sq/m per tub. Then add preparation, acid wash, labour etc!

 

pH 7 is too low. 7.2 to 7.4 for a salt pool is ideal.

 

Black spot is normally a result of prolonged high pH and is an absolute pain to get rid of!

 

 

 

Yep. Instructions on the tub were in Thai and had no idea it could cause so much havoc.   What does confuse me is that the PH is always low (as I understand it the chlorinator works better if PH is slightly low)  and still was after I added the algaecide.  The only time the pool has had high PH was when constructed and the builder had a PH of 8-9+ and was dabbing algae with chlorine tablets.  As soon as I saw this I got rid of him and had to put in a lot of acid to get it back to neutral.

 

do you know anyone in HH who can do a good job ? I am quite happy to buy all the materials.

Unfortunately no to HH contactors. Normally we would offer to do it but we are on a project for at least another 4 weeks up Issan.