PH not going down in 10ft above ground pool.

[Tirral]

Hi we have recently got a 10ft above ground pool for the kids this summer.
The pool is a 10' Bestway Fast Set with filter. (3638 Litres)

The pool was set up last week with no chemicals and the water started to turn cloudy. I have ordered/received a kit containing PH+, PH-, Algicide, Chlorine and Test Strips. Also upgraded the filter to a second hand Fraher Ocean v4 sand filter with Shott pump capable of 7800 litres per hour.

I tested the water right away and as you can imagine the results where off the scales.

First results:
PH: 8.4+ (max on the strip)
TA: 240+ ppm (max on the strip)
FC: 0- ppm (min on the strip)

From what I understand from reading the instructions is that I need to get the ph and ta right before I can add chlorine?

So I added 56g of PH- and left it for the recommended 4 hours and tested again.

Second result:
PH: 8.4+ (max on the strip)
TA: 240+ ppm (max on the strip)
FC: 0- ppm (min on the strip)

Added 56g PH- and left over night,

Third result:
PH: 8.4+ (max on the strip)
TA: 180-240 ppm
FC: 0- ppm (min on the strip)

Added 56g PH- and left for 4 hours

Fourth result:
It had all gone back up again.

PH: 8.4+ (max on the strip)
TA: 240+ ppm (max on the strip)
FC: 0- ppm (min on the strip)

Added 72g PH- and left for 4 hours

Current result:
PH: 8.4+ (max on the strip)
TA: 240+ ppm (max on the strip)
FC: 0- ppm (min on the strip)

I'm at a complete loss to what I'm doing wrong and have searched to no avail.

I know test strips are not the best but that is all I have at the moment.

If you need any more information please as as I'm new to all this.

Tirral

 

[AftonJeeper]

The pH + and - stuff is over priced and does not work as well as muriatic acid and borax. Here is a list of the recommended chemicals for your pool.

If the test strip is somewhat accurate you would want to add some muriatic acid to bring the pH down. I would add some bleach or liquid chlorine to your shopping list as well. Here is a link for maintaining smaller or seasonal pools.

 

[Richard320]

With that high TA, it's going to take a lot of acid to move the pH down and keep it there. Just keep plugging away at it. You might want to target 7.2 when calculating the dose.

 

[Tirral]

The pH + and - stuff is over priced and does not work as well as muriatic acid and borax. Here is a list of the recommended chemicals for your pool.

The ph +/- came with a kit that also contained stabilised chlorine granules. I have read a lot over the last couple of days but don't seem to be able to get muriatic acid locally in the uk. The closest I could find would be brick cleaner but not sure if that would be a good idea?

 

[AftonJeeper]

Try searching for hydrochloric acid, I believe that is the proper name for muriatic acid. I saw Richard post in another thread about bleach being available at Tesco over there. Might be worth a shot.

 

[Tirral]

With that high TA, it's going to take a lot of acid to move the pH down and keep it there. Just keep plugging away at it. You might want to target 7.2 when calculating the dose.

I keep adding but nothing seems to be happening and it just seems like a waste of PH- which also contains sodium bisulphate to help with TA?

Would the sand filter be filtering or storing the chemicals?

Thanks

 

[Tirral]

Because my water gets turned over 2 times in an hour could I shorten the time that I need to wait to test again?

 

[pookiesunshine]

Some products labeled brick cleaner are in fact muriatic acid, that is, hydrochloric acid. If the composition is not listed on the product label, search for the products composition, MSDS sheets in US. Do NOT assume it is muriatic acid.

sodium bisulphate is a dry acid to reduce pH.

 

[Richard320]

I keep adding but nothing seems to be happening and it just seems like a waste of PH- which also contains sodium bisulphate to help with TA?

Would the sand filter be filtering or storing the chemicals?

Thanks

It's working.... slowly. Plugging your numbers into pool math, 56g of dry acid will only reduce TA by 6. You can probably get away with adding 200 or 250g at a time. If you predissolve it in a plastic bucket with some pool water in it before you add it, and then brush things around a little, you can recheck in half an hour.

Muriatic Acid might be called Spirits of Salt in the UK.

 

[Tirral]

Pool pump has been turned off for the last few hours and I have just tested again and I'm getting around PH 7.8 but TA is still 240 or over. How much PH- should I add for the 7.8 value?

Thanks

 

[Richard320]

Pool pump has been turned off for the last few hours and I have just tested again and I'm getting around PH 7.8 but TA is still 240 or over. How much PH- should I add for the 7.8 value?

Thanks

Poolmath tells me 204 g.

You should learn to use it. It's really easy. For you, top line of the cart, far right, change units to the metric system. Second line, enter water volume. Then plug in your numbers. If all you're messing with is pH, you just need to enter pH and TA in the now and a pH target then hit enter. It'll give you the dose in Muriatic Acid or Dry Acid.

 

[Tirral]

Thanks for the link.
I added 204g PH- granules this morning and left for 2 hours.

Result:
PH: 7.8
TA: between 180-240
FC: 0

Just added another 200g.

 

[Tirral]

Result:
PH: 7.8
TA: between 180-240
FC:0

I am confused as to why the ph is not reducing. Nearly used the 1kg bottle of ph-

 

[Richard320]

It is going down. And then it pops back up. More or less continuously. It's the inaccuracy of the test strip that's confusing you. If you could see TA in multiples of 10, you'd see it go down. When TA gets down closer to 100, the pH rise will slow down so that when it drops, it will stay down for a few days, or at least long enough for you to see the change on the strip.

According to Effects of Adding Chemicals in poolmath, 1 kg of dry acid will lower TA by 107.

 

[Tirral]

Am I better off adding muriatic acid to lower the ph and ta? I think I have found somewhere that sells the stuff but unsure if it is the correct thing.
Here is a screen shot.

 

[Richard320]

Close, but not quite. It's got some surfactants (detergents) mixed in SDS

What's wrong with this stuff? 6 x Kilrock Spirits Of Salt - 500ml (Total 3 liters): Amazon.co.uk: Kitchen Home
Straight acid. https://www.e-secure.biz/documents/897FG425JU/Spirits%20of%20Salt.pdf

 

[Tirral]

Thanks for the suggestions. I did wonder what serfactants could mean.
As you can tell I'm pretty new to this and really appreciate the help.
I was looking for something local to me and found some called metklean spirits of salts. Here is the data sheet. Does this brand look ok?

 

[Richard320]

That's the stuff. 32% HCl.

 

[Tirral]

Cool I'll go grab some. Will this work batter than ph- stuff?

 

[Richard320]

Cool I'll go grab some. Will this work batter than ph- stuff?

Yes. And also it won't be adding sulfur to the water. I don't know what conditions it would take for that bisulfate to make things smell, but why risk it?