Balancing a friend's pool - adjust which first, pH or TA?

[presse55]

This post relates to a friend's pool - not our hot tub!

Volume of pool: 60,000 liters; water is sparkling clear.

Numbers this morning using Taylor test kit:

• FC: 8.5 ppm
• pH: << 7 (below bottom end of color scale
  pH (according to pool store, notoriously unreliable) 6.8
• Base demand: 10 drops raises pH to 7.2
• TA: 30 ppm
• CYA: 150ppm

Pool owner:

• Uses tablets (unsure if dichlor or trichlor) blindly, without measuring levels;
• Also adds oxidizer pouch once a week;

Using tables in Taylor kit booklet, I would plan to adjust as follows:

• first: adjust pH to target 7.2 with 2.3 Kg of pH+ (soda ash, Na2CO3);
• side effect of first step: will also raise TA by about 30ppm;
• recheck pH and TA;
• second: adjust TA to target 100ppm;
  based on above reading - would expect approx 4Kg of TA+ (baking soda, NaHCO3)

I haven't adjusted a pool this size in a while. How does this look then?

Thanks in advance!

Ron
Montreal

 

[ajw22]

I would not push TA above 60 until you see what the PH does.

Get PH up and TA above 60 and monitor.

 

[JamesW]

I would raise the TA to 100 with bicarb. That will bring the ph into a safe zone right away and the ph will drift up from there.

You need to dilute to get the cyanuric acid down by at least half.

Don't drain more than is safe to do so.

You also need to educate them about the use of tabs.

 

[presse55]

Thanks guys, I'll adjust TA first and go from there!

Ron

 

[woodyp]

Uses tablets (unsure if dichlor or trichlor) blindly, without measuring levels;

Tablets are trichlor....granules are dichlor.