Adding Buffer puts pH off the Charts!!!

[Nordo]

I have a 70,000L inground pebblecreted concrete pool.
I treat manually with liquid chlorine (and acid, stabiliser, buffer, etc).
Recently I noticed my total alkalinity was below 40ppm, so I added about 2-3kg of buffer.
My pH had been around 7.2, but it suddenly shot up to over 8.2 (off the scale on my 4in1 kit).
The total alkalinity only lifted to 60ppm.
I've added nearly 5litres of liquid acid and the pH is still over 7.8.

My pool supply company have recently changed many of their products from Purex to Phoenix Blue.
i.e. the Buffer is Phoenix Blue.
My gut feeling if that the Buffer is not Sodium Bicarbonate, but Sodium Carbonate - a pH increaser

Has anyone had a similar problem, or can clarify what is going on?
I've never had this problem before.

[Denniswiseman]

Don't buy pool store stuff, you are on the right track in how you are dosing your pool
Use these common products to balance your pool
Liquid chlorine (sodium hypochlorite or plain bleach)
Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
Soda ash will raise pH and TA
You really need to get yourself a decent FAS/DPD test kit (Taylor K2006c or TF Testkits TF100 in the states) to get accurate results

[Nordo]

Thanks Dennis for your quick and helpful response.
Regarding the "buffer" I have bought, is there an easy way I can test it to find out if it is Carb or Bicarb?

[Denniswiseman]

I would check the ingredients on the packet or the MSDS (material safety data sheet)
Every product should have those

[Nordo]

The bucket (10kg) definitely states "Sodium Bicarbonate".
I just think they accidently (or deliberately) added the wrong chemical during that run of buffer.

As far as testing to verify what is in the container, I've found that carb gives a much higher pH test reading than bicarb, but it is outside of the pH range of my test kit.

I get on well with the staff in the pool supply shop, so I might see if they have had any other complaints since swapping product supplier.
I have already approached them once, but they just fobbed me off.

[Denniswiseman]

While you are at the pool shop get them to test your water as well
You could also try a small sample of fresh water. Test before and then after dosing to check the results