[Are The Lamotte Test Kits The Ones For The Uk]

Sorry to revive this topic but I see the Taylor ones aren't available still in the UK, so what is the best kit to use in the UK these days?

[Noob:How much pH Reducer to add?]

We've just bought an Artesian South Sea Spa (1200 litres). We had it 4 weeks and found lots of foam and bubbles and learnt that this was from people's deodorants and hair conditioner etc so I re-filled the hot tub 4 days ago. I refilled it and noone has been in it as I wanted to get the chemistry right. We live in a very hard water area. We were given some test sticks (https://www.aquachek.com/aquachek-chlorine-4-in-1/) from the company we bought it off (should I be using something better) and it's now reporting the chlorine level is fine but ph(7.8-8.4) and alkalinity is high(180-240ppm).  I knew this might be an issue so bought some ph Reducer which has Sodium bisulfate in it. I think I must have added at least 120-150grams of it so far over the last few days but the alkalinity and ph are still high. Am I safe to keep adding the Sodium bisulfate until the levels drop or have I already added way too much?  Thanks