Lewis, I would test the water twice:. 1st after adding your liquid fertilizer (I use FP and that itself lowers the pH some), then, if it is not to around 6.5, add vinegar till you can get it there. Once you do that...and if you have measured out how much vinegar you added to get it to 6.5, then you should not have to do it again. Vladimir found out his water's pH varied, so a periodic spot check may be wise. I checked mine recently but saw no difference.

Laura has it)

I believe that the pH of tap water can vary because the town may change the source of the water. My town gets its water from a number of wells and not all wells operate at the same time.

Yes, I am on well water and it is constantly in flux too.

Lewis, follow what Laura says. Check PH after adding fertilizer to the water.

Many fertilizers are acidifiers.

By the way, where did you get (if not confidential) a new zealand lemonade tree in UK?

It is near impossible for me to get one in Europe.

Thanks for all the responses, I've just been able to access my computer!

Laura,

I did not consider that fertilizer might acidify the water, so I'll definitely check the pH after adding it. My water comes from a reservoir and so I doubt that the pH will vary wildly, but I agree in that spot checks seem like a good idea anyway.

Axier,

Its from the Citrus Centre, a specialist nursery in West Sussex. They are truly amazing, they have all sorts of varieties and keep over 1500 trees (or something like that) including buddhas hand, lemonade, giant lime, etc etc

Lewis

By the way should I use ordinary white vinegar?

A bottle capfull of vinegar per gallon will not harm your plants at all even if the pH was lower..My water stands at 7.5 too and I use that much each time I water with great benefits...I would not worry about it) Save yourself the time for a tester)

Thank you Lewis for the info.

In Spain is easy to find near any commercial variety, but not so collection varieties like New Zealand lemonade, you are fortunate!