is there a diluting juice that is ok in terms of no sugar or shite

[nailpolish]

sigh
dds love juice (the diluting kind)
mum has it at her house and since they hardly ever go there i dont mind her giving it to them
they dont pester me too much about having it in the house but i have been wondering if there IS an ok juice to give children
i have a thing about it rotting teeth, you see, plus i dont believe all the labelling "no added sugar" means "yes there is sugar in here but we havent added any more"

im not even sure about fruit juice diluted down

any info gratefully received

TIA

The citric acid site does say excessive consumption is bad for tooth enamel. I don't think the odd glass of Rocks is excessive....

hmmm now thats a good idea
i think dds would like pineapple juice. makes a change from orange or apple