advice please

Due to uncalibrated ph meter my plants have been watered with around 3.8 ph for a few weeks.
I have flushed twice with fresh water at 6.5 BUT the run off is still only 4.5 ph. The plant leaves are very droopy but good in colour...Any tips welcome

i would say don't sweat it.. the droopy leaves maybe from all the flushing that you've been doing to her.. i tihnk that sometimes people get freaked over ph really.. if you listen to uncle ben, he thinks its a lot of hype really.. but anyhoos, regardless, so long as the plants overall health looks good, i would just continue watering them from now on out with the ph'ed water and they should bounce back fine.. afterall, the way i look at it, rain waters not perfectly ph'ed at 6.5 or whatever, and look at outdoor plants..
just my two cents...

if they still look healthy mate and you have flushed them out i would think things can only get better from now

add som lime

Ok , how much lime for 10 liter coco do you recomend?

whoa whoa whoa. dont add lime. Test your soil for its ph too, not just the water. let the babies dry out for a day or two and see if they perk. if they are green they are fine, just over watered.

Its coco and it took 100 ltr tap water to bring one 10 ltr pot from 4.5 to 5.5 ph ..

5.5 aint to bad. like my man said just let them dry a bit and get them perky agian and retest agian with whats going in and out. PH really is sometimes over rated but deff not to be over looked. right now my soil is at 5.9 and im not going to mess with it. but if you insist. i have used lime only once and i did a half teaspoon to a gal of water. then agian with the same mix aobut 2 weeks later.

somtimes they can get used to the enviorment and a rapid change like the one you just did will shock them.
slowly raise your ph and they will do fine