ph pen

Hey guys really quick question Just got a ph pen trying to calibrate but don't know which water to use as the instruction book says to use distilled water but the ph solution packs they sent say to mix it in deionised water so ye which do I use distilled or deionised water really hate...

What do people think of these meters mine is fucked so need a new one and these are only about £60 on eBay and the ones from my hydro store are the same price and probably shit obviously I know they only last if stored properly would appreciate anyone's opinion thanks

Hello! I had been using a liquid pH test kit for years and finally decided to splurge on a pH pen. It is definitely more convenient than the drops and I am glad that I did it. I do have one question about the pH pen, though, and I am hoping that some of you with more experience can help me out...