It depends on your setup and how big your res is.I got a cheap EC meter on Ebay for 20 euros. Seems to work fine. I wasn't going to bother with one either, but from what I've read about Hydro its a needed piece of kit.
It depends on your setup and how big your res is.
with a 1 gallon res, you are measuring your concentration @ the exact value.
Sweet jesus thats a massive res, lolMy res is about 11 gallons so i thought I'd get one. I'm due to go on holidays in a couple of weeks so I made my res big enough so it will last the week I'm away unattended.
I just hope I don't come back and my plants are dead. Can't really trust anyone to come over and keep an eye on them. The less people that know about my grow the better. To many dodgy robbers around here.