pH and PPM meters

go to amazon look up bluelab no doubt will find what you need there. That is where i got mine

I use a TDS meter by Oakton.
In soil, if you admix some powdered dolomite, never a pH worry. cn

http://www.amazon.com/HM-Digital-PH-.../dp/B00132G102

http://www.amazon.com/HM-Digital-TDS...eywords=tds+ez

these are what i got and both stay calibrated perfectly. i only recalibrated each twice so far and both times they were barely off calibration. i recommend both as i spent a lot of time making sure i can get something reliable without breaking the bank.(check ebay you could probably get it cheaper, i just put these 2 links so you'll know what they look like.)

I second the blueLab. Never had a problem. It even reminds my stoned ass to re calibrate it.

http://www.ehydroponics.com/blue-lab-ph-pen.html pH Pen 84.00
http://www.ehydroponics.com/blue-lab-ppm-pen.html TDS Pen 70.00

Go to ebay you'll find plenty of them for $10 to $20 and more.

For this kind of equipment, "low cost" and "quality" do not go hand in hand. For your ppm meter, I will say that the BlueLab truncheon is hands down the best tool on the market.

They dont need calibration and they carry a 5 year warranty. It's a probe thats coated in resin with a waterproof plastic covering. You can drop it into your reservoir and it'll be fine. You can drop it on the floor and it wont break. We actually had a bluelab sales rep come in and he was just tossing the things on the ground. They're indestructible. This is one part of growing where you should try not to skimp. Pay 110 for the bluelab, instead paying 30 to 40 time and time again for low quality meters

does the TDS meter do both PPM and pH? I would like in all in one if possible.