grandvapor
Active Member
Calibration solution is only like $10 for a small bottle which will last a long time. I just pour a little into the cap and go from there. Don't put any back into the bottle though to avoid any contamination. There may be some home remedies to create a known ph solution, but I would not know if they were accurate or not. I picked mine up at the local shop, but you can order online as well. I calibrate my pen every week or 2 or at least check it to make sure it's reading correctly.
Edit: Mind telling me what kind of solution you found locally to calibrate your meter? I found some 4.01 General Hydroponic solution but you'd have to pour at least a few ounces into your cup to get a reading on the pen, and the GH solution seems pricey.