First Grow - Seeking Advice for ventilation - have grow tent & cooltube, now for the rest

Also, I just measured the pH and EC of my tap water that I let sit for like 36h:

My pH pen is not calibrated anymore, despite storing in KCl 3M solution, so now I have that to deal with that headache.
TDS meter said 95ppm, and wikipedia told me that was "moderately hard". Would I need CalMag in a situation like this?

Nic Barlor said:

Also, I just measured the pH and EC of my tap water that I let sit for like 36h:

My pH pen is not calibrated anymore, despite storing in KCl 3M solution, so now I have that to deal with that headache.
TDS meter said 95ppm, and wikipedia told me that was "moderately hard". Would I need CalMag in a situation like this?

Click to expand...

If your water is hard then there should be plenty of calcium and magnesium in there already. I live in a hard water area and grow in coco (which is known to cause cal deficiency for some) and although I do have a bottle of cal mag handy I don't really need it, I do give them a low dose in early veg and when re using the old coco.
I just found out how important cacium and magnesium are for us humans too! Shouldn't be surprised, we are all living things after all.
Anyway, sorry my reply is late.
Happy growing.