Quote Originally Posted by stinkyattic
grey, how long do you find that your promix lasts before you notice a drop in pH vs. what it was when the stuff was fresh? I find that it's pretty much good to go for the first 6 weeks with no hassles, but will start to creep down and makes it out of range after a couple months.
This may sound like a really crappy answer but I didn't use to check soil ph as I didn't normally have a problem. But when problems appeared this cycle I finally got around to checking it after it was 5 weeks into flower and it was coming out .6 or .7 below what it went in. In at 6.5 or 6.4 and now runoff is 5.8.

Well, 5.8 woun't hack it with a soiless medium as anything below 6.5 and you start locking out it would appear. It's too late for this crop, but when I watered last time I ran 7.0 water with about 150% runoff. Next time I feed I'll check again. WHOOPS, I won't be feeding these ladies again, but when I water again I'll check runoff ph. (If I water again). I'm watering less often as these are not the best ladies I've produced. They are now at 45 days and about done (Cheese). I won't know the impact of my problems until I measure yield but I've found many times they look worse than they are and yield sometimes suprises me.

So, 28 days veg, 45 days flower means they've been in the ProMix 73 days. I also noticed my mom's had 5.8 runoff last time I checked. One of them has been in a 2 gal container for several months so I suspect a salt build up. Interesting note: As an experiment I'm keeping the moms in the 2 gal pot to see how long I can keep it going before having to transfer. The last time I thought I had to transplant I ran some clearex through them and they recovered. NEW GROWERS: Please don't think you don't have to transplant THIS IS JUST AN EXPERIMENT.