Confused about coco

[golfnrl]

Today is transplant day for my seedlings. They are going into their final home. So I need to get this dialed in. This is my first grow in coco and I've read a lot about it and also watched some videos. I'm confused about PH/PPM/EC. I'll be using the autopot system with a 12L rez. When I mix the nutrient solution the EC going in gets out of whack. Target PH 5.5-6.5. Target EC 1.2 At the proper PH the nutrient solution has an EC about twice my target range. I can lower the EC in my nutrient solution by adding clean water. The confusion is this, if I dilute the nutrient solution to lower the EC does that also lower the nutrient strength? Seems to me it would. Also, I'm confused about whether I try to control the PH or the EC in my rez? Controlling the PH shouldn't be a problem as I have Blue Lab PH controller for the rez. The EC I have no idea. I must not be asking the right questions as google and the GWE search engine have yet to give me info that makes sense to me.

 

[Ckbrew]

Yes, if you add plain water to the mixed solution it will dilute the nutrient concentration. I would focus on the pH. Set your EC when you initially make the solution. If it is to high add some RO water to bring it down but don't use straight RO water. Honestly I don't bother with the EC readings. The pH will drift in the res but you say you have a controller. Someone here had an issue with pH controller. Malfunction of some kind causing an entire liter of pH down to be added to the res. You can limit potential damage by restricting the amount of pH down available to be added. I mix what I will be using on the same day, sometimes mixing 2 days worth of solution. When plant problems pop up, pH is the first thing I check to rule out problems. Coco usually needs more cal-mag. I run it all the time except in final flush week.

 

[UndergroundFarmer]

I haven't used an autopot system before so there are details I'm not sure about. I have grown in coco feeding manually though. It seems that EC will increase slightly every time the Bluelab controller adds pH Up or Down. 600 TDS or 1.2 EC is right for small plants in veg, 1.6 for larger ones and 1.8 and higher for the peak of flowering. I'm a bit skeptical about the need for a pH controller in anything but a large recirculating DWC setup. That's also a pretty small reservoir and pH fluctuations may be getting overcompensated for, driving up the EC unnecessarily. You might want to see if there is a way to adjust the Bluelab so only the minimum amounts of pH adjusters go in with maximum time before it can add more. If you can't make it work, you may consider pulling the Bluelab and adjusting pH manually every time you fill the reservoir. Others on this site use autopots in their grows and can probably offer better advice.

 

[gbauto]

Good advice.
Anytime you add ph buffers, it will increase the ec because you're adding either phosphoric acid or potassium carbonate to lower or raise the ph.

 

[Smoklahoma]

That would be me. I can definitely tell you that a ph of 2.0 for 12 hrs kills them quickly.