Thoughts on my deficiency or water issue

[Rrains007]

Overall the plants are healthyish based on the first photo but you can see the leaves from the bottom half down are struggling. They are week 5 in veg. Temps are 78. Humidity is 70 day and 55 night. I'm running house and garden line with adding cal mag because my ro system took that out. I'm using well water which is hard water and has sulphur. I hooked up a pre evolution 200 system that filters the water which then runs through the r.o system lastly. I'm about to start hauling water because I think this is a water issue. I think I'm taking out important things out of the water that shouldn't be filtered out. Any thoughts on this? Thanks!

[Rwise]

Take a look here, find your symptom, looks like mag deficiency.
RO water is also slightly acidic, there is not enuf stuff in it for a PH meter to test with. Hard water may not be bad, but the sulfur can drive the PH down (note our girls need some sulfur). Epson salt will add cal/mag back to the water, just make sure its not scented.

[Rrains007]

Rwise you're saying my ph meter might be giving a false reading? I've been running my ph between 6.2 and 6.3.

[ChadWestport]

When was the last time you calibrated it? I had my blue lab pen give me wrong readings but unfortunately it was only in the 6.4-6.1Ph range. It calibrated fine at 7 and at 4 but when I double checked my "6.3" Ph water with the drops, it was off by enough to make an issue. Not sure how long I fed that way, but it did cause problems. I cross referenced its reading with the drops from very acidic to very base, it was only that small but important range that provided an askew reading. So, anything is possible really.

[Rwise]

The one I tossed out did not read well, what I have now gets calibrated monthly

[BaccaRacca]

if you are using a peat/perlite mix you may not need to go through all the folderal with the RO filtration and Cal/Mag issues. As you mentioned the RO process is taking stuff out that you have to add back in, so why take it out in the first place? The high acidity of peat buffers the alkalinity of the hard water. Roots find the proper acidity level between the acidic peat, leach water and perlite. The plant does the work essentially, so you don't have to. It's a reliable method that greenhouses, nurseries and old hippies like myself have been using for decades. Here's a photo showing how the roots find their zone in the mix:

[Bengfan]

I have used nothing but ro water for years now with zero problems. You need to add a little calmg to get the ppm up to 150 or so and then you are good to water or feed. Also, there are nutrients made just for ro water use. The first that comes to mind is made by Jacks who has been making high quality nutes for years. Good luck!!

[Rrains007]

ChadWestport it's a brand new one so I calibrated it right away. With the blue lab I always thought you needed to recalibrate when the 7 and 4 display is no longer viewable

[ChadWestport]

ChadWestport it's a brand new one so I calibrated it right away. With the blue lab I always thought you needed to recalibrate when the 7 and 4 display is no longer viewable

I'm not sure of an internal message to recalibrate it, but the directions suggested every 30 days or something, so that means I checked it about every 60 days... lol.. A new one should be good, did they provide the little calibration packets in the box too? Mine worked great for about a year. The battery signal is on, meaning low battery but it has kept working. My plants started showing issues but everything was spot on with suggested levels and such. The plant was telling me Ph but the pen said, don't worry. Then I decided to double check the pen after calibration showed it to be perfectly accurate. Double checking with the drops is how I discovered the oddity. Still haven't replaced the battery though... smh