Crop King Seeds Purple Kush & Candy Cane - PH Issue or nutrients deficiency

[Nfld320]

Yet another first time grower here reaching out for help...
Back ground: 3 gal pot, 1/3 perlite, vermilite, peatmoss soil less mix, using general hydroponics 3 part solution c/w cal/mag.and basically followed the instruction on the bottles and ph to 5.8-6.0

So I have made it to week five after switching to 12/12 light cycle and I have a major problem that as arose starting in week 4. It starts with Brown/rust spots on the largest fan leaf's and then the tip turn brown/black followed by the leaf begins yellowing and the the leave dries out to a crisp. (On the lower fan leafs it starts on the parts of the leaf that get the most light.) After way to much time I have come to believe that it is a Ca deficiency, From all the pic's I have seen its the closest match, But in my case it starts in the largest fan leaves and not on the new growth like a Ca deficiency. Then I started to think it was a mg deficiency or maybe a P or K deficiency...
But Now I believe that its all of the above caused by my low ph in my soil less medium. I did a flush with 6 gal of 6.5ph water and the water run off is approximate now in the 5.0-5.5 range. (I am using a fish tank tester to read ph levels). I'm at a loss to why my run off water ph is so low and never got up to at least 6.0 after getting a 6 gal flush.
This problem is only effecting my purple kush plants and not my candy cane.
Guys and girls a little help for your brother farmer will be appreciative.
Cheers

 

[Nfld320]

Here is a pic

 

[Alienwidow]

So your this far into flower and your running into problems and you figure its ph now? No. If it was ph thered be signs in veg. My guess would be that its lack of cal and mag. If you arent supplimenting them then your plants will get all kinds of jankey looking. Yellow leaves with rust splotches that die and curl back right? Id get some calmag for the next grow. If you can get some for the next watering you may do a little good, but if you are showing a deficiancy its probably too late to stop the damage, just help slow it a bit. Most guys cut out he calmag for the last two weeks of flower so you have time for a few applications. Now post some of those purple pics for us purple bud hunters.

 

[Alienwidow]

Here is a pic

Oh ya, minor calcium issue. No worries, thats not even bad yet.

 

[Nfld320]

Here so purple

 

[Alienwidow]

Here so purple

Nice! Looking killer man! When you get done make sure to post some pictures of that plant on the site.

 

[Nfld320]

One more

 

[Woyaboy]

Oh ya, minor calcium issue. No worries, thats not even bad yet.

Hey, this is not OP but I have been seeing problems in my lower growth in my 3rd week into flowering. Before that everything looked Dandy. People are saying it's a PH issue, but shouldn't I have seen PH issues MONTHS ago? Why would they suddenly just now be showing up? Basically my leaves are yellowing, browning and shriveling and I am trying to fix this ASAP. I feel like it's Phosphorus or maybe a lil CAL/MAG issue. Like my Kush plant right next to it is looking just Dandy and I've been using the same water just minus the ferts. I just started using Jacks once I flipped to flower though. I have bloom and Citrus Feed.

 

[Alienwidow]

Hey, this is not OP but I have been seeing problems in my lower growth in my 3rd week into flowering. Before that everything looked Dandy. People are saying it's a PH issue, but shouldn't I have seen PH issues MONTHS ago? Why would they suddenly just now be showing up? Basically my leaves are yellowing, browning and shriveling and I am trying to fix this ASAP. I feel like it's Phosphorus or maybe a lil CAL/MAG issue. Like my Kush plant right next to it is looking just Dandy and I've been using the same water just minus the ferts. I just started using Jacks once I flipped to flower though. I have bloom and Citrus Feed.

Theres normal yellowing that happens called seasonal drop sometimes. But lots of yellowing in flower too early providing everything else is on point, can be a sign you either, didnt feed enough nitrogen during veg, or switched directly to a bloom food at the light switch. Lots of fertilizers dont have enough nitrogen or something and the stretch eats all of whats in the soil, then the plant starts eating the leaves to compensate. Either that, or theres too much p and k in there and it poisons it. Who knows, i dont. But all i do know is that in the years of testing when to switch to bloom food ive found that running veg nutes to week three of flower usually will leave you with green leaves, or mostly green leaves till chop.

 

[Nfld320]

So here is my update pic.