yellowing leaves - follow up

[Not-a-cop]

Hi - this is the link to my other sick plant, seems this time im not doing so well!! https://www.autoflower.org/threads/hallo-yellowing-leaves-on-1-of-2-plants.83166/#post-2425149

Problem: So i have 2 Fast buds star dawg growing in the same tent, under the same lights, same conditions and same nutrient schedule, the one that was "well" last week when i posted originally is now looking "unwell" and i'd like some advice please
-Medium/grow method: Soil - Biobizz All Mix
-Feed and supplements used: Biobizz Biogrow & bio bloom per below schedule + 1ml/l vitalink calmag + misted every day with 1ml/l calmag solution

Note: this "was" the schedule, after finding out the biobizz it too hot for autos, i cut down to plain water and 1ml/l calmag plus a plain water spray/mist daily for the last 5 days, is it just hungry?.

-Water source: tap water, 50ppm on 640 scale is around 0.04EC, there's not a lot in it
-Strain and age stardawg by fast buds, germinated on 27th march so around 5 weeks
-Climate: lights SP250 18hrs kept at a temp of 25 - 27 celcius, lights off temp drops to around 16 celcius
- Light used: mars hydro sp250 18/6
-Additional info: symptoms appeared quite quickly, now spreading to the newer but not brand new growth, it is approaching the bud sites now and im concerned that it will not last the remaining 4 - 5 weeks it needs to, this plant looked good only 5 days ago.

@Mañ'O'Green i'd really appreciate your input on this if you can please?

 

[Cannagus]

Looking at a leaf chart it looks to me like the closest match is low K (potassium) good luck I hope it turns around for ya

 

[Mañ'O'Green]

Why are you adding Cal-Mag? You have a full blown lock-out now.

You need to learn how to fertilize:

Tutorial - A word on Nutrients

The proper use of “salt” based fertilizer to grow Auto Flowering Cannabis. Salts: Natural and man made any chemical compound formed from the reaction of an acid with a base, with all or part of the hydrogen of the acid replaced by a metal or other cation. Learning how to use salt based...

www.autoflower.org

 

[Not-a-cop]

thank you. could i try flushing the soil or is it even worth it?

i was adding calmag on the advice of a book called "Marijuana Horticulture The Indoor Outdoor Medical Growers Bible". In it the author states that you should add calmag if your water has less than 50mg calcium per litre, i looked up my local waterboards website and they report that i have 12mg/l, so i thought i was doing the right thing

bugger.

extract:

my local results:

Calcium Hardness (mg/l)	13.3
Magnesium (mg/l)	0.9
Potassium (mg/l)	0.4
Calcium (mg/l)	11.6
Total Hardness (mg CaCO3/l)	33.0

 

[Bill.de.Cat]