Help my 2 plants are suffering.

[Don't Fear the Reefer]

Problem: Plant 1 Godzilla Cookies, overall yellowing of leaves, starting from the bottom up, black spots on leaves, reddish brown blotches on leaves, lower leaves easy to pluck off with slight pull.
Problem: Plant 2 Slaughtered Lamb, overall yellowing off leaves, black spots and brown patches on leaves, wilted leaves will not pluck off easily.
Medium/grow method: both in Plant Magic Soil Supreme, a peat based soil.
Feed and supplement used: Plant Magic Organic Old Timer feed (included a picture of schedule. Feeding half dose, EC range from 0.550 EC to 0.850 EC, using a feed, water, water schedule, using a hand pump sprayer, feeding and watering to run off.
Water source: Tap water dechlorinated for 24-36 hours 0.148 EC, PH 7.01
Strain and age: Plant 1 - Godzilla Cookies age 48 days old, Plant 2 - Slaughtered Lamb 48 days old.
Climate: 25-26 degrees C temp , 55% RH daytime, 20-21 degrees C temp, 55% RH nightime.
Light used: Viparspectra KS3000, 300 watt led grow light. 18 hours on/ 6 hours off
Additional Info: Godzilla Cookies in a 3.8 litre pot, Slaughtered Lamb in an 8 litre pot. Godzilla Cookies started showing symptoms just over two weeks ago, started with an overall yellowing, from the bottom up. Slaughtered Lamb started showing symptoms just over a week ago, started with reddish-brown spots on leaves.
I'm not PH'ing my water or nutrients as it was recommended not to, as the soil is PH buffered and the nutrients are organic liquid feeds. I'm supposed to be feeding the soil? Don't know if this is correct.
Here are some pictures for you.
Plant 1 - Godzilla Cookies

Plant 2 - Slaughtered Lamb

Thanks for any help. I really hope I can sort out these issues, as I have loads of the nutrients left.
A picture of the feed schedule

 

[Badfinger]

I'm definitely not an expert. But it sure looks like a calcium deficiency.
How to fix Cannabis Calcium Deficiency (Ca) Pics & Symptoms (growweedeasy.com)

 

[Talonxracer]

I would ph adjust the water regardless, I have seen these so called self-adjusting ph lines have issues if you do not start with properly PH'd water

 

[Don't Fear the Reefer]

I would ph adjust the water regardless, I have seen these so called self-adjusting ph lines have issues if you do not start with properly PH'd water

I will do now. Thanks for the reply.

 

[Don't Fear the Reefer]

I'm definitely not an expert. But it sure looks like a calcium deficiency.
How to fix Cannabis Calcium Deficiency (Ca) Pics & Symptoms (growweedeasy.com)

It does look like it from the pictures, thanks.

 

[Don't Fear the Reefer]

Hopefully some experts chime in.
I do appreciate the replies.

 

[FarmerJake]

Do you have a way to check soil ph?

 

[Talonxracer]

Are you ph'ing your water on non feed days?

 

[Don't Fear the Reefer]

Do you have a way to check soil ph?

Not at the moment, ordered a soil ph meter, should be here soon. Thanks for the reply.

 

[Don't Fear the Reefer]

Are you ph'ing your water on non feed days?

No, I haven't been, well I did yestereday and it was 7.01 PH.