Week 5 flower

Needing help with a situation

Currently running 6 plants in dwc (oxypots)
Half way through week 5 in flower and currently having what looks like to be a deficiency in couple of plants

Using shogun line
Bloom a&b
Active sumo boost
Pk warrior (put in half way through week 4)
Calmag was put in as i thought i had calmag deficiency
Silver bullet (hydrogen peroxide)


Room temps 20/21c lights off & 22-25c lights on
Humidity sitting 55%-60% lights on
Humidity 70% lights off
3 fans keeping air movement constantly
Running 630w led
600w hps
Water temps 18-20c
Ec has been at around 2-2.2 but has gone up to 2.8ec as water levels gone down but topped up back to 1.8/2.0 ec after a day (couldn't get to grow room that day)

PH has been dropping, guessing too much nutes in the solution?

Lower leaves are yellowing with brown spots and some tips (see pics)

Have read online maybe a potassium deficiency but my nutes have been high end of ec so surely i wouldn't get a deficiency?

First picture is a leaf off the plant in 2nd picture

3rd picture is a leaf off the plant in 4th picture

The reset are pictures overall


I have just topped up all res's, dropped ec range to 1.2-1.6

PH 5.9/6.0

Your ec is too high.
Sack off the pk booster.. it causes too many problems.
Room temps too low.