Potash deficiency?

Hey guys I'm in week 6 now of beg. Growing indoors with supersoil, however I did eye all of my measurements. (Stupid, I know. I'm getting a good scale for the next batch I'm mixing up today.)

Anyways guys temps stay between 68 and 79. I've got two 600's cooled by outdoor air. Rh: 20-35%. 6 plants, all are displaying the deficiency to some degree.

RIU is not allowing me to post pictures. Trying again in a response.

Well I tried. Couldn't get the pictures on here. Whether it's phone, app or user error I'll never know. Hopefully someone can still help me out.

The leaves turn a necrotic yellow from the outside in while rust spots, which look like burn at a quick glance, form just inside the tips of the leaves. The new growth looks fine it is the middle and lower parts which are affected.

Judging by the charts it looks like potash deficiency, any opinions? Sorry about the pictures folks!

Hi...
A picture is almost crucial. Nutrient burn and P deficiency sometimes look similar but K deficiency is yellowing around perimeter but not necessarily necrosis. I'd bet money that you overfed. Why should you be K deficient in a rich soil and with feedings? Evaluate your protocols. A good organic soil should not need any extra nutrients for a month or so. So probably you should do the nute burn thing...flush and reduce feedings.
JD