Wtf is this?!!!! Rust?

Can anyone help? Critical Mass auto, week 2 flower. 12/12 hps 400watt. 80f. botanicare pure blend pro Bloom, pure blend Liquid Karma. Had been feeding a half gallon with 10ml every 3 days, and watering on the other 2 with PHd water. Had been using a Brita filter and used it for too long i think, is it possible metals bled out into my water from the filter? I bought a ppm meter and ph meter. My brita water is 110ppm, and 5.9 pH. I realized i wasn't compensating for the pH going down when adding nutes so I bought a pH buffer as well, adding that I watered today after flushing and not watering for 2 days, with 1100ppm water with nutes at a 7pH to bring my pH up. I've tried to read and find info on ppm's but my runoff has sediment of old R/O and is making my R/O ppm look like 3500....so Im guessing just read the soil ppm? AGHH!!!! Help.

-Z

sorry, the ppm of the brita water is with a new filter.

look like cal/mag deficiency to me

I forgot to mention. When i flushed i watered with epsom salts in their because thats what i thought initially

If using epsom salt. You are not flushing. Epsom salt is magnesium sulfate. Great for mag though. It looks like phos, nitrogen, and molybdenum deficiency. If it were cal def. There would be red circular spots. If it were mag def. The edges and tips would be bright yellow. When its blotchy its nitrogen and phos. Nitrogen def will cause chorophyll def which in turn causes molybdenum def which starts out as a blotchy rust and eventually turns a greyish purple. Light bleaching can cause chlorophyll and molybdenum def too.

Add some more nutes and a little green sand too. If doing soil. Look into super soil and compost and teas.

I had the exact same prob with my critical mass auto grow earlier in the year. I tried epsom salts which didn't seem to fix the prob, tried adding more bloom nutes and still couldn't fix it. I ended up finishing the grow with a lot of dead brown leaves that consumed the entire plant. Still got about 2oz good smoke per plant tho. I've just started another critical mass grow but this time i'm using canna prof soil and canna nutes. So far so good, they're in their 4th week now and look really healthy. Hope you get it sorted please post an update if you find a solution