Help! Rust spots spreading...

I had what, after some research on the forums, I thought was a problem with calcium and magnesium a few weeks back so I got some Cal Mag to sort the issues. It seemed to help for a bit but then things started gradually going down hill again.

I had a look at my girls this morning and things are getting worse! There are rust spots all over the shop. One of my girls is particularly bad.

I thought rust spots were a result of a calcium def but I have been treating them with Cal Mag. Does anyone have any suggestions as to where I am going wrong?

Also, one of my girls is developing a lot of deep purple leaves.

3rd week of flower. 600W HPS. Day temps around 79℉. Night temps around 65℉. Feeding with BioBizz Grow, Bloom and Top Max.

It's Sour Diesel, by the way.

Too much P too early...very possible pH problem with the low micro's showing too. Excess K levels - early use of bloom feeds again.

NO bloom feeds till week 3 of bloom! FUCK what the makers tell you! Then mix 50/50 and at week 4 go full on bloom.

It is a wonder how often I see this exact same problem from Bio Bizz.....US and EU......

Thanks for the reply. So cut out the Bloom for a bit? What do you mean by low micros?

That's when it started on mine. Maybe a tad earlier. What medium are you in?
I grow in pro mix and use tap water which I was told was fine to use and no need for ph'ing because pro mix, nutes etc. I had never tested my water for EC or Ph. I finally bought ph and ec pens
My tap water ph's at 8+ and although after adding nutes it's ok, on its own it was too high.
I flushed with 6g ph'd water (3g pot) and then gave a light feed. Fixed the problem.
That's just my experience. Ph matters.

You're situation is pretty similar to mine except I have been adding a very small amount of white vinegar to my water to bring the Ph down. I'm growing in Allmix.

I will try this and let y'all know how I get on.

Wee update:

I flushed them with PH'd water, gave them a little feed and held back on the Bloom. Some of my girls responded better than others.

One really appreciated it, two look at bit better and one, although better, was obviously affected worse because it still looks a bit worse for where.

I'll keep an eye on her and the other girls and keep y'all posted.

Been a few days now and all my girls are looking like they appreciated the flushing.

Dr. Who said:

Too much P too early...very possible pH problem with the low micro's showing too. Excess K levels - early use of bloom feeds again.

NO bloom feeds till week 3 of bloom! FUCK what the makers tell you! Then mix 50/50 and at week 4 go full on bloom.

It is a wonder how often I see this exact same problem from Bio Bizz.....US and EU......

Click to expand...

I wait till week 4 to hit em with pk personally feel like any earlier hurts them more than helps them by a long shot