Looks like either pH spotting or Calcium deficiency to me. The rust colored spotting is usually Calcium. Lighter colored spotting (whitish) is generally more associated with Magnesium. Judging by your pH at 6.1 I'm leaning towards that being the issue. Healthy soil pH is 6.5, Hydro is 5.8... You're stuck somewhere in the middle, which is an issue. Your biologicals that are responsible for processing and breaking down some of these nutrients need the right pH to keep doing their jobs.
Calcium deficiency looks like rusty spots because of how the element works in the plant. The energy cannot be moved away from the area on the leaf and as a result the chlorophyll literally over heats. Think of it like running out of Oil in your car. Eventually the engine seizes and catches on fire from the heat. The entire cell burns, which is why it is brown.
Magnesium deficiency looks more white because it is an element utilized by the chlorophyll for making the energy. If the element is in short supply the chlorophyll simply dies, which causes the plant to lose its pigment but without the burning. Thus, instead of a "burn" you just get a lighter colored spot from the absence of the green stuff.
That's how I understand it anyway.
I'm iffy with Tiger Bloom. I see a lot of sick plants on that stuff. Personally, I think all you need is the Grow Big and the Big Bloom. There are so many metals in the Tiger Bloom it makes me question the chelators they use to keep it from precipitating. Combined with the perlite (which can hold on to these salts and metals) this could create a different pH in your media than in you are feeding as a result of the build-up's influence.
