I'd suggest a lack of nitrogen. Or low nitrogen relative to other nutrients creating an imbalance. Although you did say the new tips are yellow and this deficiency tends to show up on older leaves first. The epsom salts is magnesium sulphate, i'm not sure how an excess is displayed or how to correct it. The extra potassium shouldn't be a problem.
The Ph is a tad high but not really over the top. Quite acceptable really.
I'd try a liquid fertiliser with a high nitrogen content on one or two plants to test if it is a nitrogen deficiency then go from there. I say liquid because it will act faster esp if you apply it to the leaves.
Another possibility is iron deficiency. This is characterised by newer leaves turning yellow so may be the problem. If you decide to fertilise with the liquid fert, ensure it contains trace elements.
The problem with adding things individually, as opposed to using a complete fertiliser, is that it can upset the balance. Too much of one can reduce the availability of another.
I don't like the meter type Ph test kits as they seem to be a bit inaccurate. I prefer the chemical one.
Here is a handy site for future reference regarding nutrient deficiencies in plants. (Tomatoes are used here)
http://www.plantphys.net/printer.php?ch=5&id=289

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