What kind of trace elements in the 7-11-27? (It should be
fine for tomatoes as long as it is not oversupplied. The ratio
is ok.) A lot of growers, especially container growers, use
kelp, Planters II, Fertall chelated minerals, and similar to
supply minerals that are not in their main N-P-K source.
A document with symptoms of mineral deficiencies on
tomato plants:
http://4e.plantphys.net/article.php?ch=5&id=289
A document from TotalGro that discusses interactions between
nutrients in the case of oversupply of some nutrient:
http://www.totalgro.com/concepts.htm