Rather than talking about "a grand trine in Water," why not try interpreting the parts separately... "Saturn in Pisces in the 5th House" means.... and using the interpretations of the planets, rather than the astrological jargon, see how each of these parts might interact with the others.
Maybe use 4 or 5 keyword-combinations for each planet to get a feel for the possible meanings/manifestations, then see how each fits with the others.
What is the nature of Water? What does the 1st, 5th, and 9th house Triad deal with? -- the Water trine is located in this triad.
You also need to take into account the T-square focused on Sun with Moon-Pluto as its base. The T-square does not emphasize a Quality (all 3 planets in same Quality) as is normal. But...Moon and Pluto are Fixed; Sun and Moon are in Earth.
This structure -- Grand Trine with Sun at the Bridle of the Kite, tied into the offbeat T-square with Sun at its focal point clearly points to the importance of the Sun in this complex. He participates in two interlaced and interacting complexes (formations), and is the key figure in both.
A kite can't fly without a bridle. It sails off into the wind with no control, and snags in the nearest high tree. Saturn acts as the tail of the kite. What is the function of the tail? (cf. "sea anchor"...a device used for "keeping her head into the seas" in heavy weather by producing drag.)
What is the nature of a Trine aspect? What is its dynamic? The books mostly say "ease, talent...". I would offer you "momentum, accretion." I suggest you go to http://en.wikipedia.org/wiki/Lagrangian_point in order to understand how a Grand Trine operates in the physical universe. Note that the baseline Sun-Earth is common to the two equilateral triangles with their apices at L4 and L5. What happens at these points? https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTVkpmVaU2rgXovGXN3iTseYI4as-xKSQP6MUIv9rCqQEYS4zlbTA
The Grand Trine, although composed of the "easy, beneficial" trine aspect, was seen by the old astrologers as "not so good:" reason, it inclines to a condition of stasis. Things don't go anywhere. Look what happens to space dust and asteroids that fall into L4 and L5. The Sun, at the Bridle of the Kite (and focus of the T-square) provides a very productive way out of this situation. He is supported by two sextiles, and energized by two squares.
P.S.: Isn't it funny how Venus, who is Lady of the Horoscope, sits directly on the Horizon, in exact square to the conjunction of Uranus-Neptune (squaring their midpoint) which sits right on the IC...a dominant configuration in this chart. I wonder what it means? Whatever it means, it is the most highly dynamic and powerful feature of the chart: these planets are Angular...the square itself is Angular and involves the Lord of the Ascendant. The signs involved are Cardinal.