Measure water into a small microwave safe bowl. Stir the gelatin into it. Set it aside while you make the other preparations.
In the bowl of a stand mixer combine the cream, powdered sugar, vanilla, and salt. Beat with the whisk attachment on high for 1 minute. This is the time to taste and adjust for additional sugar if desired)
While the mixer is running, microwave the gelatin mixture for 20 seconds or until the chunk of gelatin turns to thick, syrupy liquid.
Continue beating the cream on high while slowly pouring the gelatin into the cream in a thin stream. Beat until stiff peaks form. Set cream aside while you prepare the berries.
Combine half the raspberries with 2 cups of the diced strawberries. Stir gently to combine. Pour fruit into a decorative dish to create the first layer.
Layer half of the whipped cream on top.
Combine all of the blueberries and blackberries and pour on top of the whipped cream.
Layer the rest of the whipped cream on top (you can save a bit to garnish the top of the salad if desired.)
Combine the rest of the raspberries and diced strawberries and pour into dish for the last layer. Garnish with additional whipped cream and berries if desired.