Duh… I’m dumb. I can’t get the Active IPO to do anything. The Time IPO works but you can’t have it touch or go below Y-zero, so the fluid still moves. Somebody (and I can’t remember who and can’t find it in a search either) wrote a Perl script that makes a new batch of .gz files and renumbers them. I’ll keep searching and see if I can find it.
It would depend on the type of fluid animation that you are making.
If you are just animating a water sphere splashing onto the ground you can use the Fac-Time (Time Factor) IPO curve. It operates a little differently than a Time IPO.
Note that you must add this FluidSim IPO to the domain object.
So with your domain object selected, add a Fac-Time IPO, set the first key at (X,Y) = 1,0; and then your second point at 25, 1 (to delay the water drop from falling until frame 25). TAB out of Edit mode for the Fac-Time IPO curve (points should appear as white dots) press [t] and set the IPO curve to ‘Constant’. After you bake the FluidSim, you should see the fluid drop suspended in space until after frame 25.
If you want to control a faucet turning on and off, you need to add the ‘Active’ IPO curve to the Inflow fluid object. (The one ‘generating’ the fluid).
So, if that object is an IcoSphere, select it first. and then add your ‘Active’ ipo.
Create a ‘Constant’ IPO curve Type as described above.
Note that anything equal to or less than zero is OFF, anything above zero is ON.
(So it acts as a sort of On /OFF switch in the sense of generating fluid, but does NOT suspend/influence time or affect the dynamics of the fluid animation)
Hope that helps, maybe if I have some more time I can write a more thorough description.