Fluid simulation problems I want to do animation which starts fluid at frame 150. I get that by setting offset to -150. but till then it gives this domain with material of fluid. What should I do to do it correctly??
As suggested in comments, you could simply hide it at animation start and reveal it at 150 keyframing its visibility.

To do this you can keyframe the domain object "eye" icon when it must change state (press the i key on it) in the graph editor you can edit this as usual but it will add a "restrict view" channel.

This can toggle visibility on/off by getting values of 0/1 (visible/invisible) as below:



which works like this