Flip level goes down

[Waqar]

Hi, 

I have been working on a flip simulation.Its basically a tank. At very initial frames, water level is what I need, and water is almost static as I want.  But as any object interact to flip, flip starts getting natural waves and all, but It is also Loosing its initial level and going down slowly, which should not happen. Water level shouldn't go down. Please, anyone help me to find the problem. All solutions are welcome. 

[Jesper Rahlff]

post a hip file showing us what you have tried to fix the issue and I am sure you will get lots of help

[Midasssilver]

Conservation of volume is a classic issue for flip sims. Usually you counter that by reseeding enough particles to keep the divergence of the simulation at 0.

[awie12]

I think you need to lower your particle seperation. I kinda experience that

[Waqar]

Hi, thanks for replying. I finally found a solution. If I level up particle size slightly from value of 1.0, like 1.2, it maintains the level. Value of 1.0 requires very less particle saperation, as awie12 told to decrease particle saperation. What I did, actually opposite of what he told, because lowering particle saperation increases time(wasn't possible on my small workstation) , but gives fine results. 

As Midasssilver told, it is also a solution, but I needed my water surface very flat and smooth for initial frames, so I kept particle configuration to Grid, instead of tetrahedral. Seeding particles was giving solution, but creating slight noise on surface. 

Thanks everyone for your suggestions. It really helped me.