# Biphasic system simulation **URL:** \ **Category:** User discussions\ **Created:** [March 5, 2024, 9:28am UTC](https://gromacs.bioexcel.eu/t/biphasic-system-simulation/8506 "2024-03-05T09:28:47Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![SP06](https://avatars.discourse-cdn.com/v4/letter/s/ecb155/32.png) [@SP06](https://gromacs.bioexcel.eu/u/SP06)\ **Post date:** [March 5, 2024, 9:28am UTC](https://gromacs.bioexcel.eu/t/biphasic-system-simulation/8506/1 "2024-03-05T09:28:47Z")
GROMACS version: 2021.4 GROMACS modification: Yes/No Here post your question : I wanted to simulate a biphasic system, so I am following the tutorial of water-cyclohexane system, but I have a confusion here that after placing the protein in water-cyclohexane biphasic system, do I need to proceed from solvation step, then adding ions, etc. as in the lysozyme tutorial? Is the solvation step needed here? From which step should i proceed ? ---
**Author:** ![MichelePellegrino](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/michelepellegrino/32/628_2.png) [@MichelePellegrino](https://gromacs.bioexcel.eu/u/MichelePellegrino)\ **Post date:** [March 5, 2024, 10:02am UTC](https://gromacs.bioexcel.eu/t/biphasic-system-simulation/8506/2 "2024-03-05T10:02:05Z")
Hi, If I understand it correctly, you are at the final step of the tutorial, having a simulation box with the peptide in the upper half and cyclohexane in the lower half, am I right? You can solvate with water by using `gmx solvate` and giving your current system as `-cp`. Basically your “protein” now is the peptide+cyclohexane system, without water. ---
**Author:** ![SP06](https://avatars.discourse-cdn.com/v4/letter/s/ecb155/32.png) [@SP06](https://gromacs.bioexcel.eu/u/SP06)\ **Post date:** [March 15, 2024, 6:16am UTC](https://gromacs.bioexcel.eu/t/biphasic-system-simulation/8506/3 "2024-03-15T06:16:32Z")
Thank you for helping.