Do not install MAC OS on an SSD drive. How to decide?

Question

macOS

Macbook Pro 13' MID 2012
Instead of a regular HDD, I installed an SSD drive INTEL 535 Series SSDSC2BW256H601 256GB, 2.5", SATA III
The regular one replaced the DVD in Optibay. I planned to install the system on an SSD, use the HDD as storage.
1. During the first installation, the system did not see the SSD , HDD only
2. Temporarily installed the OS on the HDD
3. Created a bootable flash drive with OS High Sierra
In boot mode, neither Disk Utility nor the installer sees the SSD
In normal mode, Disk Utility sees the SSD, but does not allow it to be formatted: "Do not failed to disconnect the drive."
Sometimes in the corner of the screen there is an inscription: "The disk was not ejected correctly". That is, the SSD drive is disconnected.
What could be the problem?

Answer 1

Optibey does not know exactly about sata3, there is a problem with enabling trim on ssd, there are problems with poppies and ssd-sandforce controllers. And an even bigger problem with all this and the latest version of Sierra...