Change float double and 4 bytes values. C#

I am currently creating a program which can modify addresses, but I can't seem to get it working.

I have multiple addresses in a Cheat Engine file but I want it to be editable from a C# form.

The things I've tried are this:

myMemory.ReadProcess = pname1[0];
myMemory.Open();
int[] a = { 0 };
int OUtput;
myMemory.PointerWrite((IntPtr)0x01055E70,BitConverter.GetBytes((float)300), a, out OUtput);

To get the process I did this

Process[] pname = Process.GetProcessesByName("Microvolts");
if (pname.Length != 0)
{
    pname1 = Process.GetProcessesByName("Microvolts");
    procHandle = OpenProcess((0x00010000 | 0x00020000 | 0x00040000 | 0x00080000 | 0x00100000 | 0xFFF), false, pname1[0].Id);
    label1.Text = "Running";
    timer1.Enabled = false;

}