Implementing MIDI Control Change for “Tsunami Wav Trigger”?

Using Arduino Audio
16

What do I need to do?

Don't use so many spaces in between code lines, that won't stop it working but it will look nicer.
All the sound generators I have seen do not use banks 0 to 4 to generate different sound they use more.

I am not sure what you are trying to do because changing the bank will only make a difference to the timbre of the note when you change the "instrument" with a program change. You don't seem to be changing the instrument just the bank, that in itself will do nothing until you change the instrument. However, this code should sort out the attack and release parameters at least.

Not only read up how to write code but also what MIDI messages do, because unless you know what messages you want to send it is impossible to write code to send them.

int channel = 0;
int releasePram = 18;
int attack = 18;

void setup() {
  // Set MIDI baud rate:
  Serial.begin(31250);
  midirelease(channel, releasePram);    // =500ms
  midiattack(channel, attack);
}

void loop()
{
 // midiattack(channel, attack);   // only send it when you need to not hundreds of times a second
 // midirelease( channel, release ); // only send it when you need to not hundreds of times a second

  // Play notes in banks 0, 1, 2 and 3
  // (all on channel 0)
  //
  for ( int bank = 0; bank < 4; bank ++ )
  {
    midiBank( channel, bank );

    // play notes from G-3 (0x43) to G-4 (0x4F):
    for (int note = 0x43; note < 0x4F; note ++)
    {
      noteOn( channel, note, 0x45);
      delay(1000);
      noteOff( channel, note, 0x00);
      delay(1000);
    }
    delay( 1500 );
  }
}

void midirelease ( byte channel, byte pram)
{
  midiMsg(0xC0 | channel, 0x48, pram);
}

void midiattack ( byte channel, byte attack)
{
    midiMsg(0xC0 | channel, 0x49, attack);
}

void midiBank( byte channel, byte bank )
{
  // set MIDI bank LSB
  midiMsg(0xC0 | channel, 0x20, bank);
}

// plays a MIDI note. - restrict note and velocity to a maximum of 7F
// Send a MIDI note-on message.
void noteOn(byte channel, byte note, byte velocity)
{
  midiMsg( 0x90 | channel, note & 0x7F, velocity & 0x7F );
}

// Send a MIDI note-off message.
void noteOff(byte channel, byte note, byte velocity)
{
  midiMsg(0x90 | channel, note & 0x7F, velocity & 0x7F );
}

// Send a general MIDI message
//
void midiMsg(byte cmd, byte data1, byte data2 )
{
  Serial.write(cmd);
  Serial.write(data1);
  Serial.write(data2);
}