# define waterLevelSensor A0
# define pumpRelay        9

# define emptyLED A1
# define fullLED  A2

void setup() {
  Serial.begin(115200);
  Serial.println("Pump Whirled!\n");

  pinMode(waterLevelSensor, INPUT);
  pinMode(pumpRelay, OUTPUT);

  pinMode(emptyLED, OUTPUT);
  pinMode(fullLED, OUTPUT);

  setupPump();
}

# define FULL   924
# define EMPTY  100

bool okToPump = false;
bool tankOK = true;     // pin 5 might say tank not OK to pump from

// initial state of 2nd pump
void setupPump()
{
  int waterLevel = analogRead(waterLevelSensor);

  if ((waterLevel < FULL) && (waterLevel > EMPTY)) okToPump = true;
}

void loop() {

  int waterLevel = analogRead(waterLevelSensor);

// proxies for the two float switches
  bool ohTankFull = waterLevel > FULL;
  bool ohTankEmpty = waterLevel < EMPTY;

// what the float switches would say
  digitalWrite(fullLED, ohTankFull);
  digitalWrite(emptyLED, !ohTankEmpty);

  if (ohTankFull)
    okToPump = false;

  if (ohTankEmpty)
    okToPump = true;

  digitalWrite(pumpRelay, okToPump && tankOK);

  delay(100);
}