So I am working with an Atlas Gravity pH Sensor and in the calibration code the sensor returned plausible pH values, whereas with the code I'm writing I get values that don't make sense. is there some command that helps return the actual ph level?
No. You must compute a value based on the voltage read from the sensor. I see a stated value of 2.7 to 0.2 volts. What numbers are you getting from the analog read?
Which Arduino board do you have ?
The Atlas Scientific Gravity™ Analog pH Sensor / Meter: https://atlas-scientific.com/embedded-solutions/gravity-analog-ph-sensor-meter/.
They say: pH = (-5.6548 * voltage) + 15.509
Put it in a glass of water to start with.
When using it with a aquarium, the differences in grounding can disturb the sensor.
They provide code with calibration and storing settings to EEPROM. That code is hard to chew 
I can not tell if that is good code or not.
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Thank you, the values i get are 427-428
Is the water pH 3.7 ?
Calculation: https://www.google.com/search?q=(-5.6548*(427%2F1024*5))%2B15.509
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using an elegoo uno r3
yes! thats what it reads on the callibration code thank you so much
int pHA = A0;
int led = 2;
void setup(){
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(pHA, INPUT);
}
void loop(){
int pH = analogRead(pHA);
Serial.println(pH);
if (pH < 7){
digitalWrite(led, HIGH);
}
delay(1500);
}
^this is my code, the callibration code is a little longer;
uint8_t user_bytes_received = 0;
const uint8_t bufferlen = 32;
char user_data[bufferlen];
void parse_cmd(char* string) {
strupr(string);
if (strcmp(string, "CAL,7") == 0) {
pH.cal_mid();
Serial.println("MID CALIBRATED");
}
else if (strcmp(string, "CAL,4") == 0) {
pH.cal_low();
Serial.println("LOW CALIBRATED");
}
else if (strcmp(string, "CAL,10") == 0) {
pH.cal_high();
Serial.println("HIGH CALIBRATED");
}
else if (strcmp(string, "CAL,CLEAR") == 0) {
pH.cal_clear();
Serial.println("CALIBRATION CLEARED");
}
}
void setup() {
Serial.begin(9600);
delay(200);
Serial.println(F("Use commands \"CAL,7\", \"CAL,4\", and \"CAL,10\" to calibrate the circuit to those respective values"));
Serial.println(F("Use command \"CAL,CLEAR\" to clear the calibration"));
if (pH.begin()) {
Serial.println("Loaded EEPROM");
}
}
void loop() {
if (Serial.available() > 0) {
user_bytes_received = Serial.readBytesUntil(13, user_data, sizeof(user_data));
}
if (user_bytes_received) {
parse_cmd(user_data);
user_bytes_received = 0;
memset(user_data, 0, sizeof(user_data));
}
Serial.println(pH.read_ph());
delay(1000);
}
Really sorry about the formatting, apparently i still dont have attachment privileges
Please post ALL the code. The errors are in the part you did not post.
// to use the Atlas gravity circuits with
// the gravity isolator board's pulse output
// uncomment line 8: #define USE_PULSE_OUT
// you can use any pins instead of just the analog ones
// but it must be recalibrated
// note that the isolator's analog output also provides isolation
// #define USE_PULSE_OUT
#ifdef USE_PULSE_OUT
#include "ph_iso_grav.h"
Gravity_pH_Isolated pH = Gravity_pH_Isolated(A0);
#else
#include "ph_grav.h"
Gravity_pH pH = Gravity_pH(A0);
#endif
@jremington this is the rest of the code i omitted from the calibration code, it wasnt used when i ran either sets of code, theres nothing else left
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