Arduino Uno Aquarium heater/cooler

Projects Programming
4

is this what you are attempting?

if(temperature < 23) {
    digitalWrite(RELAY1,0);
    digitalWrite(RELAY2,1);   
 }
 if(temperature == 25) {
    digitalWrite(RELAY1,1);
    digitalWrite(RELAY2,1);  
 }
 if(temperature >= 26)
   {
   digitalWrite(RELAY1,1);
   digitalWrite(RELAY2,0);
}