I think there is a reason Alde has the pump method for changing the Glycol, I don't think gravity is going do drain anything except the Alde unit itself, so you end up NOT doing a 100% exchange. (View Post)
The recommended fluid is non toxic (or less toxic), lots of auto antifreeze is OK for aluminum, but most are toxic. The danger is contamination of the potable hot water if there was a malfunction. (View Post)
You don't want to mix incompatible "antifreeze" fluid rather it is your vehicle or Alde. Maybe the more important reason to ONLY use the recommended glycol is the toxicity of most auto anti… (View Post)