Think about what you are saying.
Guy crashes car into light pole. Power goes out, reef dies, do you sue? Driver or electric company? Reef equipment company because the product didn't provide battery back up.
Guy on R2R give you bad advice, you take that bad advice, you kill everything. Do you sue? R2R member or revtree?
Apex notifies you that your chiller is not coming on. Temp is 84 and rising. You rush home, you motor fails in your car. And you don't make it home in time to save the reef. Do you sue? Chiller company for product failing? Car manufacturer? Maybe Neptune for notifying you in the first place causing you to rush hence damaging you car?
Where does it end?
I have thought about what I'm saying because I understand how civil laws, as well as criminal, work.
The power went out because of the driver. You sue the driver for damages. If the backup battery you installed for the reef malfunctions- key operative word- because of the driver, you still sue the driver.
If damages occur at the advice from someone, they can't be held responsible. You have no case in negligence because you won't be able to show a duty of care. However, if they were paid for that advice and that is service they provided, you follow the advice, and wipe out your tank, they can be held responsible. Then, and only then, do you have a case.
Hopefully you set up your Apex to turn off heaters, you have a fan installed and it kicks on. Anyways, you probably don't. So you take the chiller company to task for the damages that may have occurred to your reef. Your car has nothing to do with the initial malfunction of the device. Then you take the car company to task for malfunctioning within warranty.
You can only take a company to task within a reasonable time of buying a device. Unless it says can last such and such long. If, however, it doesn't, you take the company and you hold them responsible. Whatever the reasonable time outside of a warranty remains to be determined. If a device malfunctions in 10 years, and only has a 1 year warranty, there isn't much you can do. Also, statute of limitations comes into play. Another thing to consider is your state laws.
What do you mean it back siphoned? Tank water got back into your dosing containers? If so, the only way this could have occured is if you installed your lines below the water (which is a big NO NO).
If that occurred, then the device OP was using wasn't used in a proper manner in accordance with setup. At that point, it becomes clear the responsibility lays squarely on OP's shoulders.