So it wast only the timer that failed!
Checked kh and it read 4dkh. Considering the amount of vinegar im dosing and the lights been on for so long, its no wonder corals started to bleach. I decided to up KH as fast as safely possible, except corals actually started getting worse. Checked KH again and it still read four. Checked using the test sample in the kit and it also read as 4
Went and got a new kit and turns out my KH was actually sitting on 12. No wonder my poor corals have been getting progressively worse. Tank is also very very white, not sure how many sps will pull through.
Now i really have no faith in test kits. Kit wasnt old and only expires next year.