Six months is more than I've ever left a tank without somebody watching. I try to maintain good neighbors and swap labor of this sort but even six weeks is a long time and lots of things do go wrong in six months.
Without at least weekly attention? Water goes low, filters stop working, water is polluted and then it goes down fast. One silly fish in the wrong place can die and foul the whole thing. I would simply bite the bullet, save the equipment and consider it part of the cost of operations.
I would not want to come back knowing the mess I had to deal with as it is far worse than initial setting.