DO NOT turn your filters off under any circumstances. You need to go to the tank setup section and read the information on filters very carefully. Filters are not just for removing solid waste, they also remove toxins from your water. To do this, you need beneficial bacteria which lives in the media inside your filters. These type of bacteria rely on oxygen to survive. The oxygen is created by the water running through the filtration system. Once you turn your filters off no oxygen is produced and your bacteria all die.
It is extremely common for the Oscars to eat the eggs. The filtration won't suck the eggs up because they are covered in a substance that sticks them to the surface where they are laid. Remember that you may not have a male and female. Two females will still lay eggs and give you the impression that they are looking after them ready for them to hatch. If they are not fertilise, they will eat the eggs. I have got two green severums, both female. They lay eggs on a regular basis and look after them exactly the same as the male and female wood. Obviously the eggs never hatch. Oscars will do exactly the same. If you've got other fish that they may disturb the Oscars which is why they often eat the eggs.
Next time you see them laying eggs have a look underneath where their sexual organs. The females is quite obvious, it's oval and white and often sticks out quite a bit. The males is like a little spike and isn't so obvious. If the female is laying eggs and you can't see anything on the other fish then the chances are you haven't got a breeding pair. Even if you have got a male and female, they may not fertilise the eggs properly.
Just let me reiterate what I said before about your filtration system. If you leave your filtration for more than two or three hours, the majority of your bacteria will die and dangerous toxins will start building up in your water which won't do your fish any good. You will then have to cycle your tank over again.
