I believe the Dumaguete Water Department will pump out septic tank sludge. Free every three years if i remember correctly, maybe P1600 if less than 3. Might be part of the problem.
If it is just ground water why in the world would you need a GRINDER PUMP? You need to find out how and where the water is getting in and stop it. Your leach field may be the problem.
We found out the hard way that the septic tanks there do not have lateral lines as we are used to here (0r ours didn't, anyway), so they fill up much quicker. Luckily, it isn't very expensive there to have it pumped out.
Most septic tanks in this country do not have a leach field, most are built with no bottom, only dirt and not concrete. My septic tanks always get filled up after real heavy rains if there is standing water in the yard or in the area where the septic tank is located.
