We have clay and honestly, it seemed to work very well for pools so far.
It is true, clay becomes complete slippery sticky mush when saturated, but it seems like it's actually hard to make that happen once compacted as long as you have drainage. It doesn't perk well, so water has trouble soaking into it unless it has time. Also, it seems to compact really well and become rock hard.
So far, my opinion is it's great for pools, bad for septic tanks and sump pumps.
It is true, clay becomes complete slippery sticky mush when saturated, but it seems like it's actually hard to make that happen once compacted as long as you have drainage. It doesn't perk well, so water has trouble soaking into it unless it has time. Also, it seems to compact really well and become rock hard.
So far, my opinion is it's great for pools, bad for septic tanks and sump pumps.