You can talk all you want about the pH of what goes into the tank or not, but a simple pH test of yours versus others will make that determination.
Trust me, I've seen a LOT of hugely bad concrete in my time; on roads, on sidewalks, in foundations, on patio slabs, on any kind of casting you can think of. Bridges have fallen down because of bad concrete. Why does anyone think that someone making cast concrete septic tanks would be immune to such things? The funny thing is, in exterior concrete work you know quickly how bad the concrete is, but rarely is any concrete supplier or finisher held responsible. but I digress.
In my last home, we were on a clean crawl space foundation, cement floor, 1,000 gallon septic tank, condensing furnace and a/c unit in the crawl space. Soil condition in the area was mostly sandy, excellent drainage. The condensate did NOT go into the septic; what they did at the time of build (1996) was bury a five gallon bucket at the foundation edge, where the DWV line exited the house into the septic. This was INSIDE the crawl space, and cemented in place when they added the concrete floor to the crawl space. They added some cracks/holes to the bottom of the bucket, and the condensate drained into there and eventually into the sandy soil below. While it was generally wet inside the bucket, it never "held" water.
I don't know if this was done by code, for code, or to avoid a condensate pump which would require pumping UP about 24" or so. This setup drained all by gravity.
