good answer.
another way to look at it is that there is probably very little alkalinity since it is tap water. In the pool business we just call it "ph bounce".With some hardness in the water it won't bounce so much.=BUFFERS = TDS.
the one thing I love about this is that there are almost an unlimited # of ways to do everything. here is one very simple and efficient way to clone.
Setup: Bathtub , pvc frame to support lights and clear plastic sheet,aquarium heater>20 gal.KEEP WATER TEMP 78-80 DEGREES.4' shop light
1/2" pvc...