Everyone's tap water is different, but switching to pure water would typically involve mixing a lower PPM nutrient solution. You may have been starting with 300 ppm tap water, but that would have been mostly calcium and largely irrelevant to the plant's needs. If you switch to distilled and mix nutes to the same PPM, then that 300 or so that used to be irrelevant calcium is now NPK. The plant experiences a much higher nutrient concentration, even though your PPM reading is the same.

A ppm of 900+ might be a bit much for the plants. I only run about 700 or so for tomatoes which are notoriously heavy feeders.
Or, As I believe Cole was saying, they might be going through a bit of shock at the new nutrient supply.

That's Calcium deficiency. Use Ca(NO3)2 to reach a final concentration of 180 - 200 ppm of calcium.
Nitrogen concentration of 150 ppm is fine for this plant.
The pH should be between 6 - 7. The more acidic, Calcium is less available.

I concur. You may be burning the plants with such high ppm since the majority of the TDS levels are from NPK. You also will need to add calcium since you took out the main source of calcium, tap water.

My suggestion is to half the nutrient strength, and purchase some CalMag supplement and use that to make up for the lack-there-of. If the plants bounce back then you can try to raise the nutrient strength slowly and see how the plants react.

Wrinkly leaves usually = Ca deficiency or bugs

Burned tips usually = nute burn or light burn

This post was edited by ethnobotany on Sat, Jan 12, 13 at 19:57