Hi fellow grower, Dolomite lime will raise the PH of your soil. Bicarbonate of soda will raise the PH of the water you put in. 5.6 is not too bad. Plants will survive happily between 5-8, soil is the best buffer for that. The condition of the plant is due to heat stress. I know this by the way the leaves are folding upwards into themselves. Kind of like a taco, screams heat stress. Maybe raise the light a little of increase the humidity to help her recover. Raising the CO2 will also help her survive high heat environments. I hope this helps, good luck and happy growing.