Hmm, One leaf curling down. The rest of the plant looks quite healthy, new growth, etc. How often do you water? If you water the Hesi way (a metered amount every day). You may want to reduce the amount a touch......I run Hesi in some combo grows and water a metered amount daily (that is plant/pot size dependent as to the amount watered). It took several years to zero in my amounts and you still have to play by ear as some strains use more then others. Stick your finger in the soil up to the first knuckle. Feel dry? = water. Feel damp? = don't water till dry feeling.
Here's a couple of notes on Hesi that the makers don't tell you.
In veg the Root Complex only needs to be used once a week in soil.
Power clean should be used at every 3rd - 4th watering ( I don't use it as I water with an AACT Tea, alternating one feed, one plain water, one feed, one tea, one feed, one water, one feed, one tea,,,etc,etc.). To employ this style you should drop the SuperVit and get something called SEA GREEN. This is and uptake regulator and increases the uptake of the nutrients. The Tea will increase the amounts of available nutrient to be usable by the plant. So then as Hesi says to feed at every watering has now become the wrong thing to do as the combination of the Tea and the Sea Green will make up for the what seems like under feeding.
Any way, check your soil's dryness before you water and Run the Root and Power clean that way (Hesi said this in a press release in Holland) and save money. Give my method a shot and save LOTS of money! Better yet go Organic like most of my grow and save lots more money!
good luck