Lime
Lime is a source of Calcium and Magnesium. I purchased it from a nursery as granular limestone. There are other variations of lime that may not work for gardening, so make sure you get the proper one, buy it at a garden store. Around day 16 of the Great White Shark grow brown spots started to develop on the inside of some leafs, this was a calcium deficiency. I watered all plants with a small amount of lime to replenish the necessary calcium. As a precaution on day 25 I added lime again during watering.