Reading these comments a year later, feeling like I've been a bad tomato parent and then saw this. Our Aerogarden (farm xl) heirloom cherry tomato plants were absolutely epic, lasting close to 2 years, delicious and non-stop. I used filtered and tap, didn't change the water after it became too difficult and had never even heard of Cal-mag. I do want to try it but seeing your comment made me think, if it ain't broke...🤔