If you have signs of rootrot at that young age, then the first lesson you should have gained is they don't take as much water as you believe. Overwatering is probably the biggest mistake new grower make the second being trying to use too much in the way of nutes. Allow your soil to slightly dry between waterings, the roots will love you for this with more vigorous growth and develop a better root system. In time and with practice you will be able to read your leaves to determine when they need water, lol, probably a lot of disagreement but over the years I have found it is better to allow the plant to almost droop a tad before I water. I use the drench method and the soil is without doubt saturated when I am finished, this forces out all the air in the soil so that as it dries it is replaced helping the root system. Hope this helps a little anyway.