May I ask why you say that. I have the opposite view kinda... while some tap is not suitable most is imo.Tap water is a big no no. It has minerals that you can’t account for not mention chlorine which is toxic to plants. Always use RO water. Ocean Forrest is fortified to supply your plant with everything it needs for the first 20 30 days so don’t add any nutes unless its kelp or something with little to no Macros or NPK levels. Kelp is mainly micro nutrients. I suggest you study the basics use high quality water and do not over water. The best way to get a idea on how often to water is by feel. Pick up your pot after you water then pick it up every day and you’ll feel it become significantly lighter. Generally soil can go at least a few days but if you have a 15 gallon pot and water heavily one could go 5 days or longer. Signs of overwatering are exactly as your plants look droopy slow to no growth possible necrosis and browning. Another thing to consider is light intensity. Your plants are young so ease into.