To keep stem plants in the substrate you can wrap two or three stems in a lead weight and plant weight an all. They should root on their own. You can also weight them in large bunches. For Crypts, Echinodorus, rooted plants you can use the weights at their base and remove once established.
I did the latter with an Anubias by wrapping the rhizome. When I pulled it up to replant
the roots covered the entire bottom of 2.5 gallon!
Thankyou. They are weighted except for the bamboo. I think I need to get an overhead light for when I want to do something in the tank because I can barely see when the top's off. Leave it off most of the time and just use it when doing tank stuff. Love the apartment but biggest drawback is no overhead lights or fans