Join Date: Nov 2018
Location: Oil City PA. USA
From What I can see of the plants. They are starting to yellow the tips are browned out ( fertilizer burn) and they are lacking light.
you have an enriched substrate and have put plant tabs in already and you use flourish. With the enriched substrate there is no need to use plant tabs until the substrate is about a year old. and really even then if you use flourish once a week as is recommended You still may not need the plant tabs.
Your lighting is only 4 hours a day aquatic plants (even low light plants need at least 6-8 hours of light per day. I would get a manual timer and set the times for 8 hours on every day.