Built a simple free tool for aquarium hobbyists — looking for honest feedback

Hey everyone, I built this free service to help fish keeping hobbyists view and maintain their tank, while also linking it to another business idea.  

It takes about 30 seconds to try: 
https://aqua-reels.replit.app/tank 

I’m not selling anything — just trying to figure out: 

• Is this actually useful? 
• What feels confusing? 
• What would make you use this regularly? 

Brutal honesty welcome. I’d rather fix it now than build the wrong thing.