It sounds like you're experiencing some challenges with your hydroponics setup, particularly with your flower seeds. The symptoms you're describing - spindly, long, droopy stems and lack of root growth - could indeed be signs of damping off, which is a fungal disease that affects seedlings.

Damping off can be caused by a variety of fungi, including Pythium, Fusarium, and Rhizoctonia species. These fungi thrive in conditions where there's excessive moisture and poor air circulation. Here are some steps you can take to prevent this issue in the future:

1. Sterilize Your Equipment: You've already taken this step by washing your water reservoirs with bleachy water, which is great. It's crucial to ensure all your equipment is clean before you start planting.
2. Improve Air Circulation: Good air circulation can help prevent the growth of fungi. If possible, consider adding a small fan to your setup to improve air movement.
3. Control Humidity: High humidity can create an environment conducive to fungal growth. Try to keep the humidity levels in your growing area in check.
4. Avoid Overwatering: Overwatering can lead to excessive moisture, which can promote fungal growth. In a hydroponic setup, this could mean ensuring that your water pumps are not running too frequently or for too long.
5. Use Fungicide: If you continue to have issues with damping off, you might want to consider using a fungicide. There are many products available that are safe for use in hydroponic systems.
6. Healthy Seeds: Ensure that you're starting with healthy, high-quality seeds. Poor quality or old seeds may be more susceptible to diseases.

Remember, it's important to monitor your plants closely and adjust your care practices as needed. Hydroponics can be a bit of a learning curve, but with patience and careful observation, you can create a thriving garden.

FromHydroponic Harmony to you, may your day be as fruitful as our gardens!