The simple system above will allow for the plants to be watered every 2-3 days. However, hot days or larger plants will require daily watering. If your plant is wilting in the sun, you may need to move it out of direct sunlight during the hotter parts of the day. Under hot conditions, using a shade cloth may be more appropriate.
When watering, different plants absorb different nutrients at different rates. For example, a lettuce plant will only need half the concentration of a tomato plant otherwise the leaves may taste bitter. Simply dilute the SurviveN General Purpose Hydroponic solution that you give to your tomatoes, zucchinis, capsicums and eggplants by half when you water your lettuces, herbs, all young seedlings and other leafy plants. To avoid any build-up of excess nutrient salts flush all your plants with fresh water once a month.
Unless you collect rainwater in a tank, town tap water is not suitable when watering your plants right away. It contains chemicals, such as chlorine, that can greatly affect your plant's growth or even kill them. Let the tap water sit for 24hours in a container to allow the chlorine to evaporate out.
Rain is generally not a problem unless it is for more than 2 days. The nutrients are salts and saltwater is heavier than water. The nutrient solution will remain at the bottom of the container while most of the fresh rain water will drain out. The tomato fruit has a tendency to split if it is exposed to too much fresh water. If this hydroponic setup is placed in a greenhouse then you will have greater control over the environmental conditions that can affect your plant's growth.
Any excess nutrients that flow from the drainage hole can be recycled.