Drainage

When was the last time you watered? The soil could be water repellant because it hasnt been watered for a long time?

i know you are just playing around, but... I promise i don't think of them as 'my' ideas.. these are well-known, established behaviors that apply to most potted plants... some stuff is picky out there, but marijuana is not. There's been some really bad advice on watering the last few months... so it's good that more people explain it the right way, otherwise urban myths form.

Yes, ideal to get some run-off.............it is the only way to know water has reached the bottom of the pot where the roots are too. Never water a fixed amount every X days or to a preconcieved schedule. Each plant will need its own amount and own frequency. Simply put............water enough to get some run off, then do not water again until the top inch or so is dried out.............be that half a day or 5-7 days. Otherwise, our resident watering guru, 0011, has given solid advice again.

Depends on how much 500mL is compared to how much is needed for that size of a pot and the constitution of your medium. Take a different approach. You give whatever is necessary to complete the task. Some runoff is inevitable, but you can minimize it with greater familiarity / experience. If it is a soilless context, you also want a minimum of 10% runoff. That is how you avoid buildup around the roots. The runoff is absolutely integral to that method of growing. Never let any potted plant sit in its piss. Short-term isn't a big risk, but it's a bad practice that will eventually lead to a problem you should have 100% avoided. It'll be a consistent volume if you wait for the same dryback each time. You can learn it in hindsight. Same depth of dryness or loss of weight are 2 good observable 'triggers' for an irrigation. Don't choose the volume. Don't choose the frequency. You simply react and complete the task. So, unless a large portion of that 500mL came out the bottom, it's probably fine... even a good thing that 'some' runoff occured. Just don't jump the gun trying to reirrigate too soon. Allow the top inch or so to dry (if soil) and feel the weight of the pot to get familiar... Soon all you'll do is give a gentle tug on a pot and know when to water and with roughly how much. in coco coir, as that top layer starts to change colors, that's probably an equivalent to waiting for 1" deep to dry in a soil.