Adox Rodinal working solution at 1+50 is generally used as a one-shot developer, not reused. The usual practice is to mix only what you need for that developing session, use it once, and then discard the working solution afterward.

So for 500ml at 1+50, the common approach is:

• mix it fresh
• use it for that roll/tank session
• discard it when finished

Because it’s treated as one-shot at working strength, there isn’t really a practical reuse/storage time to plan around for the diluted solution.

For disposal, follow your local regulations. In some places, used developer can go down the drain with plenty of water, while fixer often must be collected separately for proper recycling or hazardous-waste handling.