My best guess regarding the logging is your router does not have crontab installed which is what runs the ‘watcher.php’ script every minute and saves the results to the $log_file and $log_previous files. I think tomato firmware might have an option to turn on crontab. If it does all you need to do is add the watcher.php to it.
To install crontab you should be able to just use:
ipkg-opt install cron
The crontab line for your router should be something like:
* * * * * cd /opt/share/www/sprinklers; /opt/bin/php-fcgi /opt/share/www/sprinklers/watcher.php
In your config.php check that your $log_file and $log_previous files exist and are writable by PHP.
In regard to the tip header, I have updated the CSS to fix the header in IE10 and Firefox but in the long term I do not think I want to spend much time supporting IE or Firefox since both browsers are primarily desktop and the normal interface is sufficient, IMO.