Keep in mind that liquid carbon isn't the same thing as co2. Adding a timer and Seachem Excel are both great ideas. You have to go really crazy (way way overdose) to hurt something with excel.
The guy who said to run your lights for 4 hours, then turn them off for 3, then on again for 4 has a good point. Letting the lights 'rest' for a bit often reduces algae growth and does no harm at all to your plants. That algae is growing due to excess light and low co2. Turning off the lights for a few hours helps combat both issues. The added bonus is that you'll have more time to view your tank with the lights on when you're off work.
Simply cutting off the worst algae covered leaves is another option for crypts, swords and Anubias plants. They will re-grow newer more pristine leaves in a short time. Just take it slowly.