Since the water volume is small...regular small volume of water change should be able to bring down the nitrate but please spread out your water changes over 2 to 3 weeks to avoid shocking to your live stocks since pico tank is more sensitive. Once nitrate is within range.. go easy on feeding on both corals and your pair of clowns. For long term stability and maintenance, you may want to consider puting the smallest available bag of chemipure blue to maintain your water quality after that. Madpetz do carry this product -> https://madpetzonline.com/products/chemi-pure-blue Ps: Importantly....please measure nitrate level of the new water change. It must be 0 in nitrate to begin with to see the result. Good luck and enjoy the hobby. Sent from my SM-N950F using Tapatalk