Search for "Al's Gritty mix" in House plants forum. This mix enables air circulation around the roots as well as moisture. anthurium andreanum are epiphytic in nature and require good air circulation around their roots.

If your plant is growing well but the blooms are getting smaller then use a foliar fertilizer 20:20:20, they are not heavy feeders and a fortnightly fertilizer spray will be enough.

Thanks izhar
I will give it a try.