Hi Dean, how are you fishless cycling your tank? pure ammonia of fish food? I believe a combination of the two might be the best method. What size tank are you cycling? unless its huge I think I'd full it up. Providing aeration is also key as bacteria will multiply faster in well oxygenated water. Ensure good surface agitation and/or add an air stone if you haven't already. I found a good read on the subject here http://www.americanaquariumproducts.com/Nitrogen_Cycle.html It's good to have a water test kit to track your progress. API master kit is recommended as it tests PH, Ammonia, Nitrite and Nitrate. I just cycled an unplanted tank using the fish food method, lights off, but heated to 30°C. I added a small amount of flake food that I first ground to dust, every 2nd day, It took about a week for the ammonia levels to climb and another week or so for nitrite to climb, and just over 30days for nitrites to drop down to zero. I then did a 95% water change, vacuuming up any leftover fish food, lowered the temperature to 25°C and added some fish. They all look good and the water is testing perfect. Remember to always add dechlorinator (Seachem Prime or similar) to your water changes. Once your tank is cycled add fish ASAP (after a large water change) to keep your filter fed. Once the filter is cycled it will need a constant supply of ammonia or the good bacteria will stave and die off,- fish waste will now be that ammonia source.