The cycled sponge filter and a little bag of cycled bio rings are tucked in the back. I had the filter items in a grow out tank that previously held my EBA fry until I moved them to large tank. I'm checking water daily since newer setup in 10 gal quarantine tank I watched it for about a week and all good. Two days almost new fish and water was perfect. PH 6.8-7 0 on all others. Also, the water in this area has low PH and low KH GH. I've raise it a little with crushed coral