It's hard to say without more information:
1) how much do you feed at the most in one sitting
2) what do you feed in protein content
3) what is your pH and temp
4) how good is the circulation in your tank
5) how much water is in your system
6) how much protein in the food is converted to tissue
7) the hourly rate of protein to ammonia conversion
8) turnover rate on the sponge filter
Given what you said however, I took a whack at this.
Assumptions:
1) You have 3.35 lbs of fish (based on length and girth)
2) your max feeding is 4% of body weight
3) food is 90% dry weight and 50% protein (carnivore pellet configuration)
4) you have 80 gallons of water in your system
5) temps are 82 F
6) 6% of the nitrogen is used for tissue growth (this is from a study on fish that were between fry and 150 grams in size)
7) ammonia after feeding is created per hour at 8%-22%-14%-9%-7%-6% etc. (per a study I found on the matter regarding trout)
This provides for a total of 11.4 ppm of ammonia, but a peak of 2.5 ppm during hour 2, assuming bacteria can reduce at least 1.5 ppm per hour. (If not, the ppm will continue to grow until the conversion rate is matched.)
Let's assume you want to keep ammonia levels to .25 ppm or below and that the filters are converting 100% of ammonia on the first pass. You'll need a 10x per hour (every 6 mins) turnover at a minimum, assuming the peak rate of 2.5 ppm occurs evenly throughout hour 2.
In reality, you won't get 100% conversion and not all water in the tank will turnover equally fast, so you'll want more turnover. The AC70 and AC110 are rated around 900 gph and the sponge filter is unknown, but ratings are rarely close to actual gph, especially as the filter material becomes less clean. This is barely the needed amount with little surplus. Nitrates will still accumulate even if nitrite and ammonia are under check.
Reducing feeding at any one meal to not more than 2% of fish weight (feeding twice a day, smaller portions) will help a lot.
Reducing protein content of foods will reduce nitrogen conversion demands.
Having a larger amount of water in the system will help a lot as well as it dilutes the nitrogen (ammonia, nitrites, nitrates) in the tank
Large WC and / or addition of plants (e.g., pothos) can effectively reduce nitrates.
This assumes no growth in the fish, which obviously is not practical.
