Summary: Every fish in your seafood tank produces ammonia with every breath. A 500-liter tank with 50 lobsters generates about 1.2 grams of ammonia per day. Your sump has to process all of it. After designing 40+ seafood filtration systems, I can tell you: most sumps are undersized by 40-60%. The filter media volume is too small. The bacteria colony can't keep up. That's why ammonia spikes. That's why lobsters die.
Every lobster in your tank breathes.
Every breath produces ammonia.
That's not a metaphor. That's biochemistry. Fish excrete ammonia through their gills. It's the waste product of protein metabolism.
A 500-liter tank with 50 lobsters? That's about 1.2 grams of ammonia per day.
Your sump has to process all of it. Every gram. Every day.
Let me show you how that works.
The Ammonia Load Calculation
Here's the math.
A lobster produces about 24 mg of ammonia per day.
50 lobsters × 24 mg = 1,200 mg = 1.2 grams per day.
That's the ammonia load.
Your sump has to convert all of that ammonia into nitrate. Through the nitrogen cycle.
The Bacteria Colony
Here's what most people don't understand.
The sump doesn't "filter" ammonia. Bacteria eat it.
Nitrosomonas bacteria convert ammonia into nitrite. Nitrobacter bacteria convert nitrite into nitrate.
That's the cycle.
The question is: do you have enough bacteria?
The Filter Media Volume
Here's where most sumps fail.
The rule of thumb: you need about 1 liter of filter media per 100 liters of tank water.
For a 500-liter tank? That's 5 liters of media.
Most cheap sumps have 2-3 liters. That's 40-60% undersized.
Not enough media = not enough bacteria = ammonia spikes.
The Media Type
Not all media is equal.
Cheap bio balls: 100 m² of surface area per liter. Ceramic rings: 500 m² per liter. Moving bed media (K1): 900 m² per liter.
That's 9x more surface area with the same volume.
More surface area = more bacteria = more ammonia processed.
The Flow Rate
Here's the third variable.
The water has to flow through the media. But not too fast.
If the flow is too fast? The bacteria don't have time to process the ammonia. The water just passes through.
The rule: 4-6x turnover per hour.
For a 500-liter tank? That's 2,000-3,000 GPH.
The 40-System Lesson
I've designed 40+ seafood filtration systems.
The systems that fail? They have undersized sumps. Cheap media. Wrong flow rate.
The systems that work? They have proper media volume. Good media type. Correct flow rate.
That's the difference.
What I'm Not Going to Tell You
I can tell you how much ammonia your tank produces. I can tell you how big the sump needs to be. I can tell you what media to use.
But I'm not going to tell you which seafood to buy. I'm not going to tell you how to price the menu. I'm not going to tell you how to run the restaurant.
That's not my department. I design the filtration. You run the business.
What We Design at Ruibit
At Ruibit, we don't sell the cheapest sump.
We design the sump that handles the ammonia load.
Every system we design has:
- Proper media volume (1L per 100L)
- High-surface-area media (ceramic rings or K1)
- Correct flow rate (4-6x turnover)
We tell every customer: "Every breath is a deposit. Your sump has to process all of it."
That's what we've learned from 40+ filtration designs. The customers who get a properly sized sump? They never have ammonia spikes. The customers who get a cheap undersized sump? They call us when the lobsters start dying.
The 1.2 Grams
1.2 grams of ammonia per day.
That's what 50 lobsters produce.
Your sump has to process every gram.
Every breath is a deposit. Make sure your bank can handle it.
