Daily Demand
Daily demand describes the quantity of a given input, whether a dosed parameter like calcium and alkalinity or a nutritional input like coral food, that a reef tank’s organisms collectively use up over a single day. Unlike a one-time test result, daily demand reflects an ongoing, ideally consistent rate of consumption that forms the basis for setting up sustainable dosing and feeding routines.
Because this figure tends to shift as a tank matures and coral biomass increases, daily demand is best understood as a moving target that benefits from periodic reassessment rather than a value set once and left unchanged indefinitely.
Why It’s Important
- Provides the practical basis for calibrating dosing pumps, calcium reactors, and feeding schedules.
- Reflects a tank’s actual, ongoing needs rather than generic starting guidelines from a product label.
- Tends to increase gradually as coral colonies mature and overall bioload grows.
- Helps prevent both under-supplementation and wasteful, unnecessary overdosing.
How It Works
Daily demand is typically calculated by measuring how much of a given parameter is consumed over a set period, then dividing that figure down to an average daily rate. For water chemistry parameters, this often means testing before and after a period without dosing, then using the difference to estimate how much needs to be replaced each day going forward.
Once daily demand is established, reef keepers can set dosing pumps, calcium reactor effluent rates, or feeding schedules to match that figure, checking back periodically to confirm the calibration still holds as the tank continues to change.
Daily Demand and Related Parameters
Daily demand is closely tied to consumption rate, the broader concept it quantifies on a daily basis, and to calcium uptake and alkalinity consumption, two of the most commonly calculated examples. It’s also connected to dosing pumps and coral feeding schedules, the practical tools used to meet that demand consistently.
Recalculating daily demand periodically, particularly after adding new coral frags or noticing shifts in growth, helps keep dosing and feeding routines aligned with a tank’s actual current needs rather than outdated figures from months or years earlier. Many reef keepers build this reassessment into a regular maintenance routine, checking key parameters on a consistent schedule specifically to catch demand changes early.
Some reef keepers find it useful to express daily demand in practical, everyday terms, such as milliliters of a specific supplement per day, rather than abstract concentration changes alone, since this makes it much easier to translate directly into a dosing pump’s programmed schedule or a manual dosing routine.
Common Misconception
A common misconception is that daily demand, once calculated, remains accurate indefinitely. In reality, it typically rises as a tank matures and coral biomass increases, meaning dosing and feeding routines set up early in a tank’s life often need periodic recalibration to stay properly matched.
The Bottom Line
Daily demand quantifies how much of a given input a reef tank actually uses over a 24-hour period, forming the practical basis for dosing and feeding routines. Reassessing it periodically helps ensure those routines stay matched to a tank’s real, evolving needs.
