Free reef tank tool
Coral Flow Requirements Finder
Check whether your coral is likely getting too little flow, too much direct flow, or a safer indirect flow pattern.
How the Coral Flow Requirements Finder Works
This reef tank flow finder compares a selected coral profile with the flow pattern you observe at the coral. It does not pretend to measure exact water velocity. Instead, it uses practical reef signals: typical flow intensity for the coral, whether movement is indirect or direct, how the coral is behaving, and whether detritus is collecting in the spot.
If you only want requirements, choose the typical requirements mode and the tool will show a starting point for the coral. If you want to evaluate a specific location, choose current-flow mode and describe what you see. The score is weighted toward coral type, flow pattern, direct blast risk, coral behavior, and dead spot signs. Optional tank turnover is shown as a secondary hint because rated pump flow is not the same as flow at the coral.
Coral Flow by Type: Soft, LPS, and SPS
Soft coral flow
Many soft corals tolerate a range of flow, but that does not mean every soft coral wants the same spot. Mushrooms commonly prefer very low to low indirect flow and may detach if blasted. Zoanthids often do well with enough movement to keep debris from settling between polyps. Green Star Polyps can handle stronger movement, but a direct jet can still keep polyps closed.
LPS coral flow
Many fleshy LPS corals are safer in low to medium indirect flow. Torch, hammer, frogspawn, Duncan, chalice, Favia, Favites, and Goniopora should usually show gentle movement rather than tissue being pinned or whipped. If a pump stream hits one side of the coral, reducing intensity may not be enough. Diffusing the stream toward glass, surface, or rockwork is often a safer adjustment.
SPS coral flow
SPS corals usually need stronger random turbulent flow than many soft corals or LPS. Acropora commonly needs high to very high movement, while Montipora and Birdsnest often start around medium to high. The goal is broad movement from multiple directions, not a narrow pump jet pointed at tissue. Detritus collecting inside branches is a useful warning sign for too little local movement.
Direct Flow vs Random Indirect Flow
Direct flow means a narrow stream is hitting the coral. That can be risky even when the overall tank turnover number looks normal. Random indirect flow is usually safer because it moves around rockwork, changes direction, and lets polyps sway instead of being pinned. When adjusting pumps, make small changes and observe the coral over several days.
Flow checklist
What to watch before moving pumps
Coral flow decisions are usually clearer when you combine coral ID, polyp movement, and debris patterns instead of relying on a single pump rating.
Do polyps sway, barely move, or whip hard?
Is the stream direct, pulsing, or diffused by rockwork?
Does detritus collect on the coral or nearby?
Is this coral a fleshy LPS, soft coral, or SPS?
Coral flow FAQ
How much flow do soft corals need?
Many soft corals are started in low to medium indirect flow. Mushrooms often prefer very low to low flow, while Green Star Polyps can handle more movement. Use coral response and detritus buildup as feedback.
How much flow do LPS corals need?
Many LPS corals prefer low to medium indirect flow where fleshy tissue moves gently but is not pinned in one direction. Torch, hammer, frogspawn, chalice, and Goniopora can be irritated by direct pump blast.
How much flow do SPS corals need?
SPS corals usually need medium to very high random turbulent flow, depending on the coral. Acropora commonly needs stronger flow than many Montipora or Birdsnest starting points, but a narrow direct jet can still damage tissue.
How can I tell if a coral has too little flow?
Possible signs include detritus collecting on or around the coral, polyps barely moving, stagnant pockets around branches, or SPS colonies collecting debris internally. These signs should be checked alongside coral ID, light, and water conditions.
How can I tell if flow is too strong?
Possible signs include polyps being whipped hard, tissue staying retracted, fleshy LPS tissue pulled tight, mushrooms detaching, or irritation on the side facing a pump. Direct blast is often riskier than broad turbulent flow.
Is tank turnover the same as coral flow?
No. Rated pump flow and display turnover are only rough hints. Rockwork, distance, pump angle, flow mode, coral shape, and pump maintenance all change the actual movement at the coral.
What should I do if I do not know the coral ID?
Use a conservative indirect moderate-flow spot until the coral is identified. Coral Identifier can scan a photo and provide likely matches, but you should still verify with trusted reef references before major placement or pump changes.
Identify the coral before major flow changes.
Flow needs depend heavily on coral type. Use Coral Identifier for likely photo matches, then verify with trusted reef references and observe coral response.