THE GEAR REAL REEF TANKS RUN ON | TOURS · EQUIPMENT · GUIDES

ALLCORALS REEF TANKS & GEAR
The New Reefer's Path

Reefkeeping, in the order it actually happens.

From an empty box to a stable reef — every stage has one thing to master and a hard gate before you move on. Follow the path, browse by topic, or just ask the reef your worry in plain words.

Stage 1 of 7

Planning your first reef

Decide tank size, budget, and what kind of reef you want before you buy anything.

Coming soon. Decide tank size, budget, and what kind of reef you want before you buy anything.
Stage 2 of 7

Setup — building the box

Install and stabilize the physical system: salt water at 1.025, heater, flow, rock, sand.

Gate to advance
Salinity holds ~1.025 sg and temperature holds 76-78F for a few days with everything running.
The bacteria you are about to grow need a stable environment; a swinging box never cycles cleanly.
?Why can't I use tap water for my reef tank?Tap water carries chlorine/chloramine, dissolved metals, and variable nitrate/phosphate/silicate that a reef tank can't tolerate — the silicate alone is enough to feed a worse-than-normal diatom bloom. RO/DI (reverse osmosis + deionization) strips water down to a target of 0 ppm TDS (total…beginner4 minWater chemistryEquipment→?How do I mix saltwater to the right salinity?Dissolve a reef salt mix into RO/DI water until it reads 1.025 sg (35 ppt) on a refractometer, then let it circulate with a pump or powerhead for a few hours (many reefers go overnight) so it fully dissolves and the temperature settles — don't pour freshly-mixed water straight into the display.beginner4 minWater chemistryEquipment→?What equipment do I actually need to start a reef tank?Day-one essentials are a tank, heater, light, a way to make saltwater (RO/DI + salt mix), a refractometer, a test kit, a thermometer, a net, and at least one powerhead for flow. A protein skimmer, dosing pumps, a controller, and a refugium are all real upgrades — but they can wait; buying them…beginner5 minEquipment→?What temperature should my reef tank be, and how do I pick a heater?Hold your tank at 76-78°F, day and night, with a heater sized to your tank volume and checked against a separate thermometer (never trust the heater's own dial alone). Because a heater failing "stuck on" is repeatedly named the #1 cause of beginner tank crashes, run two smaller heaters instead…beginner4 minEquipmentWater chemistry→?How much flow does a reef tank need?Aim for roughly 7-10x your total tank volume per hour of turnover from your return/circulation pump, delivered as random, variable flow from more than one point rather than a single strong jet — the goal is no stagnant "dead spots" where detritus and cyanobacteria build up, not hitting an exact…beginner4 minFlowEquipment→?Should I use live rock or dry rock?Dry (base) rock is the recommended default — cheap, pest-free, and you cycle it from scratch with dosed ammonia. Live rock brings existing bacteria, coralline algae, and biodiversity that can speed things up, but it also risks hitchhiker pests (aiptasia, bristle worms, mantis shrimp) and is…beginner4 minEquipmentBiology→?What sand should I use, and how much?Place rock directly on the glass bottom before adding sand, then add a shallow bed (1-2 inches) of reef-grade sand — fine "sugar" sand is easiest for most tanks, while a coarser Special Grade (~1-2mm) holds up better under strong flow. Size the quantity with a sand-bed calculator for your tank's…beginner4 minEquipmentBiology→?How do I aquascape my reef tank?Plan your scape outside the tank first, use less rock rather than more (better flow, more open swimming space), follow the Rule of Thirds for visual balance, and build in flow paths and negative space rather than a single solid wall of rock — then secure anything top-heavy so it can't topple…beginner4 minEquipment→?What setup mistakes should I avoid before cycling?The setup stage isn't done until salinity holds ~1.025 sg and temperature holds 76-78°F for a few days with everything running — heater, flow, light, all of it. The single biggest mistake is treating "the tank is full and looks fine" as that signal; run a full leak test first, verify with a…beginner4 minEquipmentWater chemistryTroubleshooting→
Stage 3 of 7

Cycling — growing your biological filter

Grow the invisible bacteria that convert toxic fish waste into something livestock can survive.

Gate to advance
Both ammonia AND nitrite read 0 ppm 24 hours after you dose the tank to about 2 ppm ammonia.
Until the bacteria can clear a full ammonia dose overnight, any livestock is poisoned by its own waste.
?What is the nitrogen cycle, and why does my tank need to cycle?"Cycling" means growing a colony of invisible bacteria that convert the toxic waste your animals produce (ammonia) into nitrite, and then into far-less-toxic nitrate. Until that bacteria colony exists, anything you put in the tank is poisoned by its own waste. Cycling takes anywhere from a few…beginner4 minWater chemistryBiology→?Why can't I add fish to my new tank right away?In a new tank the ammonia-eating bacteria don't exist yet, so a fish added on day one is swimming in its own toxic waste with nothing to remove it. Ammonia and nitrite burn their gills and can kill them within days. Wait until the tank is cycled — ammonia and nitrite both reading 0 — which is…beginner3 minBiologyLivestock→?What's the best way to cycle a saltwater tank?The two methods worth your time are fishless cycling with dosed ammonia (precise, humane, reliable) and the same thing sped up with bottled bacteria (as fast as 5–14 days). Live rock also works and adds biodiversity but risks pests. Never cycle with a fish, and never use household ammonia.beginner5 minWater chemistryBiologyEquipment→?How do I cycle my tank with pure ammonia (fishless cycling)?Set the tank up fully, dose aquarium-grade ammonium chloride to about 2–4 ppm, and test every 2–3 days. When nitrite appears, keep ammonia near 2 ppm. You're done when a fresh ~2 ppm dose is processed to 0 ammonia and 0 nitrite within 24 hours. On dosed ammonia alone this takes about 3–6 weeks;…beginner5 minWater chemistryBiology→?How do I cycle my tank fast with bottled bacteria?Add a bottle of live nitrifying bacteria (Dr. Tim's One & Only or Fritz TurboStart 900) and an ammonia source at the same time, turn off your skimmer and UV, and test daily. This seeds the colony instead of waiting weeks for it to appear — most tanks finish in about 5–14 days. Product freshness…beginner5 minWater chemistryBiologyEquipment→?How long does it take to cycle a saltwater tank?With bottled bacteria plus dosed ammonia, most tanks cycle in about 5–14 days. On dosed ammonia alone it's 3–6 weeks, and uncured live rock can take 4–8 weeks. But the calendar doesn't decide when you're done — the test does. You're finished only when a ~2 ppm ammonia dose is cleared to 0…beginner3 minWater chemistryBiology→?What should my water parameters look like at each stage of cycling?Cycling moves through four readable phases. First ammonia rises, then it falls as nitrite spikes, then nitrite falls as nitrate rises, and finally both ammonia and nitrite hold at zero while nitrate accumulates. The high nitrite spike in the middle is normal and the most nerve-wracking part —…beginner4 minWater chemistry→?How do I know when my tank is done cycling?Dose the tank to about 2 ppm ammonia, wait 24 hours, and test again. If both ammonia and nitrite read essentially 0 (below 0.2 ppm) the next day, the cycle is complete — your bacteria can clear a full day's waste overnight. If either is still detectable, you're not done; keep going and retest.…beginner3 minWater chemistryBiology→?My new tank is covered in brown/green/red algae — is something wrong?Almost certainly nothing is wrong. Every new reef tank goes through the "ugly phase" — a normal, expected 3–6 months of brown, green, and sometimes red blooms as the system matures and finds balance. It looks like failure and it isn't. The worst thing you can do is panic and start ripping the…beginner5 minTroubleshootingBiologyMaintenance→?What are the most common cycling mistakes to avoid?The big ones are impatience (adding livestock before the tank can support it), over-cleaning (scrubbing away the bacteria you're growing), and interfering chemically (ammonia-removers, medications, or a running skimmer that starve or strip the bacteria). Let the cycle run, test, and don't fix…beginner4 minWater chemistryBiologyTroubleshooting→?My tank is cycled — now what do I do first?Before any animals go in, do a large (50–75%) water change to drop the nitrate that built up during cycling, then confirm your parameters are stable for about a week. Add life slowly and in order: clean-up crew first, then a hardy fish or two, then corals over the following months. Never dump in…beginner4 minLivestockMaintenanceWater chemistry→
Stage 4 of 7

First livestock — clean-up crew and first fish

Add life slowly and safely: acclimate, quarantine, and let bacteria catch up between additions.

Gate to advance
Cycle is confirmed complete, parameters have been stable for a week, and nitrate is under 20 ppm after a water change.
A confirmed, rested, low-nutrient system survives its first animals; a freshly-finished cycle with high nitrate does not.
?What clean-up crew should I add first, and why?Snails, hermit crabs, and other grazing invertebrates go in first because they're hardy, add almost no bioload, and eat the diatom/algae blooms of the "ugly phase" that hits right as your tank matures. Add a small starting group, then let algae growth tell you if you need more — don't dump in a…beginner4 minLivestockBiology→?How do I tell if a fish at the store is healthy before I buy it?Watch the fish for a few minutes before you buy it — a healthy fish swims normally, breathes evenly, has intact fins and clear eyes, and eats readily when the store feeds it. Any white spots, rapid breathing, scratching against rock, clamped or tattered fins, or a refusal to eat means walk away,…beginner5 minLivestockTroubleshooting→?How do I acclimate a new fish or invertebrate to my tank?Float the sealed bag in your tank until temperatures match, then slowly mix tank water into the bag or a container over time (drip acclimation) instead of dumping the animal straight in. This gives it time to adjust to your tank's salinity, pH, and temperature without shock. Invertebrates are…beginner4 minLivestockWater chemistry→?Why do I need a quarantine tank, and how do I set one up?A quarantine tank (QT) is a separate, bare-bones tank where every new fish lives alone for 3–4 weeks before it ever touches your display — long enough to see and treat diseases like ich or velvet before they reach a tank you can't safely medicate. Skipping QT is the single most common way a new…beginner5 minLivestockTroubleshooting→?What fish should I add first to a new reef tank?Start with hardy, peaceful, easy-to-feed species — ocellaris clownfish, chromis, and cardinalfish are the classic first fish. Add peaceful species before aggressive ones, and skip anything that needs a huge tank, specialized live food, or months of established rock (tangs in small tanks,…beginner5 minLivestock→?How many fish can I add at once, and how fast?Add no more than 2–3 fish at a time, then wait 1–2 weeks before the next addition. Your bacterial colony is only sized to handle the waste load it's currently processing — each new fish is a small bioload spike, and the bacteria need time to grow to match it.beginner3 minLivestockBiologyWater chemistry→?What are the most common first-livestock mistakes to avoid?Nearly every early livestock death traces back to one of a handful of repeat mistakes — no quarantine, skipping drip acclimation, adding too much too fast, buying a visibly stressed or sick fish, or medicating the display tank instead of a separate QT. Slow down and this stage is very forgiving.beginner4 minLivestockTroubleshooting→
Stage 5 of 7

Stocking — building the community

Add fish 2-3 at a time with waiting periods, watching bioload and compatibility.

Gate to advance
Nitrate and phosphate stay controlled as you add fish, and the community is peaceful.
The bacterial colony grows to match the bioload; each addition needs time for it to catch up.
Coming soon. Add fish 2-3 at a time with waiting periods, watching bioload and compatibility.
Stage 6 of 7

Maturity — first corals and stability

Hold parameters steady long enough that soft and LPS corals thrive; consistency beats perfection.

Gate to advance
Alkalinity, calcium, and magnesium hold steady for weeks, and soft/LPS corals are open and growing.
SPS and demanding corals need proven stability over months, not a single good test.
Coming soon. Hold parameters steady long enough that soft and LPS corals thrive; consistency beats perfection.
Stage 7 of 7

Advanced — dosing, SPS, automation

Automate stability (dosing, controllers, ULNS) so the tank can carry demanding SPS.

Coming soon. Automate stability (dosing, controllers, ULNS) so the tank can carry demanding SPS.
Browse by topic
?What's the best way to cycle a saltwater tank?The two methods worth your time are fishless cycling with dosed ammonia (precise, humane, reliable) and the same thing sped up with bottled bacteria (as fast as 5–14 days). Live rock also works and adds biodiversity but risks pests. Never cycle with a fish, and never use household ammonia.beginner5 minWater chemistryBiologyEquipment→?What are the most common cycling mistakes to avoid?The big ones are impatience (adding livestock before the tank can support it), over-cleaning (scrubbing away the bacteria you're growing), and interfering chemically (ammonia-removers, medications, or a running skimmer that starve or strip the bacteria). Let the cycle run, test, and don't fix…beginner4 minWater chemistryBiologyTroubleshooting→?What should my water parameters look like at each stage of cycling?Cycling moves through four readable phases. First ammonia rises, then it falls as nitrite spikes, then nitrite falls as nitrate rises, and finally both ammonia and nitrite hold at zero while nitrate accumulates. The high nitrite spike in the middle is normal and the most nerve-wracking part —…beginner4 minWater chemistry→?My tank is cycled — now what do I do first?Before any animals go in, do a large (50–75%) water change to drop the nitrate that built up during cycling, then confirm your parameters are stable for about a week. Add life slowly and in order: clean-up crew first, then a hardy fish or two, then corals over the following months. Never dump in…beginner4 minLivestockMaintenanceWater chemistry→?How do I cycle my tank with pure ammonia (fishless cycling)?Set the tank up fully, dose aquarium-grade ammonium chloride to about 2–4 ppm, and test every 2–3 days. When nitrite appears, keep ammonia near 2 ppm. You're done when a fresh ~2 ppm dose is processed to 0 ammonia and 0 nitrite within 24 hours. On dosed ammonia alone this takes about 3–6 weeks;…beginner5 minWater chemistryBiology→?How do I cycle my tank fast with bottled bacteria?Add a bottle of live nitrifying bacteria (Dr. Tim's One & Only or Fritz TurboStart 900) and an ammonia source at the same time, turn off your skimmer and UV, and test daily. This seeds the colony instead of waiting weeks for it to appear — most tanks finish in about 5–14 days. Product freshness…beginner5 minWater chemistryBiologyEquipment→?How long does it take to cycle a saltwater tank?With bottled bacteria plus dosed ammonia, most tanks cycle in about 5–14 days. On dosed ammonia alone it's 3–6 weeks, and uncured live rock can take 4–8 weeks. But the calendar doesn't decide when you're done — the test does. You're finished only when a ~2 ppm ammonia dose is cleared to 0…beginner3 minWater chemistryBiology→?How do I know when my tank is done cycling?Dose the tank to about 2 ppm ammonia, wait 24 hours, and test again. If both ammonia and nitrite read essentially 0 (below 0.2 ppm) the next day, the cycle is complete — your bacteria can clear a full day's waste overnight. If either is still detectable, you're not done; keep going and retest.…beginner3 minWater chemistryBiology→?What is the nitrogen cycle, and why does my tank need to cycle?"Cycling" means growing a colony of invisible bacteria that convert the toxic waste your animals produce (ammonia) into nitrite, and then into far-less-toxic nitrate. Until that bacteria colony exists, anything you put in the tank is poisoned by its own waste. Cycling takes anywhere from a few…beginner4 minWater chemistryBiology→?My new tank is covered in brown/green/red algae — is something wrong?Almost certainly nothing is wrong. Every new reef tank goes through the "ugly phase" — a normal, expected 3–6 months of brown, green, and sometimes red blooms as the system matures and finds balance. It looks like failure and it isn't. The worst thing you can do is panic and start ripping the…beginner5 minTroubleshootingBiologyMaintenance→?Why can't I add fish to my new tank right away?In a new tank the ammonia-eating bacteria don't exist yet, so a fish added on day one is swimming in its own toxic waste with nothing to remove it. Ammonia and nitrite burn their gills and can kill them within days. Wait until the tank is cycled — ammonia and nitrite both reading 0 — which is…beginner3 minBiologyLivestock→?What fish should I add first to a new reef tank?Start with hardy, peaceful, easy-to-feed species — ocellaris clownfish, chromis, and cardinalfish are the classic first fish. Add peaceful species before aggressive ones, and skip anything that needs a huge tank, specialized live food, or months of established rock (tangs in small tanks,…beginner5 minLivestock→?What clean-up crew should I add first, and why?Snails, hermit crabs, and other grazing invertebrates go in first because they're hardy, add almost no bioload, and eat the diatom/algae blooms of the "ugly phase" that hits right as your tank matures. Add a small starting group, then let algae growth tell you if you need more — don't dump in a…beginner4 minLivestockBiology→?What are the most common first-livestock mistakes to avoid?Nearly every early livestock death traces back to one of a handful of repeat mistakes — no quarantine, skipping drip acclimation, adding too much too fast, buying a visibly stressed or sick fish, or medicating the display tank instead of a separate QT. Slow down and this stage is very forgiving.beginner4 minLivestockTroubleshooting→?How many fish can I add at once, and how fast?Add no more than 2–3 fish at a time, then wait 1–2 weeks before the next addition. Your bacterial colony is only sized to handle the waste load it's currently processing — each new fish is a small bioload spike, and the bacteria need time to grow to match it.beginner3 minLivestockBiologyWater chemistry→?How do I tell if a fish at the store is healthy before I buy it?Watch the fish for a few minutes before you buy it — a healthy fish swims normally, breathes evenly, has intact fins and clear eyes, and eats readily when the store feeds it. Any white spots, rapid breathing, scratching against rock, clamped or tattered fins, or a refusal to eat means walk away,…beginner5 minLivestockTroubleshooting→?How do I acclimate a new fish or invertebrate to my tank?Float the sealed bag in your tank until temperatures match, then slowly mix tank water into the bag or a container over time (drip acclimation) instead of dumping the animal straight in. This gives it time to adjust to your tank's salinity, pH, and temperature without shock. Invertebrates are…beginner4 minLivestockWater chemistry→?Why do I need a quarantine tank, and how do I set one up?A quarantine tank (QT) is a separate, bare-bones tank where every new fish lives alone for 3–4 weeks before it ever touches your display — long enough to see and treat diseases like ich or velvet before they reach a tank you can't safely medicate. Skipping QT is the single most common way a new…beginner5 minLivestockTroubleshooting→?How much flow does a reef tank need?Aim for roughly 7-10x your total tank volume per hour of turnover from your return/circulation pump, delivered as random, variable flow from more than one point rather than a single strong jet — the goal is no stagnant "dead spots" where detritus and cyanobacteria build up, not hitting an exact…beginner4 minFlowEquipment→?How do I aquascape my reef tank?Plan your scape outside the tank first, use less rock rather than more (better flow, more open swimming space), follow the Rule of Thirds for visual balance, and build in flow paths and negative space rather than a single solid wall of rock — then secure anything top-heavy so it can't topple…beginner4 minEquipment→?How do I mix saltwater to the right salinity?Dissolve a reef salt mix into RO/DI water until it reads 1.025 sg (35 ppt) on a refractometer, then let it circulate with a pump or powerhead for a few hours (many reefers go overnight) so it fully dissolves and the temperature settles — don't pour freshly-mixed water straight into the display.beginner4 minWater chemistryEquipment→?Should I use live rock or dry rock?Dry (base) rock is the recommended default — cheap, pest-free, and you cycle it from scratch with dosed ammonia. Live rock brings existing bacteria, coralline algae, and biodiversity that can speed things up, but it also risks hitchhiker pests (aiptasia, bristle worms, mantis shrimp) and is…beginner4 minEquipmentBiology→?Why can't I use tap water for my reef tank?Tap water carries chlorine/chloramine, dissolved metals, and variable nitrate/phosphate/silicate that a reef tank can't tolerate — the silicate alone is enough to feed a worse-than-normal diatom bloom. RO/DI (reverse osmosis + deionization) strips water down to a target of 0 ppm TDS (total…beginner4 minWater chemistryEquipment→?What sand should I use, and how much?Place rock directly on the glass bottom before adding sand, then add a shallow bed (1-2 inches) of reef-grade sand — fine "sugar" sand is easiest for most tanks, while a coarser Special Grade (~1-2mm) holds up better under strong flow. Size the quantity with a sand-bed calculator for your tank's…beginner4 minEquipmentBiology→?What setup mistakes should I avoid before cycling?The setup stage isn't done until salinity holds ~1.025 sg and temperature holds 76-78°F for a few days with everything running — heater, flow, light, all of it. The single biggest mistake is treating "the tank is full and looks fine" as that signal; run a full leak test first, verify with a…beginner4 minEquipmentWater chemistryTroubleshooting→?What temperature should my reef tank be, and how do I pick a heater?Hold your tank at 76-78°F, day and night, with a heater sized to your tank volume and checked against a separate thermometer (never trust the heater's own dial alone). Because a heater failing "stuck on" is repeatedly named the #1 cause of beginner tank crashes, run two smaller heaters instead…beginner4 minEquipmentWater chemistry→?What equipment do I actually need to start a reef tank?Day-one essentials are a tank, heater, light, a way to make saltwater (RO/DI + salt mix), a refractometer, a test kit, a thermometer, a net, and at least one powerhead for flow. A protein skimmer, dosing pumps, a controller, and a refugium are all real upgrades — but they can wait; buying them…beginner5 minEquipment→

Ask the reef

Answers are grounded in the Learn card library and cited — every answer links to the card it came from.
Matching cards
Ask a question or tap a common problem above.
Some links here are affiliate links — AllCorals may earn a commission at no extra cost to you. As an Amazon Associate we earn from qualifying purchases.