Pests
Aiptasia Why One Turns Into a Hundred, and What Actually Kills It
One glass anemone looks harmless until it's thirty. Here's how to spot aiptasia early, why it spreads so fast, and which treatment actually works.
ReefDiary Blog
Aquarium tracking guides for healthier tanks
Practical guides for reef and freshwater keepers who want clearer parameter history, better maintenance routines, and a more useful tank record. Browse 19 guides below.
Hobbyist
Reef Aquascaping How to Design Rockwork That Still Works in Three Years
Most reef tanks are scaped once, in a hurry, on the day the rock arrives and lived with for years. Here's how to design a scape that suits your tank instead.
Diseases
Living With Ich How to Manage Marine Ich in a Display Reef You Can't Tear Down
You can't put copper in a reef and you can't catch a tang out of 200lb of rock. Here's what actually works when ich shows up in a display tank you're not willing to dismantle.
Water
Salinity The Reef Tank Parameter Your Hydrometer Is Probably Lying About
Every other parameter you test is measured as a concentration in saltwater. If the salinity is wrong, every one of those numbers is wrong with it.
Hobbyist
Magnesium The Reef Tank Parameter That Fixes the Two You're Actually Watching
If your alkalinity keeps sliding no matter how much you dose, magnesium is usually the parameter quietly causing it. Here's what it does and where it should sit.
Livestock
Wrasses Explained The Types, Care Levels, and What Makes Them Special
Fairy, flasher, sixline, melanurus, leopard reef wrasses look similar in a fish store tank but couldn't be more different once they hit your reef.
Hobbyist
PAR, Not Watts How to Actually Light a Reef Tank for Coral Placement
Watts and Kelvin tell you almost nothing about whether your light can grow coral. Here's how PAR actually works, what each coral type needs, and how AI, EcoTech, Kessil, and Orphek fixtures compare.
Parameters
Why Your Reef Tank's Trace Elements Deserve an ICP Test (And What Each One Actually Does)
Calcium and alkalinity get all the attention, but a reef tank runs on two dozen trace elements you can't see or smell and can't dose safely without knowing where you stand.
Parameters
Calcium 101 Why Your Reef Tank Is Way Thirstier Than Your Old Goldfish Bowl
Somewhere in every reefer's origin story there's a moment of genuine confusion: "Wait, I need to dose what now?" You spent years keeping freshwater tanks without ever thinking abou
Livestock
Mandarin Fish Explained Types, Care Level, and Why They're So Hard to Keep Alive
The most photographed fish in the hobby is also one of the easiest to slowly starve here's what green, spotted, and psychedelic mandarins actually need.
Hobbyist
Your Clean-Up Crew Is Either Working or Just Along for the Ride
Not every snail earns its keep. Here's which clean-up crew members are actually doing a job in your tank versus just decorative crawlers.
Parameters
Why KH Is Actually the Foundation of a Stable Reef Tank
KH (carbonate hardness) is what keeps your pH stable. Ignore it and everything else falls apart. Here's why.
Hobbyist
The Reefer Rollercoaster Why We Keep Doing This to Ourselves
One day you're mourning a dead acan, the next you're grinning at a tank full of open polyps. Here's why reefkeeping wrecks us and we love it anyway.
Livestock
Tangs: Beautiful Reef Fish with Big Personalities and Big Needs
Tangs, also called surgeonfish, are some of the most eye-catching fish in the marine aquarium hobby. They bring colour, movement, and constant grazing behaviour to a reef tank. But
Hobbyist
The Coral That Wouldn't Open A Story About Flow, Not Bad Luck
A sad, shrunken coral isn't always sick sometimes it's just sitting in the wrong current. Here's how to read the signs and zone your tank properly.
Hobbyist
The Ich Outbreak That Took My Tangs And Why the Wrasse Made It Out Alive
I lost my black tang, yellow tang, Atlantic blue tang, and my storm clowns to an ich outbreak in one bad stretch. Here's what happened, why the wrasse survived, and what I'm doing differently.
Parameters
The CO2 Scrubber That Stopped My pH Swings And Why I Finally Started Tracking
My pH was all over the map until I realized room air CO2 was the culprit. An Icecap CO2 scrubber fixed it, and tracking finally proved it." metaDescription: "How an Icecap CO2 scrubber stabilized pH by removing CO2 from incoming air, and why parameter tracking revealed the before-and-after difference.
Hobbyist
We Tried Four Other Reef Tank Apps Before Building My Tank Log in ReefDiary
Reef Trak, Aquarimate, NextUpReef, ReefBay here's what each one actually does well, where they fall short for a serious reef tank, and why I ended up keeping my logs in ReefDiary.
Hobbyist
Why Water Parameter Testing Alone Isn't Enough And What Tracking Actually Gets You
Most reef tank problems don't start on the day you notice them. They start weeks earlier, as a slow drift in alkalinity or a nitrate curve creeping upward one test at a time invi