Parameters
Log salinity, temperature, alkalinity, calcium, magnesium, nitrate, and phosphate with the kit method beside each number. A weekly reef tank test log is boring on purpose—that is what makes drift readable.
Aquarium Care Notes · Reef parameters
Test first. Change slowly.
A weekly log and conservative ranges before you dose.
Here is how to log reef tank parameters safely: write the week’s numbers, read common target ranges, follow a fixed test order, and only then decide whether a small correction—or another retest—is the next move.
Weekly test-order table
Run one session in this order. Select a step to highlight the matching job card below. Ranges are labelled common—they are hobby reference bands, not guaranteed outcomes for any livestock.
| Order | What to log | Common target range | Job focus |
|---|---|---|---|
| Date, sample point, kit method | common Same window each week | Parameters | |
| Salinity (SG or ppt) + instrument | common ~1.024–1.026 SG · ≈32–35 ppt | Salinity | |
| Temperature | common ~76–78°F steady | Parameters | |
| Alkalinity (dKH) | common ~7.5–9.0 dKH | Testing order | |
| Calcium, then magnesium | common Ca ~400–450 ppm · Mg ~1250–1400 ppm | Testing order | |
| Nitrate and phosphate | common NO₃ ~2–10 ppm · PO₄ ~0.02–0.08 ppm | Parameters | |
| Actions taken (or “none”) | assumption One variable · multi-day pace | Dosing assumptions | |
| Retest due | rule Pause before any large swing | Pause-and-retest |
Common target ranges are reference bands many mixed-reef keepers discuss. They are not livestock guarantees, species prescriptions, or a reason to slam a value into the middle of a band in one day.
Published reef programs also set different target recipes for soft-only, mixed, SPS-dominant and frag systems. Red Sea's reef-care recipes are one example: the target follows the system and its goals, not one universal figure. Pick the band that matches your tank and hold it steadily.
Five jobs before you correct the tank
Cards, not a tutorial. Use them with the table above when a reading looks off.
Testing order
Calibrate, then anchors (salinity and temperature), then alkalinity, then major ions, then nutrients. Order cuts false emergencies from evaporation, top-off mistakes, and unsettled samples.
Dosing assumptions
Dosing assumptions on this page are labelled pacing defaults: verify twice, keep salinity stable first, change one variable when you can, and split large gaps across days with a written retest. Not a prescription to dose.
Salinity
Pick one primary unit. Use a conversion only to translate a second instrument—log conflicts instead of blending SG and ppt into one “average.”
Pause-and-retest
A safe change rate for reef parameters starts with stop: repeat the test, confirm anchors, compare the last two weekly rows, then choose at most one small action—or none. Surprise numbers are often method, not catastrophe.
Choose your reef tank measurement task
Start from the task in front of you: confirming a reading and its unit, following a nutrient trend, or identifying brown growth before you treat it. Each link opens the guide that handles that task—read it with the week’s log beside you, and change one variable at a time.
Confirm a reading and its unit
Use these when the number itself is in question—the instrument, the unit, or the range you are holding.
- Salinity for a fish-only tank: choose a stable rangeCompare published fish-only salinity ranges against your livestock and measurement method, then hold one target instead of chasing a single number.
- A low alkalinity reading: verify it, then raise it slowlyLow alkalinity is often a measurement or salinity problem first, so confirm the reading before any incremental, retested dosing.
Follow a nutrient trend and its export
Use these when phosphate or nitrate is drifting and you want the order to change things in.
- Check whether what you see points to high phosphateFast glass film, browning corals and stalled growth are clues, not proof; confirm them with a reading and a trend before correcting anything.
- Bring phosphate down without chasing zeroConfirm repeated readings and their units, check food and detritus inputs, then build export capacity gradually—media such as GFO only when you choose it deliberately.
Identify brown growth before treating
Use this when something brown is spreading on sand, rock or glass and you are not sure what it is.
- Tell diatoms from dinoflagellatesDust, strings, bubbles and overnight change are clues rather than proof; record what you see and confirm the identification before treating either one.
These are reading, logging and identification tasks. This page is not a dosage calculator, does not diagnose disease, and does not set a blanket target range for your tank.
Why keepers trust these notes
Written as a guide
This page turns published husbandry guidance into a step-by-step testing routine and a parameter log you fill in from your own tank. It is not a substitute for your own measurements.
Combinations that fail
We publish the downside: stacking additives, large water changes, media swaps, and new foods in one evening hides which move mattered. The log keeps events separable.
Corrections stay a priority
When a method or range needs an update, the page is corrected and its sources are reviewed. The aim is useful husbandry information without manufactured urgency.
FAQ
How often should I fill the weekly reef tank test log?
Once a week in the same lights-on window is enough for most mixed reefs. A complete row beats scattered mid-week scraps you cannot compare.
Are reef tank parameter target ranges mandatory?
No. Bands on this page are common targets, labelled as such—not guarantees. Keep any tighter personal band in your notes and refuse same-day leaps either way.
What counts as a safe change rate for reef parameters?
Conservative pacing: second test first, salinity stable, one variable when possible, multi-day splits with a written retest. We do not endorse large same-day swings.
Is this veterinary advice?
No. This is husbandry and record-keeping for saltwater keepers. It does not diagnose animals or prescribe medication. For emergencies, contact a qualified aquatic veterinarian.
Where do species and equipment guides live?
Browse the aquarium guides or the tank volume calculator when your log shows a pattern you want to understand more deeply.
Aquarium Care Notes
Keep the log conservative. Open the guide that matches the tank.
Practical aquarium care guides built around testing checklists, parameter logs and step-by-step husbandry routines. Browse local saltwater guides, coral notes, or equipment guidance when the journal points to a deeper read—not a same-day chemistry sprint.