FAULT ISOLATION MANUAL · CARBONATE SYSTEM — ALKALINITY

ALK-001 · Alkalinity decreasingv1.4.1

Alkalinity falls between doses faster than expected. This sheet walks the same isolation logic an aircraft maintenance manual uses: confirm the reading, rule out what confuses it, verify what the equipment actually delivers, and only then decide between consumption and precipitation. Answer each numbered block and the sheet lights the path.

WHAT YOU'LL NEED

Your alkalinity test kit (plus a second kit or fresh reagent)
3+ daily tests, same kit, same time of day
Graduated container, if you run a dosing pump
Your tank journal

JavaScript is off, so the interactive sheet can't run — the complete printed logic is below. Start at block 1 and follow the YES/NO links. Nothing about your tank is inferred or stored.

Block 1 — Have you confirmed the reading with a second test (a different kit, or fresh reagent)? (Note: Reagent age is the number one false alarm in alkalinity testing.)
YES → block 2 · NO → block 31

Block 2 — Is alkalinity dropping MORE than 0.3 dKH per day, across at least 3 daily tests taken with the same kit at the same time of day? (Note: 0.3 dKH/day is BioForge diagnostic policy: an investigation trigger, not a biological definition of abnormal. Readings from different kits or different times of day are not comparable and do not count toward the 3.)
YES → block 3 · NO → block 27

Block 3 — During that SAME trend window: any water change, salinity adjustment, dosing-program change, or notable top-off/volume change? (Note: Replacement water with different alkalinity, a salinity shift, or a changed dose can create an apparent decline that has nothing to do with tank demand, delivery, or precipitation.)
YES → block 4 · NO → block 5

Block 4 — TREND WINDOW CONFOUNDED — the decline cannot be attributed while the window contains an intervention. Re-establish the trend: 3 daily tests, same kit, same time of day, with no water changes, salinity adjustments, or dosing changes. If the decline reproduces, return to this procedure. (Verify — 3 days, ALKALINITY: Three comparable daily tests in an intervention-free window still show decline greater than 0.3 dKH/day)
END — ESCALATE RETEST

Block 5 — Is alkalinity currently ABOVE your tank-type target range: 8–10 dKH (mixed reef) or 7–9 dKH (SPS-dominant)? (Note: A fall from an elevated level is dispositioned differently: no dose-raising action is safe above range.)
YES → block 6 · NO → block 7

Block 6 — ABOVE TARGET AND FALLING: do NOT dose upward and do NOT use correction mode. Identify what produced the elevation (a recent correction overshoot, a dosing increase, a high-alkalinity salt mix) and log it in your journal. Monitor daily while the level comes down toward range. (Note: A decline from elevated can be ordinary consumption after prior overdosing, a programmed dosing reduction, or a delivery change. Nothing here presumes precipitation. The tank is not required to reach range in three days: if verification fails, the level is reclassified fresh at the range check before any further step.) (Verify — 3 days, ALKALINITY: At the three-day reassessment: decline has slowed to 0.3 dKH/day or less, with no upward dosing in the interval)
verified resolved → done · problem continues → block 5

Block 7 — Does the tank have ANY active alkalinity supply: liquid dosing pump, kalkwasser (ATO or manual), calcium reactor, or regular manual dosing? (Note: Alkalinity can enter the tank without the owner thinking of it as "dosing." Only a true absence of supply counts as no supply.)
YES → block 8 · NO → block 10

Block 8 — Is that supply a liquid dosing pump (peristaltic or DC doser)? (Note: The delivery check below, timed container runs, quantifies a liquid dosing pump only. It cannot verify kalkwasser saturation, calcium reactor effluent, or manual dosing consistency.)
YES → block 13 · NO → block 9

Block 9 — UNSUPPORTED SUPPLY METHOD — this revision of ALK-001 can verify delivered alkalinity for liquid dosing pumps only. With kalkwasser, a calcium reactor, or manual dosing, a delivery shortfall cannot be excluded or confirmed here, so this procedure stops rather than guess. Log your supply method and the confirmed decline in your journal; a future revision will add calibration procedures for these methods. (Note: If several parameters are drifting at once, not just alkalinity, a full ICP analysis may be warranted on its own merits. That is a separate decision, not this procedure's exit.) (Why this procedure stopped: ALK-001 has no calibration procedure for kalkwasser, calcium reactor, or manual-dosing delivery: the timed-container check quantifies liquid dosing pumps only. This is a Manual coverage gap, not evidence of a tank fault requiring multi-parameter analysis.)
END — UNSUPPORTED METHOD

Block 10 — Is alkalinity currently BELOW the target range? (Note: Below range adds a second task, restoring the deficit, on top of establishing supply.)
YES → block 12 · NO → block 11

Block 11 — NO ALKALINITY SUPPLY: consumption with no replacement. Set a maintenance dose sized to measured daily demand: enter tank volume and measured daily drop in the dosing calculator. (Verify — 3 days, ALKALINITY: Three comparable daily tests (same kit, same time of day) show decline of 0.3 dKH/day or less and alkalinity holding inside the target range)
verified resolved → done · problem continues → block 5

Block 12 — NO SUPPLY AND BELOW RANGE: two separate tasks. First restore the deficit with correction mode, which paces the raise at safe daily rates. Then set a maintenance dose sized to measured daily demand (tank volume + measured daily drop) in the dosing calculator. (Note: Correction mode restores a level; the maintenance dose matches ongoing demand. Neither substitutes for the other.) (Verify — 3 days, ALKALINITY: Alkalinity back inside the target range and three comparable daily tests show decline of 0.3 dKH/day or less on the maintenance dose)
verified resolved → done · problem continues → block 5

Block 13 — Verify actual delivered dose. Run your doser into a graduated container for a timed 60-second run, twice. Convert the measured mL/day into dKH delivered with the calculator, then return here.
then → block 14

Block 14 — Across BOTH timed runs, does measured pump output match the programmed dose within ±10%? (Note: ±10% is BioForge equipment-check policy. A single run must not isolate a delivery fault: peristaltic tubing fatigues gradually and output varies run to run.)
YES → block 16 · NO → block 15

Block 15 — DOSING DELIVERY SHORTFALL: the tank never received the programmed dose. Recalibrate the doser or replace fatigued tubing, then reprogram to the verified output and re-run the timed-container check. (Note: Peristaltic tubing loses accuracy long before it visibly fails. Recalibrate on a schedule, not on symptoms. Verification here is the doser's measured output: the alkalinity trend is re-checked downstream once delivery is proven.) (Verify — 1 day, DOSER OUTPUT: Two fresh timed 60-second container runs each match the programmed dose within ±10%)
verified resolved → done · problem continues → block 5

Block 16 — Is calcium ALSO falling across the SAME test days: measured with the same calcium kit each time, with no change to calcium dosing and no water change during the interval? (Note: Balanced consumption draws roughly 7.1 ppm calcium per 1 dKH of alkalinity. That ratio is theoretical: test error, water changes, unequal dosing, and precipitation all distort it. Treat agreement as corroboration, never proof; and only comparable, confound-free calcium readings count.)
YES → block 17 · NO → block 20

Block 17 — Is alkalinity currently BELOW the target range? (Note: Below range means two tasks: restore the deficit AND match demand. In range means one: match demand.)
YES → block 19 · NO → block 18

Block 18 — PATTERN CONSISTENT WITH BIOLOGICAL CONSUMPTION exceeding your dose. Raise the MAINTENANCE dose to match measured daily demand: tank volume and measured daily drop in the dosing calculator. Correction mode is not the tool here: the level is in range; there is nothing to restore. (Note: This corroborates consumption after test error, confounds, missing supply, and delivery shortfall were eliminated. It does not isolate by ratio alone.) (Verify — 3 days, ALKALINITY: Three comparable daily tests show decline of 0.3 dKH/day or less and alkalinity holding inside the target range on the new maintenance dose)
verified resolved → done · problem continues → block 20

Block 19 — CONSUMPTION EXCEEDS DOSE AND THE LEVEL IS BELOW RANGE: two separate tasks. First restore the deficit with correction mode, which paces the raise at safe daily rates. Then set the maintenance dose to match measured daily demand (tank volume + measured daily drop) in the dosing calculator. (Note: Correction mode restores a level; the maintenance dose matches ongoing demand. Doing only one leaves the fault active.) (Verify — 3 days, ALKALINITY: Alkalinity back inside the target range and three comparable daily tests show decline of 0.3 dKH/day or less on the maintenance dose)
verified resolved → done · problem continues → block 20

Block 20 — Is pH persistently at or above 8.5 across your daily tests, taken at the same time of day with a calibrated probe or fresh kit, not a single spot reading? (Note: pH swings daily with lighting and CO2. One high reading at peak photosynthesis is normal; a persistent elevated baseline is what raises precipitation odds: it does not isolate on its own. 8.5 is BioForge fault-specific diagnostic policy for this precipitation investigation, applied to both tank types: it is not an ICP classification boundary, and a finer tank-type split is below field measurement resolution.)
YES → block 22 · NO → block 21

Block 21 — Is white crust present on heaters, pump impellers, or plumbing? (Note: Presence alone is not corroboration: deposits persist from earlier conditions. The next step tests whether deposition is CURRENT.)
YES → block 22 · NO → block 25

Block 22 — PRECIPITATION CHECK: existing crust can be historical, and high pH alone does not isolate precipitation. Establish a deposition baseline: clean or photograph a marked section of heater or impeller surface, log it in your journal, and re-inspect after 48–72 hours while the decline continues. (Note: Only NEW deposition during the fault window counts as corroboration.)
then → block 23

Block 23 — Is NEW white deposition forming on the marked section within the re-inspection window?
YES → block 24 · NO → block 25

Block 24 — PATTERN CONSISTENT WITH ABIOTIC PRECIPITATION: alkalinity is likely leaving solution as carbonate rather than feeding coral. Reduce the drivers: split the daily dose into smaller portions dosed into high flow, keep alkalinity in the lower half of your target range, and keep the marked section under observation as you verify. (Note: Corroborated pattern, not proof: if verification fails, continue the procedure rather than repeating the mitigation. "Lower half of your target range" is BioForge action policy for precipitation mitigation, not a cited chemistry constant.) (Verify — 3 days, ALKALINITY: No new deposition on the marked section at re-inspection and decline slows to 0.3 dKH/day or less across three comparable daily tests)
verified resolved → done · problem continues → block 25

Block 25 — In the last two weeks: new filtration media, new rock added, or anything curing in the system?
YES → block 26 · NO → block 33

Block 26 — RECENT SYSTEM CHANGE UNRESOLVED — a change in the last two weeks coincides with the decline, but this procedure cannot attribute the loss to it or quantify it from alkalinity readings. Do not hold dose on an assumption during a confirmed rapid decline. A full 38-parameter ICP analysis with photo and history context is the next step; note the recent change when you submit. (Why this procedure stopped: A recent system change is an unresolved confounder: this procedure cannot attribute or quantify its effect from alkalinity readings alone, and a confirmed rapid decline should not be waited out on an assumption.)
END — ESCALATE DECODE

Block 27 — Is your alkalinity still inside your tank-type target range: 8–10 dKH (mixed reef) or 7–9 dKH (SPS-dominant)?
YES → block 32 · NO → block 28

Block 28 — Is alkalinity BELOW the range (rather than above it)?
YES → block 29 · NO → block 30

Block 29 — BELOW TARGET RANGE, DRIFT NOT ABNORMAL: restore the level with correction mode, which paces the raise at safe daily rates. Leave the maintenance dose unchanged; consumption is inside the trigger. (Verify — 3 days, ALKALINITY: Alkalinity back inside your tank-type target range and holding across three comparable daily tests)
verified resolved → done · problem continues → block 2

Block 30 — ABOVE TARGET RANGE, DRIFT NOT ABNORMAL: do NOT dose upward; correction mode only raises alkalinity and has no place here. Let normal consumption bring the level down into range and test daily while it settles. (Note: Falling from an elevated level toward range is the system self-correcting. Chasing the number upward re-creates the elevation.) (Verify — 3 days, ALKALINITY: Alkalinity moving down toward or inside your tank-type target range with no upward dosing, and decline still 0.3 dKH/day or less)
verified resolved → done · problem continues → block 2

Block 31 — Retest before troubleshooting: a single reading is not a trend. Confirm with a second kit or fresh reagent, then return to this procedure. (Verify — 2 days, ALKALINITY: A second kit or fresh reagent reproduces the decline across two daily tests)
END — ESCALATE RETEST

Block 32 — ALK-001 NOT ACTIVE — the decline does not exceed the 0.3 dKH/day investigation trigger and alkalinity is inside your target range. That establishes only that the trigger is not met; it does not identify the cause of routine consumption. Log the trend in your journal: a recorded baseline makes the next investigation faster.
END — NO FAULT

Block 33 — This procedure cannot isolate the fault from alkalinity readings alone. A full 38-parameter ICP analysis with photo and history context is the next step. (Why this procedure stopped: Confound window, supply, delivery, consumption corroboration, and current-deposition precipitation checks completed without isolating a cause: multi-parameter interaction beyond single-fault isolation.)
END — ESCALATE DECODE