Dosing Checklist for Tank Automation

Match the method to coral demand, evaporation rate, and pH goals. Two-part works well for predictable daily consumption, while kalkwasser is limited by evaporation but can help raise low pH in tightly sealed homes.

Test alkalinity at the same time each day for 5-7 days with no major water changes to calculate true daily demand in dKH. For mixed reefs, swings over 0.3 dKH per day usually justify automated dosing over manual additions.

Define realistic targets such as alkalinity 7.5-9.0 dKH, calcium 400-450 ppm, magnesium 1250-1400 ppm, pH 7.8-8.4, and salinity 1.025-1.026 SG. Automation should maintain a stable range, not chase an exact number with constant corrections.

Subtract rock, sand, and equipment displacement from display plus sump volume before using any dose calculator. Overestimating true water volume is one of the most common reasons automated corrections overshoot.

Magnesium consumption is usually much slower than alkalinity and calcium, so many reefers automate only periodic Mg additions. If you do automate it, schedule fewer, larger doses and verify that your pump can reliably deliver that volume.

If your tank runs low pH and high indoor CO2, schedule kalkwasser or alkalinity-heavy dosing at night to offset the normal pH drop. If nutrients are ultra-low and coral growth is stalled, avoid increasing dosing blindly before checking nitrate and phosphate.

Peristaltic pumps with known ml-per-minute output are preferred for reef automation because they can deliver many small doses across 24 hours. Avoid generic pumps with poor repeatability if you are trying to hold alkalinity within 0.2-0.3 dKH.

Run the pump for a fixed interval and measure output in milliliters using a graduated cylinder or lab cup, then enter the actual rate into your controller or app. Recalibration every 1-3 months is important because tubing wear changes output over time.

Dose into an area with strong water movement, usually near the return chamber or skimmer section, to prevent localized precipitation. Never drip alkalinity and calcium solutions into the same small compartment or onto heaters, probes, or pump intakes.

Keep dosing container liquid levels below the tank or use anti-siphon fittings and check valves where appropriate. Poor tube routing can create gravity-fed overdoses even when the pump is off, especially with kalk reservoirs placed high above the sump.

Kalkwasser and alkalinity concentrates can temporarily spike local pH and coat nearby sensors, causing false readings and nuisance alerts. Position dosing outlets away from probes, ATO optical eyes, and roller mat sensors to reduce fouling and bad data.

Clearly mark alkalinity, calcium, magnesium, and kalk lines so maintenance or refills do not cross-connect channels. A swapped alk and calcium line can lead to rapid precipitation, cloudy water, and severe instability.

Instead of one or two large events, divide the total daily amount into 8-24 increments to flatten parameter swings. This is especially useful in SPS systems where alkalinity stability often matters more than the exact target number.

Stagger the two channels by at least 10-30 minutes so concentrated solutions do not meet in the sump and precipitate. In compact sumps or low-flow systems, longer separation is often safer.

Configure hard caps for each additive based on expected consumption plus a small buffer, such as 10-20 percent above normal. This prevents runaway dosing if a schedule duplicates, a virtual outlet sticks on, or a pump head calibration is entered incorrectly.

Pause kalk additions if tank pH exceeds a chosen ceiling, often around 8.40-8.50 depending on your normal range. This simple rule can prevent dangerous overdoses during ATO failures, stuck relays, or low evaporation periods.

If kalkwasser is delivered through top-off, monitor seasonal evaporation because winter and summer demand can differ dramatically. Tanks in humid rooms may suddenly receive less kalk and drift down in alkalinity even when the ATO is operating normally.

Schedule a higher percentage of kalk or alkalinity additions during the dark cycle when pH typically falls. This strategy can reduce daily pH swing without making daytime pH excessively high.

Temporarily pause dosing during sump shutdowns, return pump maintenance, or water changes so additives are not dumped into stagnant compartments. This is especially important for concentrated alkalinity solutions that can precipitate instantly in low flow.

Even if you use automated testers or controller integrations, verify daily with a trusted hobby kit or digital checker while dialing in the schedule. Alkalinity is the fastest moving major parameter, so it is the best early indicator that the automation is behaving correctly.

Calcium and magnesium change more slowly than alkalinity, so weekly checks are usually enough while stabilizing. If calcium drifts below 400 ppm or magnesium drops under 1250 ppm, recalculate balance rather than only increasing the alkalinity dose.

Review 24-hour pH graphs to see whether your schedule is reducing normal overnight dips or creating spikes. A stable pattern is more useful than chasing the highest possible pH, especially if livestock already looks healthy.

Smart level sensors, scales, or even simple graduated containers can reveal when a pump is overdosing or not drawing fluid. Sudden reservoir depletion is often the first sign of a stuck doser, siphon issue, or programming error.

Build a small set of high-value alerts instead of dozens of notifications that get ignored. Prioritize events that threaten chemistry stability, such as pH above 8.5 with kalk enabled or no dosing activity during a normal dose window.

Polyp extension, tip burn, tissue recession, and coralline growth all provide context that sensors cannot. If alkalinity looks stable but SPS tips are burning, check whether nutrient levels are too low relative to your dosing-driven growth rate.

Peristaltic tubing hardens, flattens, and drifts over time, which reduces dose accuracy. Replace wear parts according to the manufacturer schedule or sooner if calibration starts shifting more than expected.

Always use the same recipe, water volume, and additive brand unless you intentionally recalculate the dose. Changing concentration without updating the controller is a common automation mistake that causes unexplained parameter swings.

Undissolved kalk paste and impurities collect at the bottom and can clog lines or alter saturation if neglected. Periodic cleaning also prevents optical or float sensors from sticking in kalk-fed top-off systems.

Do not assume alerts or shutoffs work because they were programmed once. Trigger the condition intentionally during a supervised test to confirm pumps stop, notifications send, and recovery logic behaves the way you expect.

Keep measuring syringes, additives, and a written daily baseline dose available in case the doser, controller, or Wi-Fi fails. A simple manual fallback prevents panic corrections during power or network interruptions.

Revisit dosing rates after adding fast-growing SPS colonies, changing salt mix, increasing lighting PAR, or improving nutrient export. Higher PAR and stronger coral growth often increase alkalinity and calcium demand within days to weeks.