Aquarium teardown planner
Emptying a tank is the riskiest thing most of us do to an aquarium — and the danger is rarely the lift. It is the job overrunning while livestock sit in a bucket nobody has checked for two hours.
The teardown itself is the same job either way. The checks at the start and the put-back at the end are what differ.
“People on the job” includes you — enter 1 if you are doing it alone.
This is what sizes the containers you will need. Add a row per group and give a rough adult length — it does not need to be exact.
Tell us what you can actually house them in. A spare aquarium or a pair of 75 L tubs changes the answer completely — and spreading fish across half a dozen small containers is a worse plan than using two big ones.
Answer all of these before you buy anything or move any water. Most teardown guides skip this part, which is why people discover the problem with the tank drained and the fish already in a bucket.
Sized from your own numbers. Nothing about this job improves by starting short of kit.
The whole job in one screen, before you start ticking through it.
Tick in whatever order suits you — real jobs do not run in a straight line. Progress saves instantly, so you can lock your phone, lose signal, or come back tomorrow.
Fish gasping at the surface in the container. Oxygen, not ammonia, is almost always the cause. Add a second airstone immediately, take the cover half off, and do a 30% change with temperature-matched water. Stop feeding entirely.
A seam is weeping after refill. Drain below the leak now — not later. A weeping seam does not heal, and a failed one empties the tank in minutes. Dry it fully, reseal inside, cure 7 days.
You are running out of time or daylight. Stop at a safe holding state rather than rushing the lift: livestock in an aerated, covered, insulated container; filter media submerged in tank water; plants submerged and shaded; the tank dry and stable on the floor or the stand, not balanced between them. All of that will hold overnight. A rushed lift will not be undone.
The tank is chipped or cracked. Do not refill it to test. A chip on an edge under load propagates. Get it assessed empty.
Substrate has gone anaerobic and smells of sulphur. Keep it out of the livestock containers, rinse it in old tank water rather than tap, and expect an ammonia spike. Test daily.
The job is not finished when the water is back in. This is where a teardown quietly turns into a cycle crash.
How the numbers work
Containers are sized on ammonia, not oxygen. An airstone removes the oxygen ceiling almost entirely — 49 g of fish in 40 L has around 17 hours of dissolved oxygen before you add any aeration at all. What actually accumulates over a few hours is ammonia, so the volume needed scales with how long your fish are out, not with a flat rule. A 3× stress factor is applied because netting and crowding raise excretion sharply, and a floor of 2.5 cm of fish per litre keeps some swimming room and thermal mass.
You do not need to save all the water. Nitrifying bacteria live on filter media and substrate surfaces, not floating in the water. Saved water avoids a sudden parameter swing; it does not preserve your cycle. Keep enough for livestock and plants, refill the rest at matched temperature, and treat it as a large water change.
The clock escalates because duration is the real risk. The lift gets the attention, but the common failure is a container cooling with a knocked-off airstone while everyone looks at the tank. The timer starts when you tick livestock out and escalates to a recommended container water change past four hours.
Time estimate. Fixed overheads for setup, reconnection and final checks, plus a lift allowance when the tank moves; then variable time from your water volume, substrate volume, plant count and livestock count. Extra hands speed up draining, substrate and refilling but barely touch catching fish or replanting. A 10% contingency is added deliberately — under-promising on a job with livestock in buckets is the one error with a cost attached.