Vivarium drainage and misting

Why drainage and misting

The soil in a full tank catches every mist. If that water stays in the core, roots and moss fail from underneath. The drainage layer is a gap between the glass floor and the soil, or a bed of LECA. Water sits there. Soil stays above it.

Misting sets the humidity of the air. Leaves bead, the soil surface stays damp, and the core still breathes. Springtails and isopods live in the leaf litter. Standing water on that litter, and the springtails are gone from the soil within a few days.

The hygrometer bands are already split in the Feedbook. The azure poison dart frog entry is 70–90%. The crested gecko entry is 50–70% by day, with night misting allowed to run higher. The day gecko entry is 60–80%. Mist frequency follows that band. Drainage thickness follows tank width.

Set these two first:

• From the glass floor to the screen: LECA or a false bottom. Keep the water line about 1 cm under the screen.
• Mist onto leaves and the background. Soil surface damp, litter not floating. Between mists, the leaves can dry.

How thick the drainage layer is

A full tank usually uses one of two builds. One spreads LECA across the floor. The other raises an egg-crate deck, and the water sits in the void under that deck. The egg crate is the deck.

LECA

Balls about 8–16 mm. Finer than that, and they mix into the soil. Water sits in the gaps between balls. Once the water line rises past the screen, the soil is sitting in it. Wet LECA is heavy. At 90 cm, the same thickness is lighter as a false bottom than as a full bed of LECA.

False bottom

Short tubes or feet lift the egg crate off the glass. That lift is the depth of the void. Place a foot or a short tube about every 10–15 cm. Wider than that, wet soil bends the crate, and the screen and soil sink into the void. A screen on the crate, holes about 1–2 mm, holds soil back and lets water through. Larger holes let fine soil through. A solid sheet on the screen keeps water from going down, and the void never receives it.

A standpipe in one corner, about 2–3 cm across, reaches the bottom of the void. The water line and the siphon both use that pipe. The void can stay empty. A 1 cm cap of LECA on the screen only supports the screen. Thickness is still the void. Once soil falls into the LECA or the void, water drawn out of it smells. Seat the screen edges first. If soil is still falling through, the water you draw off will smell again.

At 30–45 cm, mostly land, with water only in the drainage layer, use 3–5 cm of LECA. At 60–90 cm, or when the water band is wide and deeper than 8 cm, build a false bottom with the void deeper than the water. When the bank is a shelf over the band, put 2–3 cm of LECA on the shelf, sloped toward the water, and put the void under the band.

On a 45 × 30 cm floor, estimate the drainage layer as 4 cm of water. An empty false bottom holds 5.4 L (45 × 30 × 4 ÷ 1000). The gaps in LECA are about four tenths to half of that layer, so the same height holds about 2–2.7 L. At the same height, a false bottom is lighter and holds more of the extra mist.

One 45 cm set on a ruler: 5 cm of LECA, a screen, 1–2 cm of sphagnum on the screen, 6 cm of soil. The water line sits about 1 cm under the top of the LECA.

When the layer covers the whole floor, use the table for thickness. How deep the band itself is sits in Setting land–water ratio first.

What sits above the drainage

Lay the screen flat, and tuck the edges into the glass. On the screen, sphagnum at 1–2 cm holds fine soil back and keeps a little water. The core does not sit in water. Soil and leaf litter go above that.

Mix bark, tree-fern fiber, sphagnum, and a little charcoal until it feels loose. Aquarium aquasoil stays saturated. On a land shelf it soaks the core.

Leaf litter lies on the soil, loose, about 1 cm. Springtails and isopods stay in that layer. Litter below the water line means the layer is in the water. Isopods need a damp hide and also a piece of bark or wood that can run drier. That piece sits at the edge of the spray, not directly under a nozzle.

Place cushion moss whole, on this soil. Split Hypnum into a thin carpet, 0.5–1 cm. Both stay damp on the surface, with air underneath.

In a tank 30 cm tall, 3 cm of LECA, 1 cm of sphagnum, and 4 cm of soil put the land surface about 8 cm off the glass. Stack more, and the floor an animal can use in a front-opening door sits higher. In a tank 45 cm tall, 5 cm of LECA, 1–2 cm of sphagnum, 6 cm of soil, and 1 cm of litter put the land about 13–14 cm off the glass. Plants and the background start above that.

The order stays fixed. LECA or the false bottom, then the screen with edges seated, then sphagnum, then soil and the slope of the bank. After the standpipe or overflow is set to the water line, run one mist with the tank empty of litter. Water should reach the drainage layer and the soil surface should not puddle. Then add litter and moss.

Hand mist or a timer

A 30 cm or 45 cm tank can stay on a hand bottle. Stop when the leaves bead. Hold the nozzle about 20–30 cm from the leaves, and pass once without pausing on one clump. When beads join into a stream and puddle on the soil, that pass ran long. From 60 cm, a hand bottle often only wets the front door, and the back wall and upper leaves are still dry by noon. That width moves to a timer. Aim nozzles at leaves and the background, and leave the standpipe outside the spray.

One nozzle covers a run of about 30–45 cm. A 60 cm tank uses 2. A 90 cm tank uses 3–4. Front and back both get spray. A cork or foam background soaks up part of the mist that hits the wall. The back nozzle uses the longer end of the seconds in the table. The front nozzle still stops when leaves bead.

The table is a starting schedule for the 70–90% band, the azure poison dart frog entry. Seconds stop when leaves bead and litter does not float. If the hygrometer spends the whole interval outside the band, add one short mist. Do not double the seconds in one step.

On the same nozzles, a gecko setup turns the daytime pass off, or cuts it very short.

Match the count to the Feedbook band:

• Crested gecko: night misting can run above 70%. By noon, back to 50–70%.
• Day gecko: mist at dawn. Leaves dry by afternoon. Humidity stays at 60–80%.
• Azure poison dart frog: the reading can drop a few points between mists. The full day stays at 70–90%. The core stays unflooded.

Leave a slot of ventilation. With the slot shut, a short mist still beads the glass all day. Opened to a full screen top, a timed mist on a 60 cm tank does not hold 70%. Put the hygrometer at leaf height, out of the nozzle’s line. A reading taken the moment misting stops often sits above 90%. The daytime number for that band is the reading 1–2 hours later. The mist reservoir holds water that has stood or been filtered free of chlorine, the same water used to top up the band.

In the first week after the build, check three things each day: the water line in the standpipe, whether leaves are dry at noon, and the hygrometer 1–2 hours after a mist. A line that rises every day, with leaves still wet at noon, means the mist is too frequent, or the outlet is not in yet. A line that barely moves, with a pale back wall, means a nozzle is missing that area.

Overflow and the water band

If the only water is inside the drainage layer, read the line in the standpipe. When water touches the screen, siphon a section back to about 1 cm under the screen. On a 30 cm, mostly-land tank, that check is usually once a week. Mist more often, and the check moves to every two or three days.

If the tank has a water band, depth follows the three bands in Setting land–water ratio first: 1–4 cm, 4–8 cm, and 8–15 cm. Misting raises that band over time.

A 45 cm tank, 30 cm front to back, water 22 cm wide and 6 cm deep, is about 4 L. Each extra centimetre on that surface is about 0.7 L. Mist with nowhere to leave piles onto that 0.7 L. An extra 0.7–1.4 L in a week raises the line 1–2 cm, and the foot of the bank starts to sit in water. On the same floor, LECA holding about 2–2.7 L reaches the screen in a week or two at that rate. A false bottom of 5.4 L takes longer to reach the screen on the same mist. Seconds set the leaves. The water line is still read in the standpipe.

The outlet:

• Overflow: a divider or standpipe set at the target line. Extra water leaves at the pipe. A return pump sends water back to the mist reservoir or the band. The pipe sets the line.
• No overflow: siphon on the schedule above. What comes out is the extra section. Every week or two, also draw off about half through the standpipe and replace it with fresh water. If what comes out smells, check the screen for soil, then shorten that interval.

Measure the standpipe mouth from the glass floor. For a target depth of 6 cm, the mouth is at 6 cm, and still under the screen. Soil on the screen stays above that line. Soil on the bank stays above the band. Drainage on the bank slopes toward the water, 2–3 cm thick. When the drainage covers the whole floor and the band is 8 cm or deeper, the false-bottom void is about 1 cm deeper than the water, so soil does not take water in from the side. At 90 cm, mostly water, 12–20 cm deep, leave that same extra 1 cm in the void.

When it does not line up

These five rows are the usual look when drainage and misting do not line up. The hygrometer can still sit in range while the core is already flooded.

Checking it in the studio

Magic Amphiscape makes a full-tank product shot. The bank and the waterline are in the picture. LECA thickness, how many centimetres the egg crate sits off the glass, and seconds per nozzle are not marked on it.

Set habitat type, tank size, and land / water ratio first. Those three decide whether a water band is there, and about how deep it is. A dart-frog vivarium is often half and half, with the band at 4–8 cm: 2–3 cm of LECA on the bank, and an overflow or standpipe on the water side. A bioactive gecko vivarium is often mostly land, with water as a shallow dish or only inside the drainage layer, and the daytime mist turned off. A stream riparium and a mangrove tank are often mostly water, 8 cm or deeper, with the false-bottom void about 1 cm deeper than the water. Drainage and misting use the tables above, on the real tank. The hygrometer is checked against the Feedbook.

Open Magic Amphiscape, set habitat type, tank size, and land / water ratio, then put drainage and misting on a ruler from this page. How much of the floor the band takes is in Setting land–water ratio first.

Details to add? Tell us via Contact.

2026-10-13