Enhancing the growth of coral microfragments using the 'Green Film' Husbandry Method

Scrub, acid wash, and rinse clean the intended vessel prior to startup

Equip the tank with two cleaned and sanitized air stones, an overflow strainer, and PVC seawater outfall

Fill the tank with filtered seawater

Attach an aquarium pump to one side of the tank and direct the water flow towards the opposite wall. Add two heaters connected to a controller and set the thermostat to 28°C. Finally add a blue-tooth temperature logger and 2-3 pieces of healthy CCA to the tank

Secure a tank lid to the vessel using polypropylene rope

Prop the tank lid daily as described in the Tank Maintenance section (see below) for 1 week or until diatoms cover 15–25% of the tank surface

Once noticeable algae appear, remediate the tank as described in the Tank Remediation section (see below), scrubbing it clean, draining it, scouring it with fresh water, and quickly refilling it with filtered seawater

Replace the air stones, aquarium pump, and heaters to continue the selection process

Allow diatoms to repopulate the tank for one week or until 25% of the tank surface is covered with diatoms

Perform a second remediation.  After all other algae is scrubbed away, the ideal outcome from this process is the beginnings of CCA settlement and a light green hue on tank surfaces

Remove the heaters, controller, and aquarium pump. Attach three magnetic grazer cages to the tank walls. Build cages as described in the Constructing Cages section (see below). Add to the tank a total of 40 total trochus snails that do not have macroalgae or cyanobacteria fouling their shells. Include five snails under each grazer cage.

Add new microfragments to the tank as needed, see Tank Maintenance section for proper husbandry (see below). If nuisance algae are successfully controlled through this procedure the tank walls will develop a pronounced coating of green film algae and light CCA roughly two weeks post remediation ( Figure 2 ). This entire process takes about 10–14 days to accomplish. See Figure 3 for a flow chart of the entire procedure

Place CCA pieces in a separate dish filled with filtered seawater and set aside

To remediate a tank scrub the tank clean of all loose adhering and peyssonnelid algae while the tank is still filled with seawater, leave behind only newly settled CCA. Scrub all surfaces thoroughly, including heaters, air stones, aquarium pumps, and temperature probes

Empty the tank. Make sure to keep all surfaces soaking wet throughout the remediation process to preserve live CCA

While all tank drains are open thoroughly scour all surfaces with freshwater using a high-pressure garden nozzle for 2 minutes to deter the recolonization of tank surfaces by fast growing algae and biofilm

Attach a flexible hose to the seawater outfall and scour, rinse, and continuously drain the tank with filtered seawater to flush away residual fresh water

Rapidly refill the tank with filtered seawater while splashing the tank walls.

Scrub the CCA pieces with a toothbrush and scour them with the freshwater hose prior to replacing them

Cut to size and cover the exterior surfaces of the storage tray with vexar mesh to block snails from escaping the cage

Drill 4mm holes in the storage tray at necessary attachment points and secure the vexar to the sidewalls of the tray using cable ties

Mix the 2-part epoxy and completely cover each of the 4-N52 magnets so that no surface is exposed to seawater. Smooth out ridges and fingerprints left in the epoxy to minimize surface area for algal colonization.

While still malleable take two epoxy covered magnets and add enough epoxy to 1 side of the magnet to make an eyelet for a cable tie to attach

Once dry, drill each eyelet with a 4mm hole to allow attachment with a cable tie

Drill a 4mm hole on the rim of each tray in the middle of each of the shortest walls to allow cable tie attachment

Attach one magnet with attached eyelet to each short wall of the storage tray to allow for attachment of the cage to the walls of the tank

Attach the cage to the side of the tank by sandwiching the fiberglass tank wall between the 2 magnets attached to the cage and the 2 remaining magnets

About 3 h after sunrise, prop open and secure tank lids with polypropylene line for ~4 h per weekday and ~2 h per weekend day. Keep lids closed during heavy rains or when the wind direction blows rain directly into each tank

Monitor and record tank temperatures using a blue-tooth temperature logger, salinity using a salinity pen, pH using a pH pen at a standard time during the day and whenever fluctuations in condition are suspected. Temperature should range from 25-27.5°C, Salinity ~35 ppt, and pH ~8.0 for proper coral growth

Blow off any accumulated detritus on growing microfragments using a turkey baster.

Use a small diameter flexible hose to thoroughly siphon out any visible detritus build up, moving tank materials as needed to clean in, around, and under typical accumulation points

Move magnetic grazer cages, housing 5 snails each along the tank surfaces to selectively graze problematic film algae before it can bloom. Any dark colored algae should be targeted and removed with extreme prejudice.

Weekly or after every use replace air stones, bulkhead strainers, seawater outfalls, cages, pumps, and heaters that have become fouled with nuisance algae.  Soak dirty materials in 1:10 muriatic acid solution until fouling organisms are easily scrubbed away (~48 h). Rinse items and let them sun dry before reuse.

As needed replace dirty filter socks to prevent the seawater system from clogging.  Power wash clean, and sun-dry dirty socks in preparation for the next use

Continuously monitor tank temperatures using blue-tooth temperature loggers and adjust waterflow to keep tank temperatures within 25-27.5°C. Temperatures should swing no more than 1°C per day to prevent suboptimal growth.