After months of planning and anticipation, the new slug facility is up and running at Shady Grove.  The original “system,” if you could call it that, was a 20 gallon long tank with an Evergrow LED fixture to supply light and a Hydor Ekip thermopump to provide heat and circulation.  It worked fine in terms of egg production, and the adults seemed quite happy.  The new system has a separate growout tank for baby slugs, a sump for equipment such as the heater and an automated topoff system to make up for evaporation. It will also have a hatchery tank, in which the eggs and veligers will have constant circulation of fresh, pest-free water.

After the shelf was built and painted, the system was set up in one of the lab spaces (no carpet, spill kits at the ready).  For this test, only the 15 gallon broodstock tank and sump were used.

Preliminary test broodstock and sump

Then water was added…

Wet test, broodstock and sump

The plumbing and hardware appeared to function adequately, so it was ready to be set up in the office.  The rack was moved into place and the sump was filled from the Bryopsis growout tank (photo below).  For the final fill, I waited until I could get started first thing in the morning, so that I would have most of a day to keep an eye on it in case of unanticipated redirection of flow (i.e., flooding).

Box of Slugs 1.1, ready to be filled with water and livestock.

Then it was time to commit.  Water, sand, plants, and slugs all had to be moved in an orderly way.  In an hour or so, everyone was settled in their new homes.  The seahorse had been moved to Box of Slugs 2 to minimize her stress, but all of the adult slugs, the broodstock, took their place in the 15 gallon tank on top.

Box of Slugs 1.1, up and running.

So there it is.  The main slug tanks, for adult broodstock and growing youngsters, now have dividers to keep the Bryopsis from completely overwhelming the other algae.  Heater, topoff valve, and pump are in the sump, where they can’t bother the slugs.  Flow from the sump to the rest of the system passes through a reactor filled with activated carbon, to prevent possible inhibition of slug growth by secretions from the algae.  It should also reduce any odors produced by a system packed with seaweed.  Having a sump makes it easier to dose with calcium, bicarbonate, nitrate and phosphate without worrying that some is getting dumped on the slugs’ heads.  As an added bonus, the tank is not taking up valuable real estate in the middle of my office.

The slugs seem happy in their new home.  They are exploring, feeding, and starting their mornings by basking in the sun.

E. clarki in new home, checking temperature

Elysia clarki greeting the morning sun in new home

Now that phase 1 of B.o.S 1.1 is finished, I will be adding more macroalgae and move some of the the E. clarki youngsters from Box of Slugs 2 into the growout tank.  The final phase will be to get the hatchery on line, to have more control of the timing and numbers of baby slugs.