Fish-only Filtration

[LCDRDATA]

My snowflake moray has outgrown his current tank and I will soon be moving him into a standard 55 I recently acquired from another WAMAS member. I am planning to go with a FOWLER-type setup; the current idea is to put eggcrate on the bottom (to protect the glass against any damage from the rock), cover that with about 2.5" or so of live sand (to, among other things, bury the 2" PVC pipe tunnel for the eel to enjoy) and then add on the order of 30-60 pounds of live rock. My question is, what, if any, additional filtration/water quality management will I need? He's been doing fine for the past year in a tank with HOB canister filter and HOB 'fuge; however, those need to remain in place for the corals that will be staying behind. Additionally, I will probably also add one or two tankmates, and am considering something like a puffer, medium-sized tang or trigger -- i.e., something large enough that the eel won't go after it -- and since this will be a FOWLR, "reef-safe" isn't a constraint.

 

So the options would seem to be:

 

1) powerheads for good flow and a clean-up crew only;

2) another canister filter and/or 'fuge (preferable HOB like the current setup); or

3) an overflow box and sump/'fuge (we have a couple 20-30 gallon tanks in the garage the would probably work). I'm not planning on using a skimmer at this time.

 

Anything other than powerheads would require additional purchases, and we're trying to keep that to a minimum; BUT the fish comes first. I also have low-end lighting that should be adequate for a FOWLR (although if anyone would happen to have a ballast for a 48" ODYSSEA twin T5HO, please let me know).

 

Again, the primary question is, what is required to manage water quality in the tank described? Secondarily, I'm open to suggestion as to additional inhabitants that would go well with the moray in the tank described. Thanks!

[surf&turf]

I have an old 48" pc fixture you can have. You can rob the ballasts from it.

[davelin315]

I don't run lights on FOWLR set ups any longer if there's enough light to keep the inhabitants happy (i.e. natural light). This tends to help keep down algae growth as well. As far as a clean up crew, expect it to be eaten if you're going with eels and puffers. Hermits and snails will do OK with eels, but puffers will enjoy crunching them up, especially the hermit crabs during feeding time when they eat stuff on the bottom and the puffer comes around to graze...

 

As far as filtration, your most important aspect is mechanical at this point if it's only fish. I'd be wary of having a sand bed as it will inevitably soak up a ton of gunk from the waste produced by the predators you're thinking of. A bare bottom tank will allow you to harvest any detritus and also run a very high powered pump as a return. I'd go with the sump and overflow and have the return aimed at the bottom to keep things moving. The eel will be fine with rock to hide in and no pipe in the sand - I've kept them for over 20 years and the ones I have currently only have a sand bed temporarily as they are home for the summer - the rest of the time they spend in bare bottom tanks. They don't spend an awful lot of time on the bottom of this tank and spend most of their time curled up in the rock.

[LCDRDATA]

I have an old 48" pc fixture you can have. You can rob the ballasts from it.

I appreciate the offer. I'm not sure when I may get out to your area, but if I'm headed that way I'll ping you beforehand. Thanks.

[LCDRDATA]

A bare bottom tank will allow you to harvest any detritus and also run a very high powered pump as a return. I'd go with the sump and overflow and have the return aimed at the bottom to keep things moving. The eel will be fine with rock to hide in and no pipe in the sand - I've kept them for over 20 years and the ones I have currently only have a sand bed temporarily as they are home for the summer - the rest of the time they spend in bare bottom tanks. They don't spend an awful lot of time on the bottom of this tank and spend most of their time curled up in the rock.

I'll run your comments past my wife, as I think she was especially looking forward to seeing the eel slithering through the pipe (and certainly wouldn't want it showing as a pipe). But she had a good time putting the aquascape together for the current tank, so I may be overstating the point. Have you done anything in particular for your eels in terms of aquascaping? I still like the idea of egg crate to protect the tank from and rockslides, but perhaps that's less of a risk than I'm thinking. Any other pointers? Thank you again.

[Muddy357]

I have the standard 55 hoods and lights from when I bought my 55 if you are interested in them.

[jimlin]

I have some aquarium putty you can use to help glue some of the rocks together to prevent rock slides, although it will make the rock work rather permanent.

[SunWyrm]

My large snowflake digs and has caused some large rocks to slide around even though they were resting on the glass underneath the sand. I wiggled/shook the rocks into place until I knew they were very stable and not going to move from anything she did. She has a large (4/5") pvc tunnel that's hidden by the aquascape on one side, though she digs in the sand wherever she wants. She's also moved some pretty hefty base rock. (To clarify, she did all of this to make a second cave, on the other side of the tank opposite the pvc tunnel I made for her. She also made another tunnel behind that as an extension. This was all over 6 months ago, it's now how she wants it and hasn't moved things around since but it was scary stuff when she was doing it.)

 

In my opinion you should use both egg crate and putty, but more importantly plan the aquascape carefully.

[davelin315]

I tend to put the larger rocks on the top to weigh down the rest of them and then just leave it be. I've currently got a 3' zebra moray and a close to 3' snowflake that have lived in big rock piles. Just make sure that you've got the rocks balanced and put heavy ones on top to hold the bottom ones in place. I find that they don't do a lot of digging if there's ample space to hide between rocks and move around and that digging around and moving rocks tends to happen a lot more often when they are trying to excavate an area that has sand in it and create a new hiding place. When there's no sand to move, they don't do it that often. I don't believe that in the wild they dig in the sand much if at all - they tend to be in the rocks themselves. Only eels other than garden eels I have ever really noticed living in the sand are the zebra morays which tend to just sit there in the sand versus burrowing in...

[Coral Hind]

I would do your option 3 but use a good pre-filter in the sump, bio-balls, and add a skimmer. With the large waste loads you will want a skimmer. As davelin315 mentioned, mechanical filtration to trap the waste before it can start to break down is important.

 

As for the rocks, I wouldn't worry much about them. Just stack them as secure as you can and if they do shift, then they shift. They will eventually find a stable postion and stop moving.

[LCDRDATA]

It looks like we're going to go with a bare-bottom scheme; still trying to find enough rock on a budget. We're going to be putting in ~ 8 linear feet (total) of 2" PVC for the eel to play in. One question my wife had, do we need to drill holes in the pipe to allow for some flow in and out along the length so it doesn't get stagnant in a given section if the eel doesn't choose to go there? If so, how large and with what spacing? Thanks.

Edited August 11, 2012 by LCDRDATA

[davelin315]

I haven't used pipes for eels before except in short (2-3' spans at most with a single elbow or a straight shot only) sections. I would think that you'd want some water movement through the pipes, though, if you have long networks that could trap gas bubbles and detritus.

[smallreef]

I would as long a you are going bare bottom... you should be okay....