Fuge with cryptic zone

[Gonzobob]

Hey guys, I'm finally getting some of my tanks ready to move to the new fish room which means I have the opportunity to do some tank and sump consolidation.

I'll be consolidating 3 nanos into a single 100 gallon tank and finally moving my nems into a single 40 gallon breeder.

For these two tanks I want to setup a single large sump / refugium. As I have a 120 gallon Rubbermaid vat currently in use as a live rock vat it seemed like a good place to start.

Key goals for the sump / refugium are as follows:

Provide a cryptic zone for water quality improvement and copepod propagation.

Provide a specific location for macro and frag grow out

Provide sufficient area for live rock for additional biological filtration

The design I have so far is shown below:

Any thoughts or suggestions would be welcome.

[Mr Cob]

looks nice, one thought that crossed my mind while viewing it is sharing a section for macro and a frag rack.... I have done this before and quickly wished I would have separated the two because the macro just grows too fast to share the zone with frags.

[Gonzobob]

Very good point I hadn't really thought that out.

Thanks Rob

[Gonzobob]

Ok well just about ready to go live with the vat.

Picked up the acrylic from Regal. Had them cut the trapezoid shapes which segregate the return and overflow areas. I also had two rectangles cut which in the refugium area will separate the cryptic zone, macro area and 'live rock and frag grow out' area.

Cut a flow channel and teeth into each of the trapezoids for flow through the macro and 'live rock and frag grow out' areas.

Drilled holes into the blackened piece separating the macro area from the cryptic zone. This will allow water exchange with very little flow.

As I may want to make modifications later and I'm not worried about sealing each section from the other I didn't glue the component parts together. Rather I glued guides to hold the pieces in place.

Holes in the black acrylic allow water exchange without direct flow between macro area and cryptic zone

Cryptic zone showing 'shelves' which will hold up the lid preventing any light into the cryptic area.

Test fitting all the pieces except the lid.

[Jessie]

looking good

[prof]

Have you done a test run with water? Those tubs tend to bow a bit and you may end up with wide gaps on both sides.

[Gonzobob]

Hi Dave and Jessie,

Thanks for looking. I did the test fit without water but did the initial measurements and shaping with the vat filled. The end pieces are fairly tight in the dry tank but I won't be surprised if there's a fair amount of flow around the sides of the two end pieces and have additional acrylic if there is too much.

[stoneroller]

I'd be worried a little about stagnant areas in your cryptic zone, if you aren't actively moving water through there. Sponges need current to prosper. Are you going to circulate water somehow?

[Gonzobob]

While there will be no deliberate current in the cryptic zone there will be water exchange. Originally I was concerned about stagnation but after some research on the subject and comparing notes with some people who have and have had successful cryptic zones it’s something I’ve decided not to worry about it. There will be current supported cryptic activities in the base level of the live rock side of the vat.