Cryptic zone vs refugium

[Paalk]

I'm about to add another 350l tank into my existing system. I'm thinking refugium or cryptic zone. What benefits do cryptic zones actually have?

[reefgeezer]

A space where light is very low and flow is just strong enough to keep small particles in suspension is a great place for sponges, tube worms, sea squirts, copepods, and other things to flourish. In theory, organisms like these provide food and bioavailable nutrients to the rest of the system. The substrate they live on (I use rubble rock) provides additional surface area for nitrifying and other beneficial bacteria to grow.

These benefits are not necessarily noticeable in the short term or terribly obvious. To me, it seems like the tank gets better as the Cryptic Zone gets older. IMO, the steady supply of food on the lower end of the food chain makes a cryptic fuge valuable.

[whosurcaddie]

http://reefkeeping.com/joomla/index.php/current-issue/article/140-tank-of-the-month

This guy uses a cryptic zone and explains it very well.

[Timfish]

Well, for starters Steve Tyree, who developed the methodology, is able to grow some pretty fantastic corals without the use of skimmers. I've been fortunate enough to have turkey wing clams succesfully reproduce (albeit only one offspring) is a system with an unlit sump http://reefcentral.com/forums/showthread.php?t=2174608&highlight=clam Problem a friend of mine has with a version of Tyree's Zonal System (skimmerless) is her corals started bleaching from the phosphates dropping too low and she now has to target feed them twice a day.

[o2manyfish]

I think you will get more benefit from a Refugium. Not saying that Cryptic zone isn't effective. I have a variety of sponges growing throughout the caves in my tank. But a Refugium does a great job of nutrient export and providing a food source (pods) for the main display tank.

There is a trend starting that the best coral food source is fish waste. As people start increasing their fish populations and feeding schedules the refugium helps keep the extra biological load in balance.

Dave B

[Paalk]

I like the thought of a cryptic zone as a means to feed corals and it seems to me that this is virtually almost maintenance free. Is this right or am I missing something here?

[reefgeezer]

I like the thought of a cryptic zone as a means to feed corals and it seems to me that this is virtually almost maintenance free. Is this right or am I missing something here?

I believe my dark fuge provides food my SPS and Leather corals. It also maintains a healthy supply of pods that end up in the DT. I don't do anything to it maintenance wise except shine a flashlight in it every once in a while to see what's growing.

My dark fuge, a black acrylic box, is about 18 gallons and has about 35 lbs of rubble rock and 5 lbs of GARF Grunge in it. Flow is from the bottom. It gets about 100 gph normally that is supplied from the sump. If I had more room, I'd love to have a big cryptic fuge that was fed directly from the DT.

[Rybren]

I set up a 20G barrel as an unlit cryptic zone about 3 months ago. It contains about 30 pounds of rubble that is sitting on a raised eggcrate platform. It gets fed from the output of my skimmer at about the mid-tank level. I don't think that the lower level of the barrel gets much flow.

It is too early to tell if the setup is providing any useful benefit. The tank does look better and there is less HA in the DT; however, I cannot state that the improvement is not just caused by the extra water volume and LR. In addition, I added an ATS just before Christmas. It has yet to produce anything other that a brown, slimey algae.

[Paalk]

The only way I can feed that 90 gallon cryptic I am considering is via an overflow from my sump which is situated over the 90 gallon tank. Then I need to install a return pump in there to get the water back into the sump. Would that work?

[Rybren]

I guess that the key questions would be:

a. what happens if the return pump from the cryptic zone fails and everything else continues to run?

b. what happens if the return pump from the cryptic zone continues to run and the other pumps fail?

c. what happens if all of the pumps fail?

If you can sort out what happens in each scenario and then come up with a fail-safe mitigation strategy, then I'd think that you are good to go.

[HiFidelity]

Run both :)

I moved my fuge outside of the stand and placed it next to DT, now my entire sump is a cryptic zone and my fuge works ten times better now that it's a gravity fuge.

[reefgeezer]

The only way I can feed that 90 gallon cryptic I am considering is via an overflow from my sump which is situated over the 90 gallon tank. Then I need to install a return pump in there to get the water back into the sump. Would that work?

Does your sump overflows back into your display tank?

[Paalk]

My sump water is returnere to the DT via a returnpump.

[reefgeezer]

It's not impossible but here's some things to think about and plan for...

What happens if the pump from the cryptic fuge to the sump stops working?

What happens if the return pump to the DT stops working but the one from the cryptic fuge continues to work?

What happens if both pumps stop working?

What happens if the overflow from the sump to the cryptic fuge clogs?

You could also pump water directly from your cryptic fuge to the DT, let it overflow back into the sump via the existing plumbing and then make it overflow back into the cryptic fuge. Balancing and fail safe design for such a system might be harder though.

[Paalk]

Bare with me guys, but isn't the amount of water coming from the DT in an event of return pump failure in either the fuge og sump I should be worried about?
Say if the amount of water from the display is X liters, that will flow into the sump until it stops automatically, right.

Then that X liters is in the sump circulating through the sump and fuge/cryptic so as long as I have enough room in the sump to accomodate that it shouldn't be a problem?

So if the return in the fuge(third level) dies; still the water from the sump will keep overflowing into the fuge until there is no more water over the overflow in the DT, right?
So basically I need enough room in the fuge to cope with all the water from the DT and the water "over" the overflow in the sump....puuuh does that make sense? Hehe hard to explain this but hope you get what I mean.

[Paalk]

One more thing, regarding a potential clogging of the overflow to the fuge. Couldn't I just solve that by raising the return pump in the fuge so that it will stop pumping after a certain level? All I need to do then is making sure that the sump will accomodate that water and the water from the DT in the event of a power failure...make sense?

[jeffkeith_us]

I'm about to add another 350l tank into my existing system. I'm thinking refugium or cryptic zone. What benefits do cryptic zones actually have?

The answer to both questions is unequivocally, yes! Add both a reverse light cycle refugium and a cryptic benthic zone refugium. In the cryptic refugium you'll need an under gravel filter and a powerhead mounted on it in order to suck out sediment each year. Just put a hose on the output of the powerhead and run it for a few minutes.
Don't put any gravel on this under gravel filter, just golf ball size sponge encrusted live rock.
Better yet, contact Steve for a Sponge Kit and Morgan for a Refugium Fauna Starter Kit.

[jeffkeith_us]

"habitats or physical areas that recieve almost no light, and very little water current. In nature they occur underneath or within the base areas of coral thickets, within the numerous cracks and crevices, in the caves and tunnels throughout the reef structure and they occur throughout the twilight zone. The twilight zone is the deep bottom area of a tropical reef platform. Establishing a weak light and weak current zone within a captive container is relatively easy, but to establish a cryptic zone that functions properly the aquarists needs to prevent large particulate matter from entering the zone. Barriers are typically used. Large particulate matter can clog cryptic sponges and cryptic squirts. The cryptic zone does not support photosynthesic animals. Animals that have grown within cryptic environments cannot be placed backed into the exposed zone. Cryptic animals lack an ability to shield themselves from UV light. They can also develop very delicate growth forms that are easily damaged in current. Cryptic zones typically shield or shelter these animals from larger predators. Natural and artificial cryptic zones receive inputs of dissolved organics, very fine particulate matter, bacteria and micro-plankton."
Steve Tyree

Nobody that I know of has ever described a cryptic refugium any better, so scrutinize every words. The Cryptic Zone cannot support 100 gal's.per hour. That would be a semi-exposed zone (also very much needed) refugium.

[lifeoffaith]

I just saw the above tank of the month (shared by whosurcaddie, can't figure out how to quote him) cryptic zone for the first time yesterday. Once I move (a year or two down the road), I plan on setting up a large tank (200+) and was curious how a cryptic zone may be incorporated. I was wondering if an IBC tank could be incorporated into the system (200 gallons once you cut off the top of the tank and cage for it) to use as a cryptic zone. I have one currently that I might just hang onto if I can figure out how to use it. Does anyone here use a cryptic zone that can provide a plumbing diagram? I also thought about using it as a refugium, but I don't think I want to light that large of a tank really. I think it could be a great cryptic zone though, alongside a sump/refugium combo that is a bit more manageable for lighting.

[reefgeezer]

The Cryptic Zone cannot support 100 gal's per hour. That would be a semi-exposed zone (also very much needed) refugium.

I agree that controlling the velocity of the current inside the cryptic zone is important. Some flow is required in order to make a "remote" cryptic zone beneficial to the rest of the system. However, there must be enough input to the zone to provide organics to feed the thing and enough current to carry "stuff" back to the system. Limiting current while supplying enough flow is an important consideration when designing a cryptic zone, particularly when it is remote.

For example: In my system, the water from the sump enters the zone via a stand pipe that routes it to the bottom. The stand pipe has three outlet tubes. The water overflows back into the sump. The area inside the zone is roughly 18" X 18" X 16", so 22 gallons max. Considering the amount of rock I packed into the thing, the actual water volume is much, much less. I run about 100 gallons per hour through the zone. I figure the actual turnover is at least 5 to 6 times per hour. At that rate there is no appreciable current inside the zone and it appears healthy. In addition, I have sponges and other critters growing in the sump so I'm pretty sure "stuff" is being returned to the system.

[tmz]

I've run my unlit "cryptic" areas for over 6 years.
A 32 gallon lidded unlit brute garbage can filled with large pieces of live rock receives about 300gph of water from one of the drains in the system The drain water enters the can at the bottom via a pvc pipe through the lid ; the water exits from a bulkhead with pvc on the side of the can near the top. So, it flows upward through the rocks. It flows from there into a bin in ambient light which contains a 7 inch deep sand bed covered with live rock chunks and then into the sump for skimming and redistribution to the display tanks . All gravity fed; no pumps. Easy to maintain. Lots of sponges filter feeders and pods are evident throughout the system.

I also dose organic carbon ,so the extra surface area for heterotrophic bacteria to colonize seems to be a plus since there are no visible globs/strands of bacteria in the rest of the system as often occurs with organic carbon dosing. I think the extra bacteria also help the food web.