DSB in fuge with seagrass...opinions?

[loganj]

I'm thinking about setting up a 40g breeder as a fuge. I want to use a DSB in it and plant it heavily with turtle grass instead of macro algae. I know we have had several threads about DSB's so far and how they may or may not become nutrient sinks as they age. My question is: Do you think the seagrasses, since they actually root in the sandbed, would utilize some or all of these contaminants? I'm not sure what percentage of nutrients the seagrass actually pulls directly from the water column and how much comes through the root system from the substrate. Another thought I had was to put a glass divider in the center of the fuge tank about 4" high. This would facilitate changing 1/2 of the DSB without disturbing the other half. It would seem, if in fact the DSB is going to crash about the 5 year mark, that you could change out 1/2 of it every 2-2 1/2 years and avoid the problems. The side that wasn't disturbed should provide, fairly quickly I think, the needed critters to repopulate the side that had been changed out. Anyone got comments/ideas/theories about this?
BTW, if you feel the need to tell me that this is the most idiotic idea ever conceived and that I should be shot for aquarium heresy, please do it via PM...I can take it 8O .

 

[Dewey]

I think its a great idea but others might have a different thought.



Dewey

 

[scuba_steve]

its my idea that tanks that have crashed after 5 years are due to the lack of adding new ls !! or the lack of the sand being turned !! i really dont think that by splitting the tank in half so ya can change the sand out is the answer !! sand is sand and if there isnt any critters eating stirring up the sand then the new stuff will become a sink as well !! i did like the tank the fellow member had (the L shaped tank) were he had is sand located in tubs out side the tank which he had two where he could take apart and or clean any way he wanted !! mabe thats the better way to do handle such issues !! ya could always dump one tub and add new sand and or just clean real well !! but imo adding worms ect on a yearly basis might be the key that most havnt done and why they crashed !! just my thought


mabe a good test would be setting up a tank fuge style with no fish, deep sand and see how long it takes to crash !! feel that most critters get eaten in main tanks to cause these issues !!

im prob way off but been thinking about this alot lately !!

 

[loganj]

OK, perhaps I need to clarify here. The main tank would not have a DSB. The DSB would be in the refugium. The divider was intended to allow part of the DSB to be removed without disturbing the other half...very similar to having the separate tubs. In addition to all the sand stirring critters, I'm thinking that the seagrass might pull some of the nutrients out of the sand through it's root system. The main tank on this system would have a SSB and LR.

 

[loganj]

Hmm...not too many opinions on this idea. I think, if I set this tank up, I'll try to carefully chart it's progress. Perhaps that will give an idea as to whether it's a viable option or not. I'm going to see if I can find a lab somewhere who can test sand samples for heavy metals and other contaminants. Anyone have suggestions as to what should be tested for? I'm going to guess copper, zinc, and nitrate to start with. If anyone has ideas for other things that might be in a DSB that would cause problems, I'll see if I can add it to the list of things to check. I think the 180 at the Eyecare center, with a 1 year old DSB, might be a good candidate for this. Thoughts?
Also, any input on a method for taking the samples would be appreciated. I was thinking about using a small piece of acrylic pipe to try and get a plug sample that would span from the top of the sandbed to the glass. Again...thoughts?
EDIT: I'm guessing it will be nearly impossible to determine at what depth the impurities occur...not that it matters. My idea is that the sand sample should be packed in RO/DI water to prevent it from outside contamination.
EDIT #2: I have sent emails to a couple of labs to inquire about the cost and availability of the tests. If anyone has already done this and has a link to some results, please let me know. Thanks.

 

[saltcreep1025]

i like the idea... might steal it =)

 

[loganj]

Just don't get caught 8O . Seriously, if you try something like this, I'd be very interested to know how it works out and what your thoughts are. I can hook you up on the seagrass as well...got a place in Florida that collects it.

 

[Guest]

How does the seagrass do (lighting requirements, spreading)? Im getting ready to install a 55 gal fuge, and was going to go with half macron half mangroves. Im in Florida, and can get all the groves, and sea grass I need.

 

[douggiestyle]

I'm thinking that the seagrass might pull some of the nutrients out of the sand through it's root system

i think a good start would be whether or not sea grass removes nutrients through the roots or just uses them as an anchor. as far as i know plants can be fed nutrients through the roots and though leaf feeding (read that on a box of miracle grow) but i am not not sure if this includes all plants.

what are the long term results of mangrove fuges? we know that the leaves of the mangrove are not removing nutrients from the water.

 

[loganj]

How does the seagrass do (lighting requirements, spreading)? Im getting ready to install a 55 gal fuge, and was going to go with half macron half mangroves. Im in Florida, and can get all the groves, and sea grass I need.

I have a few sprigs of turtle grass in one of my coral tanks (20g long). It seems to be doing well under 130w of PC. It hasn't spread or put off runners yet that I can tell. I tried some in the 180g, but something evidently ate it. When I went by there a few days after putting it in the tank, the roots and a couple of chewed up stalks were all that was left...hippo tang is my prime suspect although it could have been the yellow tang I guess. Both of them looked mighty smug.

 

[IMPERATORFAN]

I've been looking into this one as well. Here's a few things to consider from the Florida EPA site:

"Turtle grass (Thalassia testudinum) is the best known, with its large, ribbon-like leaves that are 4-12 mm wide and 10-35 cm long. Two to five leaves per shoot grow from stout rhizomes that may be found as deep as 25 cm in the sediment."

You might want to consider this when setting up your DSB in your fuge. It sounds like they need a lot of space for roots.

Also,

"Sea grasses are extremely efficient at capturing and utilizing nutrients, a major factor in their ability to maintain high productivity in relatively low nutrient environments (Zieman, 1982). They are apparently capable of absorbing nutrients through either their leaves or their roots. Zostera, a sea grass common in somewhat higher latitudes, can take up ammonia and phosphate from the sediments and transport the nutrients to the leaves, where they can be pumped into the surrounding water (McRoy and Barsdate, 1970). If turtle grass has the same capability, it should be of tremendous benefit to epiphytic algae on the sea grass blades, particularly in the nutrient-poor waters associated with coral reefs."

"pumped into the surrounding water ... where they can benefit algae" doesn't sound like what we're after. If this proves to be true, you might want to think a little more about macro's ... even though I have heard several sources (including yourself) talk about how the macro's can suddenly break down. This article does say "If the turtle grass has the same capability", so this may not be the case.

I'm going to keep looking into this one. Let me know if you find anything.

 

[loganj]

You're way ahead of me on the research...I haven't had time to do that yet. This makes me wonder if the fuge should be a combination of grass and a relatively stable macro. I think it's worth investigating. I also want to attempt to get some tests done on sand samples from the DSB in the 180. I contacted a lab today and got some prices...not too bad. I need to get a list together of possible contaminants that should be tested for.