Marty Boeckman:

I concur with the above with 1 exception. Seagrass needs alot of iron. Both Bill Capman and I have noticed significant declines in our seagrass when not dosing iron.

Mike Kirda:

What do you use for iron dosing? I'm half-thinking of adding some to my sump...

Bill Capman:

What Marty and I have both found is that when we use Biotrace (which is supposedly high in iron) regularly our turtle grass does well, but if we stop for awhile the turtle grass stops growing and starts to fall apart. Resumption of Biotrace use results in a noticeable improvement quite quickly (I'm remembering something like within a week or so).

I have seen this happen several times (at least 3 times), though I have not done any good controlled experiments to tell me that this is definitely the factor responsible for the variation in turtle grass growth. A number of years ago before I started using Biotrace I also felt that iron supplements (one of the liquid ones...I think I had the Kent brand at the time) gave a similar response. This was all sort of anecdotal, and still is really, but just recently Marty had the experience of running out of Biotrace and found his turtle grass declined in health as well. I'm starting to have greater and greater confidence that this effect is real. I think we are still sort of guessing that iron is what is responsible, but I really suspect it is, and it makes sense.

Shane Graber:

Have you ever considered placing a clay ball of laterite clay underneath the root structure of your seagrasses? Considering that seagrasses in general are vascular plants, they might actually do better uptaking iron from their roots than from the water column. I'm drawing from my limited knowledge of freshwater planted aquaria on this one. Some fw plants are better at uptaking Fe from the water column and others are more apt to uptake Fe from the roots.

Bill Capman:

This is an interesting idea that had crossed my mind in the past, and it might work well. My only concern is that if the sandbed were to get disturbed at a later date, this might result in a whole lot of iron (not to mention clay) being liberated into the system all at once, and I don't know what the consequences of that would be for the system overall. With the regular Biotrace additions things are a bit more controlled.

Michael Raffa:

I believe Shane has really good idea here...Instead of a ball laterite clay, why not create a layer of laterite, say 1" deep on the very bottom of a 4-5" DSB. How far would the roots go on Turtle Grass? Would they seek the laterite or would the iron seep through the DSB and feed the grass that way?  

Marty Boeckman:

I have tried just using a regular iron supplement, but that doesn't work as well as InlandSea BioTrace. Biotrace is like Combisan but with more iron. It's what Morgan at Inland Aquatics recommends. He has found that particular product to work the best. And from an anecdotal standpoint, I agree with him. It's pricey, but I plan on buying it again.

The system I have the seagrass in is a 58 with a 30 gallon sump. I added 5ml of Biotrace each day and the seagrass was spreading very nicely. I ran out of Biotrace, and bought a Kent iron supplement and Kent's Combisan equivlent called CoralVite. I am dosing small amounts of these each day, and the seagrass is dying back (It could be that I should have known better to buy Kent products given that Bingman doesn't think that highly of them :) ).

Inland Aquatics is the only only place that I can find that sells Biotrace. I take that back, I just found http://www.marineandreef.com/shoppro/trace_elements.html

Shane Graber:

Any idea what's in BioTrace besides high levels of iron?

Marty Boeckman:

It's the multisupplement similar to Combisan. As I mentioned before, I ran out a while back, so I don't have a label to read. But I do recall that Biotrace had a higher vitamin content than it's competitors. When I get some more, I can post the label contents. Or if someone on this list has some, please post them.

Biotrace isn't some magic potion that will transform your tank into something marvelous. My 180 is a beautiful tank and I don't dose anything. I just wanted to emphasize that so people don't think they have to go out and buy it. I use it because its works great for seagrass.

Shane Graber:

I just happened to be doing a search for Biotrace and came up with a post from Bill on ReefCentral on 09/23/2001 ( http://www.reefcentral.com/vbulletin/showthread.php?threadid=31334 ):

QUOTE: "I have have had turtlegrass growing well for 3 or 4 years in an ATS-filtered reef/seagrass multitank system (photos and info can be found at http://www.augsburg.edu/biology/aquaria ). It is growing in fine oolitic sand (about 4" deep) with no other supplements to the sand bed. The system is very heavily fed. I often use a trace element supplement (Biotrace), but on several occassions I have slacked off and not added it for weeks or months at a stretch. Each time I have stopped the Biotrace additions I find the turtle grass starts to get pale, growth slows or stops, and the plants start to fall apart. When I then start the biotrace additions again the turtle grass starts looking much better within a week or two. I have not done controlled studies to verify that it is really the Biotrace and not something else that is responsible for the recovery, but I have seen the above patterns of decline and recovery several times now.

 

My *suspicion* has been that iron is what is responsible for the improved growth (and I'm told that Biotrace is quite high in iron...actually I now have ICP data for Biotrace so I should be able to tell how much iron is in there for sure but have not yet gotten around to looking at the data from this perspective), but again I've not done any good controlled studies to verify that iron supplementation (rather than some other element) is what the turtlegrass is needing.

 

p.s. After being given some new fish recently that were housed temporarily in my seagrass tank, I now know that both foxface rabbitfish and purple tangs are avid turtlegrass eaters....I had one of each of these species in my seagrass tank for a month and a half or so, and after being in the tank for two weeks all of my turtle grass was mowed down to short stubs! The offending fish are out of the tank now though, and the turtle grass is starting to grow back from the very substantial rhizomes under the sand."

Bill, have you had a chance to look at that ICP data for Biotrace that you had ran last fall?

Bill Capman:

No...this is one of those things that is on my long "need to get around to doing sometime soon" list.

My experience is that turtle grass takes a while to get established. It develops very substantial tough, thick rhizomes and root systems, and biomass below the sediment typically exceeds "aboveground" biomass in established stands. If your turtle grass is healthy and growing well otherwise, I think it is just a matter of time before it starts to spread. This might take 6 months or more though, depending on whether or not the shoots you started with had intact rhizomes. Once established, it can spread fairly rapidly (but don't expect it to carpet your tank anywhere near as fast as the superficially similar looking Valisneria can in a freshwater tank).

Incidentally, circumstantial evidence (NOT controlled studies) in my system suggest that turtle grass growing in aquaria (or in my system anyway) really benefits from trace element additions. My suspicion is that iron might be what is important. My turtle grass did not grow well for me (in fact, it was slowly dying off) until I started using Biotrace (a trace element solution recommended by Inland Aquatics to enhance the performance of their algal turf scrubbers...Biotrace supposedly has quite a bit of iron in it). On two occasions over the past few years I stopped using this and all other trace element additives completely for a few months. In both cases, the turtle grass became pale, growth slowed greatly, and some dieoff started to occur. Within a few weeks of resuming Biotrace additions, the turtlegrass color improved, and growth went back to normal.

Also, my observations from growing turtle grass over the past few years lead me to believe that it needs a LOT of light. Mine is directly under a 400w 5500K metal halide. Though it is growing well, the blades are narrower than much of the wild turtle grass I have seen, and it is a good deal taller than any wild turtle grass I have seen, suggesting that it is a bit etiolated.