Fertilizer for sand bed

[ozadars]

Hi there,
I used a freshwater tablet fertilizer for my sand bed before. I dont know if it worked but they are hard to find and expensive. I dug it into my sand bed.

A local freshwater planted tank keeper is selling a powder fertilizer. I think you mix it with water in a box and add it to your tank. Would this fertilizer be unsuitable for use in saltwater? Its contents are; 7% Fe, 1.3% B, 2% Mn, 0.06% Mo, 0.4% Zn, 0.1% Cu, EDTA, DTPA..

Thanks.

 

[SeanT]

What possible reason would you want to add fertilizer to your tank for?!?

 

[Samala]

Hi Selim!

Looks like that powder is just micronutrients, or trace nutrients, aimed at terrestrial plants. Its close to the trace mix from Seachem I've been using - the contents for that are similar, but the amounts are very much off. I would be especially cautious about the copper, but all of the elements are in higher percentages than in the mix I use. Which I should think would mean you should use a lot less of it.

Seachem trace mix
Zinc 0.017%
Manganese 0.009%
Copper 0.003%
Boron 0.003%
Molybdenum 0.0003%
And incredibly tiny amounts of
Cobalt, Rubidium, Tin and Vanadium

The fact that this includes iron is another thing to consider. Iron in high doses can be toxic in saltwater.. I dont know at what concentrations exactly. But you do need some in the tank. I have a feeling that if you dose the iron with this mix at the right rate, the other trace nutrients will be too high.

So.. maybe what I would do.. since these things are hard to come by over your way.. is to get ahold of a little bit of this stuff.. and use it only to supply trace elements to the tank. Get a seperate source for adding iron if you want to play around with that. If you are going to rely on the bioload of the tank for N and P I think you're set otherwise.

Did you have any luck finding fertilizer tabs for the sandbed?

I wonder if you had access to agar, if you could blend up the traces, gel them with agar, and make your own little trace element pellets for the sandbed. I might try that myself.

>Sarah

 

[SeanT]

What possible reason would you want to add fertilizer to your tank for?!?

 

[Samala]

Hi Sean - if you look down this board you will find many many references to adding fertilizers to tanks that have a medium to low bioload and a high load of macroalgae or seagrass. We are playing around with models of how nutrient dynamics play out in tanks that 'specialize' with lots of algae and plant life. I know Ozadars is planning a lovely seagrass tank with Mediterranean species, so I'm pretty excited to see it all come together.

>Sarah

 

[piercho]

One thing a few of us have dosed consistently is iron chelate. Before I moved the tank and still had the algae scrubber going, I tried to get some iron in every day. I think that billsreef also uses it in his seagrass tanks. The only other liquid additives I've used have been limewater and acetic acid. I have tried Seachem fertilizer substrate tabs right by the roots of grass transplants. Don't know if they helped, but they didn't seem to add any fuel for undesirable alga in the rest of the tank.

My opinion is that iron tends to be limited. I dosed small amounts daily for that reason, and I think that RH Farley on the Chemistry Forum does something similar for the same reason. On the other hand, there is speculation that a introduction of iron to the system can lead to coral bleaching. An example of where this might have happened is when someone starts using granular ferrous oxide as a P-fixer.

All that said, my objectives are probably different from yours. My grass has to eek out an existance mostly on what it can pull from the bed. Sarah is the one who has been aggressive with additions of both major and minor nutrients. I'd be prone to following her advise if quick growth of grasses is your goal, as most grasses have been slow to get going in my tank.

 

[ozadars]

I dont know if adding iron would bleach corals but also can lead them to brown maybe. Iron in the water can cause Zoanthellae (sp?) to over populate in/on the coral and over population of this micro algae usually helps corals to grow quickly but also loose color and get brown. Just a teory, I havent experienced it.