Brown algae? Diatoms? Dinoflagellates?

[mhsmith]

I am reaching out for help. I have had a brown growth that appears on my sand and on a few rocks. I have vacuumed the sand and it improves but comes back each time. My tank has been up and running for 1.5 years, but the rocks i used were from a previous tank. Things look good in the tank with the exception of the ?brown algae that forms on the sand and glass. When I scrape it off the glass the tangs eat it. My parameters are phosphate-0.00, nitrite-0.004, calcium 415, and alk-139ppm. Salinity is 1.025.

 

[mhsmith]

These are photos

 

[mhsmith]

This may be a better photo

 

[bertoni]

It's hard to tell from the pictures. Diatoms have a hard shell, and don't form a gel the way that dinoflagellates will. Also, a number of snail species, including Trochus, will eat diatoms. Getting something to eat dinoflagellates can be harder. I don't know that the tangs are very picky. I never kept a tang.

 

[Michael Hoaster]

Looks like diatoms to me. Does not look to be putting out bubbles, like dinos do. Fighting Conches are good sand bed cleaners.

 

[bertoni]

If they are diatoms, then snails should eat them. You could consider trying a silicate test, but they tend to be indeterminate. Diatoms require a bit of silica to create their tests (shells), but they don't need much, so that's hard to control.

 

[bozoreefer]

Could it be that his redfield ratio is off?

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[mhsmith]

what do you mean by redfield ratio? I don't know what that is. I was reluctant when I got the new tank to get a huge clean up crew, but that is probably a good idea. Any suggestions as to where to purchase. In the past I used reef cleaners, but they sent a lot of tiny snail and I am not sure how functional they were.

 

[Michael Hoaster]

The Redfield Ratio refers to the ratio of macro nutrients (Carbon/Nitrogen/Phosphorus) used by phytoplankton, which corals consume. Hitting that ratio (106:16:1), is the goal of some reefers.

An ideal clean up crew isn't huge, but starts out small, then reproduces to the numbers needed to match algae growth. Reproducing snails fit the bill. Check out Cerith and Mini Strombus snails, which will reproduce for you.

 

[mhsmith]

how would you measure that ratio? Do you have a suggested vendor for the clean up crew?

 

[Michael Hoaster]

You would test your water for CO2, total Nitrogen, and phosphate (I think).

I like Gulf Coast Ecosystems (live-plants.com) and Indo-Pacific Sea Farms (ipsf.com).

 

[mhsmith]

hey thanks for information. I will try above

 

[Michael Hoaster]

My pleasure, cheers!

 

[bertoni]

The Redfield Ratio doesn't mean anything in our tanks. I would concentrate on adding a few snails to eat the diatoms. I have had good experiences with ipsa.com, as well. A local fish store might have some cerith snails available, though.

 

[bozoreefer]

The Redfield Ratio doesn't mean anything in our tanks. I would concentrate on adding a few snails to eat the diatoms. I have had good experiences with ipsa.com, as well. A local fish store might have some cerith snails available, though.

The n p balance is irrelevant in our tanks?


I see people dosing no3 or po4 depending on what they lack just so they can diminish cyano

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[bertoni]

The Redfield Ratio is for phytoplankton, which isn't what we are growing in our systems.

If a tank lacks phosphate, for example, adding some might help organisms consume nitrate, but I am skeptical that any specific ratio is useful.

 

[coralcruze2020]

looks like brown cyano backteria...