Brown Algae

[goodfortune]

I'm now 5 days into cycling, and as I came home this evening, I noticed a significant amount of brown algae growing on my LR. A picture of my tank (should) be attached.



I would think it's diatoms, but I have only used RO/DI water to make saltwater, and to replace evaporated water/top-off.

The only "regular" water that has been in my tank was when I filled it to check for leaks and circulation, and the wash water from the southdown sand. I tried to drain as much water as possible out of the Southdown before placing it in my tank.

I've read that algal blooms are a normal part of cycling, but what should I be doing, if anything, to pevent it from taking over? Reduced photoperiod/no lights ( ~9 hr photoperiod now) come to mind. Could the residue of sand wash water and testing water provide enough silicates for diatoms to grow?

As always, all comments, thoughts, and suggestions are most welcome.

"Eyeball" water parameters (dip and read test) are:

NO2-N 0 ppm
NO3-N 20 ppm (I think its reading high)
Alk 120-180 ppm (~160)
pH 8.0 -8.4 ppm (~8.3)

I will confirm by Seachem test kit later

[jesspaul]

I can't tell from the photo but I am sure that diatoms always form a thin film and not any sort of structure. My rock turned a golden brown for a while with the mixture of diatoms and green algae. I would leave it alone or maybe stir it up with a powerhead or a turkey baster. If it will come off siphon or filter it out.

[Stanfill Reef]

Ditto...Siphon off rocks during water changes. Export those nutrients before they make it back into the water column.

[Shaheen]

Theyll go away as the nutrients is skimmed and later filtered by carbon. The best thing to do is absolutely nothing. Keep your hands out as much as possible.

[georgiajams]

Is the brown algae sort of powdery/dustlike, or is it slimey and gooey and forming a film over the rocks?

If the former, then this is nothing to be too concerned about. Do as others suggest. It will probably go away on its own after several weeks.

If it is the slimey stuff, read up on cyano, which comes in a bright red form and a brown snot looking form. This stuff can really be a menace. Try to suck out as much as possible.

[hesstondc]

I have no diatoms...so far.

I have been cycling for about 5 days now as well in the 90. I only have my lights on for 4-5 hours a day though..I would decrease your photo period. You don't need your lights for your tank to cycle IMO. I only have about 15 lbs of live rock in the tank though...Looks like you have more, and My rock was already cycled.

Hope that helps
Clay

[Flipturn88]

I had diatoms when my tank was first setup. They eventually went away on their own, but hair algae replaced them. Then the hair algae receded and gave way to a cyano bloom, which I am currently working on now. Hopefully when this cycle finally finishes the only algae that will grow is corraline.

HTH,
Kayla

[goodfortune]

The algal growth appears powdery, as opposed to slimey. There is also a thin "dusting" of brown growth on the sand bed as well.

As soon as I get my timers in, I will set the tank up on a 4-hr photoperiod, and I will be doing my first WC tomorrow. I imagine that the reduced photoperiod, water change, and the increased flow from the Mag 7 may help matters a bit. As a side note I'm a little concerned that the Mag 7 will create a second "snowstorm" as the pump seems to move qite a bit of water through my tank!

For those of you out there who are experincing brown algal blooms like I am now, check out the Brown Algae FAQ on wetwebmedia

Thanks for your reponses everyone, and keep them coming!