Brown algae, diatoms?

mikeb · 09-04-2004, 11:22 AM

I think that the brown algae I have growing all over my sand bed are diatoms. Actually it's sort of purple. It is spread flat over the sand and thin strands are flowing over it, I can peel it off the sand in large pieces. Is this what diatoms are and should I be worried?

I finally got a digital camera and will try to post a pic.

Lehmann · 09-04-2004, 11:35 AM

Brown Diatom is just that, Diatoms. very small specks of dark brown "dust" that forms on rock surfaces, tank sides, and on sand. The Red slime you are talking about is the next stage of the process of a new tank settling in. Neither the Diatom or the "Purple slime" is actually an algae, but form a Kingdom all of there own. It is beter know as Cyanophyceae! Know you know why they call it slime algae!

mikeb · 09-04-2004, 03:31 PM

Thanks Lehmann. Is this anything to worry about or should I just let it run it's course? Like I said it is pretty easy to take out since it forms a kind of skin on the sand. And you know whats weird, it is really coming in thick in a portion of the tank where I vacuumed the sand, but nowhere else.

JohnO · 09-04-2004, 03:42 PM

Mikeb,

As referenced above it is probably cyanobacteria, which is common in saltwater tanks. The best way of shortening it's cycle is to keep breaking it up with a squirt from turkey baster and/or syphoing it up.

John

mikeb · 09-04-2004, 04:18 PM

Well, I got rid of it. I just picked it right up off of the sand. Really thick, like rubber almost.

Lehmann · 09-04-2004, 08:02 PM

I think JohnO in Melborne has the right idea. It will vanish as the nutrients in the tank are exhausted. Maybe a good idea is to suck it out carefully and NOT return the siphoned water to the tank.

festus · 09-09-2004, 06:12 AM

You will get all sorts of advice about nutrients in the water, breaking it up and siphoning it off etc. All of this is good and is not incorrect.

But..... What temps is your tank running ? What kind of circulation do you have ?

I have just gotten over a bought with the stuff you are describing. I was breaking it up, doing water changes faster than you can imagine just to stay in front. I was convinced it was phosphates in my water etc.

I installed a chiller and brought my temps back down to a civlized range, at the same time I increased circulation.

There is nothing like a slightly under circulated and overheated tank to magnify the presence of nutrients and turn your tank into a greenhouse for the stuff.

Just my $0.02.

Lehmann · 09-09-2004, 07:55 AM

I think that this is perhaps the most likely cause of the problem. I was speaking to an importer the other day and asked him the same question. His reply was to point to two of his tanks. One was a tank pretty much overgrown with algae, very little light and hardly any circulation. The other had a few 2000 lt/ hr power heads that created a virtual vortex in the tank. Along with really good lighting and a temperature of 24C. The tank was spotless and full of corals, hard and soft. His secret was excellent water circulation.

Craig Manoukian · 09-09-2004, 10:06 AM

Diatoms will disappear as the silcate dissapates. Cyanobacteria is an aglea/bacteria that is the best exporter of nitrates and phosphates available and it exists in all tanks.

Circulation and strong lighting, bulbs a year old will tend to be problematic, will greatly eliminate its' environment. Reducing phosphates and nitrates at the source is the best long-range solution, but siphoning off the cyano is the best way to export.

JohnO · 09-09-2004, 11:53 AM

Festus/Lehmann,

Good and vigourous circulation and stablised lower temperatures will certainly help stop an outbreak of cyano :-) The point is however that once you have an outbreak, it's too late. You need to break it up and remove it. Keepong Phosphates and Nitrates down, as Craig stated is also very important, but again as a preventative rather than a cure :-)

John