Algae in new tank


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Hey all,

I'm a newbie and I am looking for a little reassurance.

I have a 29 gallon biocube that is about 2 weeks old. It has 20 pounds of live rock and about 40 pounds of live (AgroLive) sand. It cycled so quickly that I never even saw any ammonia or nitrites. The nitrates had climbed to about 20 a couple of days ago so I did a 5 gallon water change. Saltwater was bought from a LFS.

I have 6 astrea snails and 12 hermits in as a cleaner crew.

Just before the water change I noticed a little rust colored algae starting to grow on the rock. Now, two days later, the algae (I'm assuming its algae) covers about half of the sand and rock.

I have read about these algae blooms, but it is disconcerting to a newbie to watch this happen.

Should I be doing anything, or will it just take care of itself?

Happens to all of us... it is called life :)

after it calms down.... skim, keep alk and calc up and it should burn it self out.

Bad light or direct sun will screw everything I just said :(


hope this helps...
Welcome to ARC.

Best if you use your own salt mix.
If you can then get an ro/di Unit. It will save you money in the long run and you know forsure that your watter are clean rather then trusted someone else water.
Welcome to ARC!!

Sounds like a diatom bloom which is apart of the cycle. Does it look like a light dusting all over the place? If so, don't worry, it will go away.
I think you can trust the water from the LFS. However, it will be cheaper in the long run if you mix your own water.
I think you can trust the water from a few fish stores, but certainly not all of them.

Many don't change the filters when they need to be changed, and some don't mix the salt to 1.025 to save money.
if your tank is only two weeks in and you didnt see an ammonia spike then your cycle probably hasnt even spiked.

The brown-rust algae is a diatom bloom... completely normal and will go away in about two weeks. Just keep cleaning it off the glass and let it take its course.
The saltwater was bought at Marine Reef. They seem to run a pretty good shop, and I would expect their water to be OK, but I have not tested it.

At 5$ per water change, it would take many water changes for a RO/DI unit to pay for itself with such a small tank. It is something I would like to do in the long run, but with all the other expenses involved in establishing a new tank I decided this one could wait.

The tank is not in direct sunlight, so I am hoping that this will pass.

I am interested in tscia's comment that if I didn't see any ammonia than the cycle has not spiked. If that was the case, how does one explain the level of nitrates that I was seeing?

Thanks for the advice.

What are you using for topoff?

fyi don't use salt watter. I myself had done it and so are some other people I knew. Big mistake :D
I have had a problem buying RO water from a LFS, so I also urge caution. If you have a TDS meter test their fresh water. It should be 1 or less ppm. If you don't have a meter, ask them to test it and show you when you purchase. I had a bad algae outbreak and found that the LFS RO water was at 13 ppm (my home is 40 ppm). That is when I bought my own RO unit.
you can still have a cycle without seeing a mojor spike in ammonia. The ammonia is undoubtedly there, just not in very high levels. If you're seeing nirtrates, it has be be coming from somewhere (lower levels of amm). Some people force a high spike by adding a piece of raw shrimp from the grocery store. One thing I can be certian of is that your tank IS cycling. Without a mojor spike, it's just going to take longer.
IMO, I would hold off on doing waterchanges until you see the nitrates and nitrites drop to zero (and ofcourse, do not add any livestock!)

The diatom bloom is evidence that there is a cycle... its completely normal to see it within the first 10-15days and will last for about the same time until it runs its course.

Just try to be patient and listent to what the others on the board have to share in their experiences.

oh and btw, I forgot to say....

:welcome: WELCOME TO THE
I hate leaving post like this... I usually get hammered...

I have 4 tanks, so... a RO unit is a necessity. I have a 24 GPD unit (actually makes about a third of that) But you have a 29 gallon tank. you are only going to need a couple of gallons per week.

I've kept small tanks over the years and used nothing more that a Brita pitcher filter. These tanks were generally FOWLR or they had a few softies (polyps and shrooms). But it worked great. They are about 15 bucks at publix...

Some hardliners will scoff at this... but it worked for me.

Keep in mind... over the years.... this is not the cheapest way to go! but it does work pretty well and it doesn't cost much to get started.
"Some hardliners will scoff at this... but it worked for me."

I think I would buy a de-i canister before I tried using a Britta filter...... before I got my ro/ I used my under the sink carbon filter(pretty nice $150 unit) . and I still had phosphate issues and excessive algea.
You can buy a de-i unit for about $40 and you will be much happier with the results.