Hello, newer tank, first encounter of growth and hoping it is good!?!

Hello, I Have recently set up my first attempt at a saltwater tank and am now experiencing the fist growth or change in the tank and I am curious to what it may be and if it is harmful or not. Here is a pic:

My tank's parameters are as follows: 75 Gallon, 80 lbs live sand, 4 buckets of dead rock seeded with about 15 lbs of live rock. I have one clown, you can tell from the pic he is a curious one. I came home tonight from being away the weekend. I had my brother feed the clown ( Mysis shrimp if it matters) and run my lights for about 6 hrs today, he forgot on Saturday about the lights. the new live rock is the dark purple ones in the pic. when I got home tonight I noticed some brown spots on the rock. it is only on the live rock I seeded with, I do not see it on sand or dead rock, also my protein skimmer has started producing some liquid, first time I had to empty it so far. my levels are:

Ammonia= 0
Nitrite seems about between 0 and .5 but the water is almost perfectly clear, so I am leaning closer to the 0.
Nitrate looks to be about 10
alkalinity around 200
ph about 8

I searched the forums a bit and brown algae seems to be a popular verdict but the pictures posted don't seem to match exactly. I am mostly curious and looking forward to what I hope are many surprises, hopefully good ones, from this tank. is it something to fix, to leave? does it mean the cycling is about over? does it mean I should invest in a proper clean up crew? thanks for the input, you guys are amazing. -Anthony

also, I did use RO/DI water, seems like a popular question when someone asks about algae.

It's most likely diatoms.

Also your picture didn't work.

Here is a retry to add the pic.

I'm sticking with diatoms.

Is there any action that I should do? like water changes or lighting changes? I assume i am nearing the end of the cycle based on the tests. i have heard that after the brown, then i get green? is this true?

Diatoms use silicates to build their shells. When the silicates are gone, the diatoms will die off. They're ugly, but harmless.

will they harm or kill the coraline under them on the rock?

Nope.

ErinCahir said:

Nope.

Click to expand...

+1
if you're really concerned about it run some phosguard thorough a media bag.

I have your same problem right now. Good luck with your tank and I believe this is one of the multiple experiences we are not going to enjoy in the hobby.

Hello, after I encountered this problem, I stopped running the light because I did not have any corals or clean up crew. Now that I have a coral, I started running the lights again and the brown stuff has gotten worse, If it is diatoms, then I am fine waiting for it to run its course, but today I noticed like a little tuft of brown hairy stuff. its circled (faintly in red sorry) :frustrat: in this picture. it is attached to the rock on one end and sways with the current.

I do have a bit of a phosphate issue, which I am fighting with GFO, a phosphate mat, and the pulsing xenia coral I have supposedly likes the phosphates? I have been running the lights about 6 hours a day right now. Should I let it be, or change lighting schedule? Should I add something to my cleaning crew( I only have 10 Nassarius Snails currently)? I do have a water change coming up tonight also. Here are two other pics of what I think are probably still just diatoms. On the first one you can see where one of my nassarius snails started cleaning the rocks


Thanks, let me know what you think.

Also, there seems to be none on the sand, but I did have some on the glass today also.

Looks like cyano too me in the first two the last pic is diatoms.

I believe it may look like that because the first two pics show rocks that were the live rock I seeded my dead rock with. They have purple coraline on them with brown over it. There is a spot in the second picture where a snail cleaned off part of the brown and you can see the purple. The third picture is one of the dead rocks that was white, which might show the diatoms, if that's what they are better. Any other opinions?

Still looks like cyano in the first two.

Whatever it is some Astrea (12) and Turbo (2) snails have been feasting on it for the last 2 days and have it almost under control.

That's great.

Cyano can be toxic to snails.... keep an eye on them. Toss any if you see deaths as it will only feed the cyano.

Cyano was a really big battle for me. As you have mentioned, a GFO was the only thing that sorted it. Personally, I run a phosban 150 with about 75g of CFO that gets replaced every 3-4 months. Phosban will take 3-4 weeks until it shows an effect on your tank. After the initial algae kill, change your media as it's likely consumed already. Leave the changed media until you see the first sign of the algae coming back; thats your que to change the gfo again.

10 snails in a 75 gallon are not going to cut it. check out www.reefcleaners.org. This guy comes highly recommended by just about everyone. I can't tell you how many clean up crews and top-off's I have gotten from the man.

I have had a few cyano battles over the years and this works for me every time: Give it a Red Slime treatment, skimmer off for 3 days, massive water change after 48 hours, vacuum the cyano out during the water change, done. When you turn the skimmer back on just watch for extreme collection cup messes. I've done this with corals, inverts, fish, with no problems.