White fungus?  Not likely...  4/14/07
Hello,
<Hi Jared, Mich here.>
I have a 75 gallon FOWLR and I have some white stuff spreading over some of my rock.
<OK.>
It looks like fungus.  
<A photo would be helpful.  It is highly unlikely that it is a fungus, perhaps a sponge, perhaps just some detritus build up on your LR, difficult to say without a picture.>
If so what can I do to rid my tank of this?  
<I can't say, there is not enough info.  It is possible that this is a beneficial growth.>  
Thanks,
<Welcome, Mich>
Jared

Marine Fungus? 12/8/05
Mr. Fenner & Crew, I'm looking for some information concerning a situation that has recently appeared in my 120g reef tank. Three or four weeks ago, I observed what appeared to be fungal mycelium? emerging from the plenum substrate in my tank. It was growing on the inside of the glass, cream to light green-brown in color and looked like a 'tree' in that it starts as a flat, wider mass at the bottom and meanders upwards and horizontally, branching into smaller and smaller 'limbs' until it terminates in spider web like 'feeder roots'. 
<Hmmm... there are very few marine fungi and no reports that I know of that they make appearances in our tanks.>
The growth is quite rapid as it will cover 25-30% of the side or front glass over night (7-8 hrs.). It only grows when the lights are out and once the tank starts to brighten (daylight & lighting) it begins to degrade and is all but gone by mid afternoon. It happens three to four days in a row and then it may be three or four days until I see it again. 
<Wow! That is rapid growth! Fungi don't need light, but many Cyanobacteria and dinoflagellates do. Based on the rarity of marine fungi and the fact that Cyano and dinos bloom and then wane as you describe makes fungi very unlikely.>
It emerges from different areas in the tank and when it is visible, there seems to be an active layer of the organism about 1-1.5" below the top of the substrate growing horizontally within the substrate.
I have had a reef tank of varying sizes for over 7 hrs (plenum system for 5 yrs.) and have never observed this before. It doesn't seem to have any visible effect on the inhabitants as the SPS, LPS and all of my soft critters are going gangbusters. There are 4 fish (Tomato clown, Sailfin Tang, Purple Dottyback and an Algae Blenny) along with numerous 'cleanup guys' that are all healthy and growing. Water parameters:
Alkalinity: 9-11 dKh
Ca++: 400-420
Nitrates: < 5ppm
pH: 8.2-8.3
Salinity: 1.022-1.023
I haven't checked the phosphate level lately but I don't have any algae problems, so I assume it is low. The tank is set up with a plenum system, 30g refugium sump w/fine sand bed and macroalgae & +/- 130 lbs live rock. I do a 30g water change once/month and vacuum the substrate when I do the water change. I use Mark Weiss products 2-3 times/week and as I said before, the tank is doing great. Except for this 'tree' thing that has appeared. I would greatly appreciate any info or insight you may have and if there is a need for concern? Thanks, Craig Larsen 
<I am semi-stumped. What you describe is most likely Cyano or dinos, but it doesn't sound totally typical of them either. If you would like to get rid of it, I would suggest trying to siphon out as much as you can when it is at it's greatest mass. Usually, with patience, this will eliminate the "stuff" and also accomplishes some nutrient export. You may also consider raising the ORP via ozone. This often helps with Cyano and dinos, and on the off chance that it is fungal, it should help there also (fungi are generally very sensitive to oxidizers). Best Regards. AdamC.>