Unknown Clear Substance Growing on LR

[Archietherabbit]

I was hoping someone could help me identify what this clear substance growing on my live rock could be. I first noticed a small amount about 2-3 weeks ago but it has grown substantially since then. The tank has been established for 5 years and I have not added any new organisms in around 6 months. I tested for ammonia, nitrites, nitrates, and pH -all normal. The only change is that there have been some brown diatoms on the glass of the tank, which I presume was caused by having to use tap water in a water change because our RO system was down. So I've been treating with a phosphate/silicate remover.

Whatever this stuff is, it is not easy to rub off. I used a bottle brush to scrub it which basically did nothing. It looks really glowy with the white light reflecting in the picture, but it person it looks more like lines of dried glue, if that makes any sense.

 

[Reefer PT]

Hard to tell from the picture, if it is filamentous like the GHA but in short 1/8' strands it could be chrysophytes which is a silicate based algae that usually is self limiting. Looks like from all the nuisance algae in the picture you need to get your nutrients down. I would suggest carbon dosing as it has worked well for me. Just do a forum search and you will find out more then you ever wanted.
Dave

 

[Archietherabbit]

Thanks for your help, its not filamentous it actually forms a hollow tunnel attached to the LR. It seems almost sponge-like with a really thin wall, but I haven't been able to find any sponge that matches up. This tank is actually a museum exhibit so I like to keep some different algae since it is supposed to representative of natural conditions, although it has gotten a little out of hand lately. This stuff is really spreading though, it's not horribly ugly but I don't want it to start growing on my gorgs or anything since it's basically impossible to scrape off completely. I will try to get a better pic but it is hard since it is so clear.

 

[JPF]

Some weird colonial thing? Like a slime mold on land?

 

[Archietherabbit]

Actually found out it was a type of sponge, I've forgotten the name now...