Base Rock causing problems?

About a year ago I put some base rock in my aquarium; about 50 pounds. I gave them a huge rinsing, and added them to my display with the other 200 pounds of LR I already had in my system. Shortly after I started having a weird type of algae, purple mossy type. Not coralline algae, that I already had a lot of. Anyways, I have been battling it since. Is it possible that my baserock wasn't washed properly and is feeding this algae? I did a few test in the water but of course its coming up empty since whatever is fueling the algae is being sucked up my this purple moss.

I'm weary about removing the rock because they are HUGE pieces and quite cavernous. I have a ton of bristleworms and snails hiding out in there with other CUC compatriots.

 

What type of rock is it? Is the algae only on the rocks in question?

 

Sounds like it might be cyano from your description. The rock could be leaching phosphates.

 

I honestly have no clue what type of rock it is. I asked the LFS and they just say 'base rock.' And yes, the LR doesn't have any on them. They did at one point (the tank was covered) but I beat it back successfully by starving the tank of light (reduced photoperiod times from 12 hours to 6 over 7 months and only turned on my blue LEDs). However this purple turf like algae is still present on the former baserock.

And in terms of Cyano, I would be surprized. I never had cyano problems, and this purple algae is furry and impossible to remove from the rockwork. I've tried searching but can't find this stuff anywhere. I'm pretty sure I've managed to breed a new string of super algae lol

 

Kind of sounds like what is commanly called red turf algae. Grows real short, wont scrape off, has a texture like nylon strings. Does that sound like what you have?

 

Yes actually that's exactly what it sounds like. Odd that it's primarily on Base rock though

 

Can't say why its limited to that rock. I have found that large Turbos (Mexican Turbos) and Urchins will eat it. Add a couple and give them time they will keep it in check, although I doubt if it ever gets truly irradicated

 

Ah ok. A shame that it'll never truely be gone. Although like I said it was completely covering my rocks at one point so to have it limited to just two rocks is a semi-victory. I might just remove them and buy some new live rock. Get some new bacteria in there to mix things up a bit.