Fake live rock is being mauled

[iamahab]

Hey fish nerds, I have a ton of fake purple live rock I bought when I first started keeping saltwater fish. I was new to the game so I ended up getting 20 lbs of purple plaster rock. It works and looked good until I bought a pincushion urchin. He/she is now slowly scraping the purple off of the rock exposing parts of the plaster. I would like to fix this by getting some real live rock but i'm unsure how to go about it. I know I can't just pull the rock out and replace it with real live rock. Should I replace a piece at a time and see where it goes? What kind of issues should I expect?

 

[lapin]

With a normal bio-load I would replace no more than 10% at a week with dry rock . 10 weeks and your done.
Live rock I would go 25% . Not being sure how much and of what bacteria type is in it.

 

[iamahab]

With a normal bio-load I would replace no more than 10% at a week with dry rock . 10 weeks and your done.
Live rock I would go 25% . Not being sure how much and of what bacteria type is in it.

thank you

 

[Naturalreef]

If you have it already seeded, why mess with the bacteria balance? Imo, a healthy reef tank will seed all those spots with real coralline algae if it comes on a frag or you seed it from someones tank. Just my opinion….

 

[Tonycass12]

Don't even stress about it. That stuff chips off the smoother parts of the rock within a year anyways. It will all get re coated with coralline eventually. FYI urchins eat coralline as well as other algae so this will still periodically happen in the future so long as your keeping urchins you will always find "bare spots"

 

[coralfishreef]

Urchins scrape rocks like you’re seeing. With an urchin and a small tank, the rocks might always look freshly scraped. Once the corals grow in it isn’t so noticeable.

 

[Porpoise Hork]

Pincushins are absolute beasts when it comes to eating algae. They will scour the rock so it is devoid of ANY type of algae including coraline. They also have a nasty tendency to yank frags out of the rockwork and carry them around like a hat. Had one that loved to do this with my zoa frags.

 

[iamahab]

Don't even stress about it. That stuff chips off the smoother parts of the rock within a year anyways. It will all get re coated with coralline eventually. FYI urchins eat coralline as well as other algae so this will still periodically happen in the future so long as your keeping urchins you will always find "bare spots"

Knowing what I know now about live rock/dry rock I'd eventually like to make the switch to real live rock and not this plaster crap. I can live with it now but I'd like to make the switch

 

[G Santana]

Just realize that you will have the same issue with live rock, urchins will scrape that as well.
I don't know what the composition of that fake rock is, but I would replace it in stages.

Good luck

 

[iamahab]

Pincushins are absolute beasts when it comes to eating algae. They will scour the rock so it is devoid of ANY type of algae including coraline. They also have a nasty tendency to yank frags out of the rockwork and carry them around like a hat. Had one that loved to do this with my zoa frags.

Yeah the urchin has worn a few of my frag plugs. I think it was trying to trick my clowns" i'm a zoa frag now". It's currently wearing a few loose matrix pebbles as a disguise.

 

[Timfish]

I'd add some maricultured live rock or wild live rock just to get sponges and micribial stuff (only a couple percent of the microbial stuff can be cultured and stuck in a bottle). As mentioned above urchibs will scrap rock bare irregardles of what type it is. So the question is how much efgort do you want to put into switching it out. The above mentioned 25% seems a reasonable number ti me but your easthetics and time are the real judge.