Live rock question

[reefin]

I see there is more and more live rock on kijiji coming up for sale!

Is there such thing as live rock being too old?

How much bad does it absorb and how can you really tell what is good or bad and what will it do going through a new cycle?

I want to buy for my sump an DT but I'm a little skidish about something that was in a tank for say 5 or 8 or 10 years.

opinion?

 

[Krazykarl]

If it comes from an existing system that is up and running you should be able to tell the condition of the rock based on the tanks appearance. If it has green hair algae or any algae you can guarantee there will be po4 in the rock. It does absorb nutrients. If the tank is 5,8 or 10 years old I'd take that over rock that is recently put into a system. By then it's safe to say its established. All you are looking for in the way of "live rock" is the necessary bacteria for biological filtration. A means of breaking down ammonia. Personally I wouldn't bother adding any rock to a sump. In my 3 yrs doing this I've only found it to be a problem as it does nothing but cause build up and create nitrates for me. I run a empty sump with equipment. That's it. Well, right now I don't bc I emptied out my DT a bit and rescaped it. But usually lol, I have no rock. That just my opinion. I'm sure others on here will disagree. It's whatever works for you.