Kongar
Active Member
Hi all,
I thought I'd document my journey changing out 100% of my live rock on an established mature tank (2yrs, 9mo old). I looked for threads on this and while I got a few hits - they weren't conclusive and sometimes contradictory (welcome to the hobby). Let's start at the beginning - my rocks were too high, leptastrea and mushrooms had invaded, corals were too crowded and killing each other, and it was a poor use of space in general for a small tank. Here's what it looked like before:
Of primary concern was the fact that it was a bare bottom tank, and what would happen if I pulled all the live rock and replaced it? Would I be at risk of an ammonia spike? I could have rigged up a bucket and some pumps and cured the rock, but it's a really small tank. I decided to take the risk and just replace it.
I did a couple of things: 1) I stopped scraping the glass for a few weeks and let it get funky. 2) I left a good chunk of filter floss in the media basket and didn't change it for a week. 3) I mixed up a bunch of salt water in case of emergency - enough for two full 100% water changes. Short version: no spikes. Ammonia, Nitrite, Nitrate wise - the tank operated without skipping a beat. Here's what it looked like right after the change:
Under whites:
So cycling wise - nothing to worry about. However, within three days - I had kicked off an entirely new ugly phase cycle. It was as if the tank had just been set up. No diatoms - interesting - I expcted them to show up for a hot minute. Instead, first came the dinos - (I've struggled with dinos in the past - but I haven't seen them in over a year now). To be honest, I was a little dismayed at first.
Yes it's dinos. Same ones I struggled with way back when. I believe a combination of prorocentrum and SA. I scoped them. It got snotty, strings and bubbles and all. I kind of wondered the effects of removing all the nooks and crannies of the live rock - I think this is the answer - I maintained my bacterial populations on the tank walls and back chambers, but lost probably all of my micro crustaceans. So I tossed in a jar of pods and let it ride. I didn't even clean it off the rocks - took a 100% hands off approach. No change in lights.
Flash forward a week, the dinos are subsiding. I'd say they are reduced 75% from their peak and the snot strings are gone. In their place, cyano is now breaking out. One spot pretty bad near a monti setosa, but also little spots breaking out all over the tank - mostly where the dinos have disappeared the most. Interesting development since I've never once had cyano in this tank.
Full shot 2 weeks since the rock work replacement:
Biggest Cyano patch:
Dinos receding - comparison shot: (you can see the little red/purple cyano spots breaking out to the right of the base of the torch)
TLDR: it seems that in a mature tank, it's pretty hard to kick off a new nitrogen cycle. There's enough bacteria around on the walls and sump/back chambers to keep things working normal. What does happen though is a new ugly phase, and the major disturbance will bring back old problems and tank imbalances. However, being a mature tank - it seems to work through these phases rather quickly. Tank "rematured" in two weeks what took months prior.
I'll update this thread weekly and I'll document the results. Feel free to ask questions or hijack the thread with your own results. It's all in an effort at sharing information and learning (and this topic isn't well covered IMO). The safest bet is probably to cure the rock in the sump, and replace pieces of it over time. But for those of us with nanos and no sump, sometimes your options are limited.
Thanks
Kongar
I thought I'd document my journey changing out 100% of my live rock on an established mature tank (2yrs, 9mo old). I looked for threads on this and while I got a few hits - they weren't conclusive and sometimes contradictory (welcome to the hobby). Let's start at the beginning - my rocks were too high, leptastrea and mushrooms had invaded, corals were too crowded and killing each other, and it was a poor use of space in general for a small tank. Here's what it looked like before:
Of primary concern was the fact that it was a bare bottom tank, and what would happen if I pulled all the live rock and replaced it? Would I be at risk of an ammonia spike? I could have rigged up a bucket and some pumps and cured the rock, but it's a really small tank. I decided to take the risk and just replace it.
I did a couple of things: 1) I stopped scraping the glass for a few weeks and let it get funky. 2) I left a good chunk of filter floss in the media basket and didn't change it for a week. 3) I mixed up a bunch of salt water in case of emergency - enough for two full 100% water changes. Short version: no spikes. Ammonia, Nitrite, Nitrate wise - the tank operated without skipping a beat. Here's what it looked like right after the change:
Under whites:
So cycling wise - nothing to worry about. However, within three days - I had kicked off an entirely new ugly phase cycle. It was as if the tank had just been set up. No diatoms - interesting - I expcted them to show up for a hot minute. Instead, first came the dinos - (I've struggled with dinos in the past - but I haven't seen them in over a year now). To be honest, I was a little dismayed at first.
Yes it's dinos. Same ones I struggled with way back when. I believe a combination of prorocentrum and SA. I scoped them. It got snotty, strings and bubbles and all. I kind of wondered the effects of removing all the nooks and crannies of the live rock - I think this is the answer - I maintained my bacterial populations on the tank walls and back chambers, but lost probably all of my micro crustaceans. So I tossed in a jar of pods and let it ride. I didn't even clean it off the rocks - took a 100% hands off approach. No change in lights.
Flash forward a week, the dinos are subsiding. I'd say they are reduced 75% from their peak and the snot strings are gone. In their place, cyano is now breaking out. One spot pretty bad near a monti setosa, but also little spots breaking out all over the tank - mostly where the dinos have disappeared the most. Interesting development since I've never once had cyano in this tank.
Full shot 2 weeks since the rock work replacement:
Biggest Cyano patch:
Dinos receding - comparison shot: (you can see the little red/purple cyano spots breaking out to the right of the base of the torch)
TLDR: it seems that in a mature tank, it's pretty hard to kick off a new nitrogen cycle. There's enough bacteria around on the walls and sump/back chambers to keep things working normal. What does happen though is a new ugly phase, and the major disturbance will bring back old problems and tank imbalances. However, being a mature tank - it seems to work through these phases rather quickly. Tank "rematured" in two weeks what took months prior.
I'll update this thread weekly and I'll document the results. Feel free to ask questions or hijack the thread with your own results. It's all in an effort at sharing information and learning (and this topic isn't well covered IMO). The safest bet is probably to cure the rock in the sump, and replace pieces of it over time. But for those of us with nanos and no sump, sometimes your options are limited.
Thanks
Kongar
