RE-SCAPE with dry rock in established tank

SuthernReefer · May 8, 2023

Have a 75 gallon mixed reef that has been up just under 2 years. I'm wanting to redo my aquascape. Some of the rock used will be what is already in the tank, but about half or more will be new dry rock (marco rock).

I'm curious about cycling the new rock. I know I can add it to the tank, but I don't want to risk a swing in parameters and risk losing coral.

Option 1.
I'm about to do a water change and thinking of using the water from the water change to help cycle the new rock quicker in a trashcan with some flow and heater if needed. My question is, since this water will already have the same parameters as my display, what should I be looking for in the cycle? An ammonia spike? Also would cleaning my filter in that ben help with seeding bacteria and should I add Dr.Tims or anything else?

Option 2.
Don't cycle the dry rock and place it directly in display tank and keep a check on parameter swings. Was thinking of getting ammonia alert badge and some ammonia remover. I have nopox if needed.

Ann Enomy · May 8, 2023

How much more are we talking, A few pieces, or a whole new island?

If substantial I would rockscape dry and cement the pieces together. Aquascaping wet rock sucks. I wouldn't worry about a true cycle if your not adding new livestock. Your old rock and filters will keep doing what they have been doing. If worried you could soak it in the tank water like planned and watch to see if you get spikes in ammonia, nitrate and phosphate. If so you know its coming from the dry rock and may want to try and address it before adding to the tank.

Stephen Glover · May 8, 2023

Option 1 is the safest bet. Ive added a piece of dry rock from time to time without an issue but since you want to double your rock volume you will most likely have a mini cycle. If the rock was previously used you may get some ammonia reading, if not add some source of ammonia and wait about a month, checking parameters weekly.

fish farmer · May 8, 2023

Option 1.

I did something similar recently. I had a big piece of established rock with mushrooms I wanted to move, maybe around 25 percent of my live rock.

I took some old dry rock and some Marco and cycled it in a sealed bucket with water change water, heater and an air stone. I knew there would be organics in the rock so I didn't add anything other than water change water a couple times. I let it sit for about a month and did the transfer. I did get a bit of cyano on my sand bed after the switch and still dealing with it, but I did disturb my sand bed with the shuffle. Other than that, the corals are fine and the new rock has a little covering of green algae and coralline is appearing. Been about 3 months since the switch.

brandon429 · May 8, 2023

ammonia isn't your issue here, it's phosphate. any reef on this site can remove half it's current live rock, and not put it back, and ammonia control on a seneye won't budge. (seneyes are the accurate meter, not subject to thousands of misreads, we can see in searches)

once you use a non seneye meter, api or red sea or salifert, merely moving rocks around in the tank will usually always trigger a false reading due to factors not discovered yet, but are the makeup of the thousands of ammonia misreads on perfectly aged and cycled tanks we can all search out. your new rocks taking up or expressing phosphate, algae, is your issue. this isn't a lack of filter issue. 75 gallons has enough live rock where half of it is still more than you need, if it's located in the display where waste is produced. it is