Can media blocks replace rocks so I can rescape?

rfisher3 · Dec 5, 2023

Hey guys,

I have a 25-gallon reef tank with a few corals. It has been running for over a year now. I don't like my aquascape. Doesn't give me great options for placing corals.

I wanna completely replace the rock that I have with new pieces. They will most likely be dead rock. Non alive rock, lol.

I know doing that would mess my tank up big time! Probably putting it into a cycle again. So I want to avoid it.

Could I add a couple of these blocks here? Genesis Rocks from Polyp Labs. 23,000 square feet of space per block. Would this be able to replace the biological filtration that I have now so I can restart my rocks?

Any thoughts on this would be appreciated.
Thanks.

exnisstech · Dec 5, 2023

Those can work but are really no different than dry rock so you would have to seed it in a running tank for a while before it becomes populated with bacteria to be benificial but should work. I have no idea how much would be needed. I prefer to use live rock rubble over the blocks. If you are going to build a new scape is it possible to build it outside the tank then break up your existing rocks and place then in trays in the sump or do you not have a sump?

rfisher3 · Dec 5, 2023

exnisstech said:
Those can work but are really no different than dry rock so you would have to seed it in a running tank for a while before it becomes populated with bacteria to be benificial but should work. I have no idea how much would be needed. I prefer to use live rock rubble over the blocks. If you are going to build a new scape is it possible to build it outside the tank then break up your existing rocks and place then in trays in the sump or do you not have a sump?

I have an AIO. I was thinking of getting the blocks now and letting them seed for like a month. Maybe I could break up my rock pieces and put them in a large media bag that just hangs out in the tank?

Cell · Dec 5, 2023

I'd recommend checking reviews first. I think some of these products have been known to crumble over time.

exnisstech · Dec 5, 2023

Cell said:
I'd recommend checking reviews first. I think some of these products have been known to crumble over time.

Good idea. I didn't mention it because I haven't tried the brand the OP linked. I had a bunch of marine pure blocks in one sump and over time they crumbled and made a total mess like I had dumped coarse sand in.

rfisher3 said:
. Maybe I could break up my rock pieces and put them in a large media bag that just hangs out in the tank?

That may work but it would have to have decent flow. Your options are somewhat limited rescaping an AIO that is already up and running. Is it possible to add to your existing rock work or maybe move it around?

rfisher3 · Dec 5, 2023

exnisstech said:
Good idea. I didn't mention it because I haven't tried the brand the OP linked. I had a bunch of marine pure blocks in one sump and over time they crumbled and made a total mess like I had dumped coarse sand in.

That may work but it would have to have decent flow. Your options are somewhat limited rescaping an AIO that is already up and running. Is it possible to add to your existing rock work or maybe move it around?

I just hate my rocks. Honestly, I would only keep those Bio Blocks in there for a minimum amount of time. Just using it as a transitional rock. Flow should be a problem. I have 2 Nero 3's in a 25-gallon cube. I can always crank them up.

exnisstech · Dec 5, 2023

rfisher3 said:
I just hate my rocks.

I know the feeling. I have 3 tanks running and did all the rock work myself. Each one gets a little better but I still don't have one that I would say I love. Building a scape I like is the hardest part of setting up a tank for me. Only good thing is none look terrible if you get enough cool corals nems etc on them.

Spare time · Dec 5, 2023

Do you have sand? If so, it should be fine without the blocks. You can also just dump a bottle of biospira in if you are worried.

rfisher3 · Dec 5, 2023

Spare time said:
Do you have sand? If so, it should be fine without the blocks. You can also just dump a bottle of biospira in if you are worried.

Yeah, I have sand. I would rather err on the side of caution.

Spare time · Dec 5, 2023

rfisher3 said:
Yeah, I have sand. I would rather err on the side of caution.

In that case just redo the rock, dump in a big bottle of biospira, and call it a day.

lion king · Dec 5, 2023

Do you have room in a chamber in the back of your AIO. Just take the rock you don't want in your display and break them up and put them in that chamber, then you will lose no biological filtering capabilities.

Sesty22 · Dec 5, 2023

FWIW, I have a 25 gallon that's been up for a couple of years and I just recently re did my scape as well.

I just ripped out the old rock and put in new dry rock that was rinsed to get the dust off, dumped in some bottle bacteria just in case and let it ride. I have 5 small fish and the assorted inverts and coral, everything did fine for me. I tested the water every day and had 5 gallons pre mixed just in case.

I did have a terrible ugly stage though, way worse than when I initially set up the tank so maybe that's something to think about. But all in all I think I worried and thought about it more than I needed to. Just rip it like a Band-Aid!

bobnicaragua · Dec 19, 2023

I would stuff your existing tank with the new dead rock. Let it ride a few months and start pulling out the old rock. Some bio media in the sump wouldn’t hurt.

MrGisonni · Dec 19, 2023

I don't know..... Sounds like trouble to me. The ultimate goal of a reef aquarium is stability and biological diversity. You'll be turning your system on it's ear so to speak. Might be ok, but I wouldn't do it. FWIW

GARRIGA · Dec 19, 2023

At some point I'm going to try these out. Currently running pumice for orchids from Home Depot. Same stuff marketed as Matrix. Been running for 2 plus years and I tend to overfeed as it's in an experimental tank specifically to test decomposition.

What I like about this FX product being that it has larger cavities to create more surface area since these internal structured products might clog from bacteria and unless portions can be removed for deep cleaning with bleach may stay plugged permanently. Same can be said about dry rock. We have just been told they are porous but has anyone checked after several years to determine if there's still water passing through it? To avoid the unknown. I prefer to expand surface area externally since dead bacteria probably get colonized by live bacteria.

aSaltyKlown · Dec 19, 2023

Do you dislike the rocks or is it the scape?

I would remove all the rock and put it into buckets with old tank water. Break them and re make your scape. The rock will be ok out of water for a while as you do this. You can also get a spray bottle and put tank water in to spray the rock down to keep it wet. I've done this many times. I've always added a few pieces of dry rock in as well and removed some of what I had. The new dry rock may go through some uglies, but not like it would if it were all new like you are talking about doing.

If you still want to replace all the rock. Put as much of your old rock in the tank as you can for 3-4 weeks. Break it up if needed as you mentioned. I'd even try to incorporate some of it into the new scape.

No need to buy any bio media when you have it already.

Widdlyscudds · Dec 19, 2023

You could use a sponge filter while you let the new rock seed, would need to run it for at least a week before you took out the old scape and probably let it run for at least a couple weeks until the new scape settles in, would be a very cheap way have a massive biological/mechanical filter