How many lbs of Rock should be added to a 32 gallon reef tank?

Jan Cavalieri

Fish Addict
Pet of the Month!
Joined
Jun 2, 2019
Messages
899
Reaction score
299
Location
Topeka, KS
About 6 months ago I bought a Biocube and stand for about $600 on Amazon. This is a 32 gallon tank with strip of holes for water to spill over into the sump in the back where you can have a protein skimmer, lots of different filtration media and a chamber for the heater and thermometer and possibly a UV sterilizer to shine on the light before it is returned to the tank It actually comes with 3 separate sections leaving two huge sections just for filtration. People decided that was way more than a tank that size needed so they came up with something that 1, Divides chamber 2 in to two chambers and 2. Forces the water to fall directly on the media. I guess there has been trouble when it was one great big space getting the water to go through all the filtration, This supposedly forces the water to go through it. So the first chamber has your protein skimmer, the 2nd chamber is still big enough to have more filtration than is in a large HOB filter. Chamber 3 can be anything you want it to use it for - most likely a heater. Before they had the heater in the last chamber with the return pump and you would be very limited in the size and style of any heater you purchased, With 4 chambers, chamber 3 is big enough not to be too limiting. Then some people try to squeeze in a UV sterilizer (some people say that's unnecessary) in which the 4th chamber would just contain your return pump and pipe to force that superclean water back in to the display tank in the front, Kind of dissapointed it doesn't use any socks because I always thought those were really funny looking but I can live with it.

My interest in this tank is primarily for the corals - the fish and other creatures I'm only somewhat interested in. Having such a small tank to work with you are pretty limited in the type of saltwater fish you can have in a reef tank. For example, having Tangs is out of the question but a couple of clown fish and maybe one other fish related to the Nemo theme could be added. I'm not that familiar with the characters of the cartoon but I'm sure my daughter and granddaughter help me with this. I know shrimp are beneficial but seeing these thing alive when they are one of my most favorite foods kind of grosses me out.
Soooo........

After a couple weeks of finally having time to work on it, right now I've finally built a structure of reef that i love, but it's really heavy - based on how much rock I have left over from the 40 lbs that I purchased I have built a structure that is about 34 lbs of rock. There are a large number of solidly built caves and passthroughs and since I only plan to have about 5 fish in the tank I thought maybe it would be ok to make the emphasis on the reefl A while agp I ran across a website that saod that for a 32 gallon tank I shouldn't have more than about 11 kilos of rock in it (ie., 24 bounds), I said,to myself "I don't care how heavy it is, I like it" but now wonder if there is a good reason I'm not aware of to limit how much rock you put into your reef. This is dry rock that is sprayed purple in color. I guess that will become "activated as soon as I fill the tank with salt water. I assume they recommend the smaller amount of rock to make sure your fish and other moving creatures have plenty of room to swim around. My reef is rather short and sprawling leaving a lot of room at the top and even the middle for fish to swim. I have no intention of buying more than 5 fish or "creatures" and that the bulk of the tank will be eventually covered in corals.

I'm ready to start making the RO/DI water any day and adding salt to it and then adding it to the tank so if would like your opinions and thoughts about tis? HELP???? I plan to cycle the tank just like a freshwater so i guess i can still use Ammonia and bottled saltwater bacteria. Is there anything serious i am missing? There are no sources for corol where I live plus I'm pretty much homebound being on oxgen 24/7, I have a young man that assists me each Friday doing water changes and anything else I need. He's moved a little slow but now seems to have a good understanding of the nitrogen cycle as well as the ability to recognie issues in freshwater fish but the Saltwater aquarium will be my baby - he won't be doing much until I've become more familiar on the way things work. Plus right now we are cycling a 90 gallon tank for 4 DoJo loaches that have become so large (14 inches) and eat and poop so much that they foul up their 50 gallon tank in about 3 days. I pay him by the tank but since this one is so large I'll be paying him for the equivalent of two tanks. Once our 50 gallon is emply of dojos we are tossing all the sand and filtration that goes with the tank and i'm likely buying a Fluval canister filter for it. We've had some serious deaths of non-dojo fish in that tank and while it could just be due to all the waste the Dojos produce I don't want to take any chances and continue to have the same '"white algae bloom" I've been fighting for over a year when the dojos were in it - once it's clean I'll be moving the contents of my 29 gallon tank into the 50 gallon tank - there are quite a few young Plecos and Gourami and a few glass fish that I want to see in a bigger tank as they all grow up. So he'll have two large tanks to clean while I'll have the saltwater tank I'm sure I'll pay him more since the tanks are so much bigger, My 90 gallon just started to to cycle about a weekago so its got a ways to go.

Any suggestions, helpful tijps etc would be welcome Thank you!
 

Donya

Crazy Crab Lady
Staff member
Moderator
Global Moderator
Joined
Jul 23, 2004
Messages
3,993
Reaction score
155
Location
Northeastern USA
The weight per gallon guidelines all assume medium to light density rock. It's completely ok to have more weight as long as the tank bottom is well supported. The only reason to be skimpy on rock is if you plan to get a lot of large, established corals that are already attached to a big piece of rock. Most people get frags though and grow them out.

UV sterilizers can actually be bad for small tanks because they kill good microbes along with any bad ones. Beneficial bacteria and plankton that get zapped by the sterilizer then decay and add to your waste levels. UV sterilizers should really be reserved for rather special situations where minimal micro-fauna is required or when treating certain fish diseases.

Regarding cycling, is the rock you have now dry or live? Live rock is purchased wet and covered with algae and other living things - it's the biological filter for most marine tanks rather than traditional fw-style filter media. Since it sounds like the tank isn't filled yet I'm guessing the rock is dry. You will have a much easier time of things if you start with at least some live rock once the tank is filled.

For live rock, the cycling situation is different than trying to colonize dry rock and you often don't have a traditional cycle period. When starting a tank with live rock, the next thing to go in would be clean-up crew animals for a while before fish. Usually people start with at least some live rock which acts as the initial filter because dry rock takes a LONG time to colonize, but it does become colonized over time by the live rock.
 
OP
Jan Cavalieri

Jan Cavalieri

Fish Addict
Pet of the Month!
Joined
Jun 2, 2019
Messages
899
Reaction score
299
Location
Topeka, KS
A while back I posted about how my of the dry "life" rock I was going to use and somebody said I was using too much (without any explanation). They also said to ditch the UV sterilizer (without giving the nice explanation that you did) - so the UV sterilizer will go unused. I'm a little hesitant to put live rock in my tank since every book I've read says not to becuase of the high number of undesirable critters that come with it. But if I did get one Live Rock it sounds like you don't need to cycle the tank just add the clean-up brigade and then fish? Everything I've been told about cycling a salt water tank has said to do it exactly like you would for a freshwater tank - add ammonia etc. Are you saying don't cycle the tank? I was talked in to the dry rock which supposedly has been sprayed with good bacteria and such without the rish of getting anything bad in you tank. I'm really getting confused (another reason I've had this tank 6 months and haven't even started work on it. I also haven't found any place that will sell me a single live rock - they all want to sell at least 10 lbs for around $300.. Locally we only have two big box pet stores and a single small owner fish store, he does sell live rock in 10 lb batches but he is such an asshole I won't buy from him. My first visit I was looking for Gorami and he sold me a chichlid - telling me that it was a Gourami. Of course it wasn't and caused agression issues for months until I found somebody to take it off my hands. He also has a huge group of piranha and will feed them for you for $5. (oh and NO cover on the tank - anybody could stick their hand in). I watched him feed them after the parents of 3 young boys wanted to see it and the 4 yr old was crying hysterically telling all the "babies" to hide. Their middle child just turned his back away and refused to watch so only the oldest boy and his parents (and me, for about 2 minutes) watched. It was the sickest thing I've ever seen. I realize they have to eat and they eat quite violently but don't put them in your store especially without a lid! Anyway - I'll look around on the Internet and see if I can find someplace that will sell one or two pieces of live rock and see how it goes. In the meantime I'll read up some more on how to cycle a salt water tank, Oh my dry "life" rock is very porous to hold bacteria - plus my reef has so many great caves and pass throughs I don't want to touch that part.

Thank you so much for responding!
 
OP
Jan Cavalieri

Jan Cavalieri

Fish Addict
Pet of the Month!
Joined
Jun 2, 2019
Messages
899
Reaction score
299
Location
Topeka, KS
OK, I was on the Bulk Reef Supply website and they sell UV light, after UV light in every size you can imagine. So if UV light is such a bad thing why would they sell so many different types? Also I watched several of their videos and not once was it mentioned that you need a wet live rock to cycle the tank. In fact they discourage people from using wet live rock because of all the nasty micoorganisms that tend to arrive with them even if you cure them for long periods. They did like the live rock that is submerged near real reefs then removed after several years and broken down for selling. They too have microrganism issues so you still have to cure them. But what they were primarily interested in was how porous the rock was - live or life rock and some of the most porous were some life rocks. I just don't know what to think any more. Books contradict each other, as do the videos on reef building. Who to believe?
 

xxBarneyxx

Fish Aficionado
Joined
Oct 28, 2006
Messages
3,530
Reaction score
589
Location
Kent, UK
So a few things to unpick here, I will try and give my opinion on what I would do.

UV Light
UV lights are used in a lot of marine setups purely because a lot of marine fish are an absolute nightmare for whitespot. Also lets be honest, if you are getting into marine tanks you probably are dropping some significant cash on them. This means a lot of expensive gear is put to market as manufacturers know people will buy it.

For a mostly Coral/Invert tank it absolutely is not needed. As @Donya said it can actually be a detriment as it kills good micro-organisms along with the bad ones.

I have UV filters. I only use them in two situations:
1) I have an outbreak of a disease that is waterborne and UV will help. I then set up and use the UV until it is taken care of and then remove it again.
2) I'm keeping a fish like a Blue or Yellow tang that are really prone to getting whitespot. With these fish I will have one running all the time.

Rock Quantity:
As in the above answers the weight can depend on your rock density. Can you get any pictures of your setup and the rock?

Is the rock you have nice and porous with lots of holes in it?

If it is then around 30lbs of rock is about right. It doesn't have to be dead on, a little more or a little less wont hurt.

I would recommend getting some "eggcrate" which is used in lighting and put that on the bottom of the tank and putting the rock on to that. It distributes the weight better and makes the rock more stable as it is less likely to slide.

Your dry rock
From the sounds of it you have dry rock. You said it was "sprayed purple"?

Is it literally sprayed purple or is it sprayed with a coralline algae "starting culture" that will grow once it gets in the water?

If it is literally sprayed purple I would be very concerned about using it as you don't want any type of chemicals in a reef tank.

Cycling a marine tank using Rock - Basics.
Sorry if I cover stuff you already know but I don't want to make assumptions and maybe miss something important.

So a marine tank works much the same way as a freshwater tank in terms of the nitrogen cycle. Bacteria convert ammonia to nitrite, other bacteria then convert nitrite to nitrate.

The difference in marine tanks with "liverock" is that all the bacteria is contained within the rock work instead of in a filter like it is with freshwater tanks. This is one of the reasons why you need really good water flow around the tank, at least X30 times the tank volume. This means the water is flowing all around and through these rocks with your bacteria colonies in.

Cycling with "Dry/Dead" Rock
Basically Dry/dead rock is rock that has been completely dried out and contains no beneficial bacteria. It can be either natural or man made. Think of it like a "new filter" in a freshwater tank. It needs to have bacteria grown on it to take care of the nitrogen cycle.

This is done in exactly the same way as you would a freshwater tank. Get some bottled ammonia and follow the normal fishless cycling methods.

Once you have completed the cycle you can now consider your rock to be "live rock". As such make sure you are not removing it from the tank for any prolonged periods of time. The tank is now cycled and you can begin stocking. I would still recommend stocking slowly though, especially the corals.

Cycling with "Live rock"
Live rock generally refers to rock that already has a lot of bacteria and other organisms growing on it. As such it needs to be kept in the correct conditions to keep as much of that stuff alive as possible.

Live rock will normally come directly from the ocean, so yes, you often do not know what is coming in on it. However in my opinion that is one of the best parts of owning a marine tank, seeing what you have and what develops over time. Yes there is a risk of pests but there is also a very good chance you will get beneficial stuff as well.

Now as live rock is already packed with living stuff when you transfer it into your tank there will already be a bunch of useful bacteria for dealing with the nitrogen cycle. However there will also be a bunch of stuff that dies off in the process.

How much die off there is depends a lot on the rock, where it came from and your tank parameters. If you get live rock from a marine aquarium that is already well established and keep it wet while moving it then you will get very little die off.

If it comes from the ocean and it is getting shipped across the country, maybe sitting in a holding tank with bad water quality for a bit, then you might get a lot of die of.

The way you deal with this is by "curing" your live rock. This is simply setting it up and letting nature run its course. Test for Ammonia and Nitrite regularly. Once these zero out, give it a week or so longer to make sure they stay zero and then you are good to go.

During this process I personally recommend doing regular water changes. Sometimes a big die off at the start creates a massive ammonia spike, this then kills off more stuff in the rocks, which creates more ammonia and it prolongs the cycle for a lot longer. Keeping the ammonia/nitrite levels as low as possible prevents as much die off and speeds things up. It also helps keep more critters alive.

Mixing Liverock with Dry rock.
Basically think of this as cycling a freshwater tank but taking some filter media out of an established tank.

Cycle it the same as you would with just dry rock, adding ammonia and doing a fishless cycle. However the Liverock will help speed up the process by giving a starting colony of beneficial bacteria to get started with. It also introduces a bunch of micro organisms which, in my opinion, are really useful for a reef tank.

Which method is best?
Personally I feel a little conflicted about using actual live rock removed from the oceans nowadays. I would prefer to go for man made dry rock for the majority of the rockwork and then either get live rock from an establish tank that is being shut down or some man made rock that has been "seeded" in some way.

I don't ethically feel that we should be using "real" live rock anymore as it is actively destroying environments that we should be doing everything we can to protect.

Ethics aside doing it this way gives you the best of both worlds. You get a lot of cheaper cost rock with no pests and you get some live rock from a established tank that you can see has no pests to seed the rest with.
 
Last edited:
OP
Jan Cavalieri

Jan Cavalieri

Fish Addict
Pet of the Month!
Joined
Jun 2, 2019
Messages
899
Reaction score
299
Location
Topeka, KS
Great information. Thank you. I'll run some tests on the water and see where I am with ammonia and nitrites and then add ammonia and let the cycling begin. I also may need to adjust the PH - although I've read that PH is automatically adjusted by the chemicals in the salt you are adding. Our tap water has a PH of 9.4 - so I use a neutralizer to bring it down to exactly 7.0. It's worked well for a long time for me. But, shouldn't the PH of a saltwater tank be around 8.0? Should I bother with a PHdown if my PH is still reading 9,4. I hate using this stuff because it's like a guessing game if you want to hit 8.0 exactly.

As far as the pieces of live rock I received, they took some good pourous rock and sunk it with a rope attached for many months in the ocean. Then the pull it out and see if it is now true live rock and break it into pieces. They too don't believe in stealing reef from the ocean.

As far as the coroline - it wasn't clear to me at the time but I think they sprayed it purple with bacteria on it. If you break it in half it is white inside. So my assumption was that I was getting painted on bacteria. The live rock is all brownish but I figure that won't matter after a while.

One more question - the hose that returns clean water to the tank is very high power. My substrate is live sand and it is blowing it around everywhere. Will there be a time when that stops - will this blow the corals off their rocks?

I'd send a picture but you'd just see white from all the sand (that I rinsed and rinsed) and wouldn't be able to see the rock. If it ever clears up I'll put up a picture. It certainly gives off a powerrful stream of water.

Thanks again.
 

Most reactions

trending

Staff online

Top