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Starting a 90-gal Bimac Tank

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Dec 3, 2006
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So I've been reading up on TONMO for about a month before I finally decided to register. I'm getting a 90-gal acrylic tank from glasscages.com and building the stand/canopy myself. I haven't kept a saltwater tank before but I know what it entails after reading pretty much every word posted on this site. :wink:

This is sort of a "let me get this straight" thread. I'm just wondering what kind of equipment I would need to keep a bimac.

1. I'm ordering a 48" x 18" x 25" tank (90-gal) so what kind of filtration should I use?
2. Would I be fine using an emperor 400 power filter (which has an 80-gal max) if I used 100% live sand and sufficient live rock?
3. How much live rock in a 90-gal is enough?
4. Can I keep the external canister filter, heater, and protein skimmer all in the tank without having to build a sump? I don't have the tools to create my own sump or wet/dry filter, nor have I done anything like that before.

And I think I'm going to keep 1" very fine live sand, which is what was recommended. Is this a sufficient depth of sand for a bimac? One site said fine sand because coarse sand can damage the octopus' tentacles, another said medium to coarse sand is what they enjoy... I'm not sure what to believe, so I'll be safe and go for fine sand. Then we've got the heater, and I'll need to get a protein skimmer, and I hear they like "actinide" light or something?

Anything else I forgot? And yes I promise I'll fully cycle this tank for three months before I even order my bimac. :razz: Oh and if you can recommend any good brands for the protein skimmer or light strip, it'd be much appreciated.
 

monty

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:welcome: it sounds like you've got all the right questions, to the point where all I can say is that you seem to be on the right track, and I'm sure you'll get expert answers shortly...
 

DHyslop

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My advice is to reconsider on the sump. You don't need to go crazy like I did, you can put together a sump with no special tools. Think about it this way: A 90 gallon acrylic tank is a big-rig truck, not a Volkswagen beetle and no power filter is going to get this convoy on the road!

Canister filters look attractive because they're self-contained but like power filters have very little biological filtration capacity. A lot of people use them intermittently to "polish" their water because of their good mechanical and chemical filtration. Live rock is important but I don't think its adequate for a ceph tank the same way it is for a reef. There's just too much bioload. Make sure you have it, but the amount you get should be more related to how you want your aquascape to look. 1 lb/gallon is a good starting point, more or less to taste.

Skip the live sand. If your live rock is good all sorts of critters from it will colonize the rest of your system. In a few months you'll have live sand whether you bought it or not!

I'm a big fan of wet/dry filters. Tremendous denitrifying capacity. If you insist on not wanting to build your own you can buy one for a reasonable price. Most commercial models are integrated into a sump, so you kill two birds with one stone.

Take a look at these:

CPR Aquatics Wet/Dry

Megaflow Sump Filter

These both look like decent products, but they sure cost a bundle. But what do you get for it? Each is basically a small glass aquarium with a couple pieces of cut glass (custom cut for dollars at a hardware store) glued in place with silicone (a few more dollars), and some plastic balls available on eBay for $20. Even if you don't have tools and haven't done anything like this before, doing something like this isn't unrealistic. If you want to take the plunge and do it I promise we'll all be very helpful :smile:

I've droned on long enough, so I won't get into skimmers. If possible, try to buy your skimmer last so you make sure you get one that fits into the space you have available. A skimmer is the best reason to go ahead and use a sump, because the hang-on-back models aren't very good compared to the more common variety.

Good luck,
 
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Dec 3, 2006
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I went to my LFS today, the guy at the counter recommended I use a fluval 404/405 AS WELL as a power filter. I think he meant for a general SW tank though, I'm not sure if he realized/realizes how much waste an octopus can produce.

I gave a call to glasscages.com and they said for an additional $75 they can drill/make me an overflow with space for two bulkheads at the bottom. I might go for that and make my own sump at the local hardware store (I see tons of FAQs for it all the time). If I have a DIY wet/dry biological filter and liverock, is that sufficient filtration? I dunno though - the canister is so appealing because it's compact, clean, and quiet...

Oh I also heard from the guy at the LFS that heaters can sometimes melt acrylic tanks? Just wondering if that's true or not.

Edit: What if I used both? I wouldn't use an overflow (it'll save me $75), I'll instead ask them to just drill two holes. Have the tank hooked up to the fluval, the fluval into the DIY wet/dry, and have the sump pump the water back into the tank? Is this a good idea?

Edit #2: Oh, also, should I get a black background on the acrylic tank (if I even get an acrylic one)?
 

DHyslop

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Don't put too much stock into what the LFS tells you. First, they don't know anything about cephalopods; second, a frightening portion of LFS don't know anything about aquariums(!) and third, they have a vested interest in selling you things.

I don't have much experience with canisters myself, but I had a conversation about them with a friend of mine who works for an aquarium service company. He was telling me they don't recommend them for their clients because despite being compact, they require a tremendous amount of cleaning, the self priming systems rarely work and whenever you do have maintenance to do it almost always makes a mess.

A DIY wet/dry, live rock and a skimmer will serve you well. You'll need some mechanical filtration before the wet/dry, but you can buy a simple $7 filter sock for that. Using the canister as an overflow won't work--the flow rate into the canister and then to the sump will never exactly match the flow from the sump to the main tank. An overflow always needs to be gravity driven.

Is there a specific reason you're looking at an acrylic tank? If you keep a cold-water octo like a bimac the heater won't be an issue. A black background is a good idea, I think it looks much better. Even if you get a glass tank, a can of spray paint on the back gets the job done.

The overflow requires careful consideration. The typical "reef-ready" overflow carries the trade name Megaflow (you can google it). This can be difficult to make escape-proof.

Dan
 
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Dec 3, 2006
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DHyslop;83843 said:
Don't put too much stock into what the LFS tells you. First, they don't know anything about cephalopods; second, a frightening portion of LFS don't know anything about aquariums(!) and third, they have a vested interest in selling you things.

I don't have much experience with canisters myself, but I had a conversation about them with a friend of mine who works for an aquarium service company. He was telling me they don't recommend them for their clients because despite being compact, they require a tremendous amount of cleaning, the self priming systems rarely work and whenever you do have maintenance to do it almost always makes a mess.

A DIY wet/dry, live rock and a skimmer will serve you well. You'll need some mechanical filtration before the wet/dry, but you can buy a simple $7 filter sock for that. Using the canister as an overflow won't work--the flow rate into the canister and then to the sump will never exactly match the flow from the sump to the main tank. An overflow always needs to be gravity driven.

Is there a specific reason you're looking at an acrylic tank? If you keep a cold-water octo like a bimac the heater won't be an issue. A black background is a good idea, I think it looks much better. Even if you get a glass tank, a can of spray paint on the back gets the job done.

The overflow requires careful consideration. The typical "reef-ready" overflow carries the trade name Megaflow (you can google it). This can be difficult to make escape-proof.

Dan

When I saw the pros/cons list of glass/acrylic, I just liked acrylic more. And off of glasscages, upgrading a tank the same size to acrylic is like $50 so I just thought I'd go for it.

Is there any way to cut live rock out of the equation (FO, or in this case CO tank)? What if I have like, a really, really huge DIY wet/dry sump? Live rock is ridiculously expensive - my LFS says $7 a pound and online the best I found was $3.50-$3.75.

Also, regarding the overflow, I think I saw some stuff online on how to make them octopus-proof.
 

DHyslop

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Live rock is really something that you shouldn't skimp on. You'll be so amazed at how much biodiversity comes from the rock: sometimes I spend hours staring at the tiny crustaceans, snails, brittle stars, tube worms, bristle worms and clams that inhabit an otherwise empty tank.

If you're worried about the staggering cost of the rock, you might consider downgrading the tank--go from a 90g acrylic tank to a glass 75. That might cover the cost of the rock.
 
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You don't have to use ALL live rock. You can add some nice pieces of base rock and it will become "live" over time, as long as you do have SOME live rock to seed it with. I have about 30 pounds of actual live rock in my 75, then about another 50+ pounds of base rock. Lace rock and lava rock look really nice and are very porous.
 
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Dec 3, 2006
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Thanks for all your responses DHyslop and Animal Mother. I guess I'll order like a 40-lb bag of live rock, which is manageable.

Is there any specific live rock that's better than others? I see a lot of different kinds being sold online. Most likely, I'll order from SaltWaterFish.com, they sell 45-50 lb batches of fiji live rock for $185 with free shipping - sweet. :cool2:

And I'll have to build the wet/dry myself within the next two weeks, order the tank and stuff from glasscages.com.... hrm. Things are shaping up!
 

DHyslop

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To be completely honest I get storebought rock even though it usually costs a little more. Basically because I can see what I'm getting! I ordered a box of live rock off the internet once and they were bulky and white, didn't have much left on them that was "live." Not to say that all online retailers are bad, but if you pick it out in person you can make sure you get a nice, porous pink rock.

Dan
 

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