Opinions on 75 gal FOWLR stocklist

[surfnturf]

I am thinking about trying to start up a FOWLR aquarium in a month or 2 (I have had one in the past, but took it apart several years ago), and after doing a fair amount of research I have come up with 2 possible stocklists for my 75 gallon tank. These are by no means final, and any input on the lists is welcome. I would love to get people's opinions on which list makes more sense from a compatibility standpoint, as well as which group of fish people think will look better.

List 1:
1 flame angel (centropyge loriculus)
1 royal gramma (gramma loreto)
1 hi fin red red banded goby with pistol shrimp (stonogobiops nematodes)
1 sailfin blenny (probbly yellow, maybe black) (atrosalaris fuscus)
1 carpenter's flasher wrasse (paracheilinus carpenteri)
2 firefish (mated pair, for compatibility) (nemateleotris magnifica)
3 blue green chromis (will be put in early to help cycle) (chromis viridis)

List 2:
1 yellow watchman goby (cryptocentrus cinctus)
1 diamond watchman goby (valencienna puellaris)
1 midas blenny (ecsenius midas)
1 six line wrasse (pseudocheilinus hexataenia)
2 ocellaris clownfish (amphiprion oscellaris)
3 ignitus anthias (psuedanthias ignitus)

[berkdog]

I can't really speak on those combinations of fish, but I'm sure others here can. Just remember to check out Lee's helpful writeup about this: Fish Stocking Limit - for FO and FOWLR

Also, I would suggest *not* putting in any fish to help cycle the tank. Everyone will tell you how unnecessary it is with modern techniques (live rock, a piece of shrimp, some food, etc), but it's a bad idea for more practical reasons. For one, you'll want to make sure all fish-diseases are given time to die off. For this, you'll have to leave your tank fallow (no fish!) for 8-10 entire weeks (I know, that's a LONG time). Also, you'll need to introduce your fish 1 at a time, each starting in a separate quarantine tank on its own for 6-8 entire weeks (while it is disease free; once disease appears, you'll have to treat and once treatment AND symptoms are gone, the 6-8 week waiting period starts all over).

Since you've had saltwater fish before, I'm sure you understand how important it is to keep your tank disease free and maintain bio security for your fish. That'll keep them healthy and not fighting disease since your system will be clean!

[surfnturf]

After reading more, I totally agree on the cycling thing.


Playing around with some different combinations, here is a the best list I have come up with.

1 flame angel (centropyge loriculus)
1 royal gramma (gramma loreto)
1 hi fin red red banded goby with pistol shrimp (stonogobiops nematodes)
1 carpenter's flasher wrasse (paracheilinus carpenteri)
1 firefish (nemateleotris magnifica)
2 ocellaris clownfish (amphiprion oscellaris)
1 green mandarin (synchiropus splendidus)

I think I have room for one of the following, but I have concerns about their compatibility with the other gobies and mandarin, as well as with the shrimp:
1 sailfin blenny, 1 midas blenny, or 1 diamond or yellow watchman goby.

If anybody has any information about these fish, or any opinions on the entire list in general, I would love to hear it. Thanks

[leebca]

The Mandarin is one of those fishes requiring special care. Be sure you are willing to provide that care. Read this to get an idea of their care: Food Presentation

[surfnturf]

Nice write-up, definitely good information to have. The mandarin was going to be the last, or maybe second to last fish added, (before the flame angel), but either way it wouldn't get in the tank for at least 8 months after it is up and running, by which time there should be plenty of pods for it to eat. It is interesting that you say that they will need supplemental feeding though, as I was under the impression that a 75 gallon tank with live rock would have sufficient food for them (in fact I had a mandarin in my tank when it was set up years ago, and it seemed fine with no special feeding, but maybe I just got lucky). In your experience, is it possible to keep a mandarin with no special feeding if there is enough live rock in the tank (and therefore pods), or is it just a matter of time before it runs out of food and/or dies from poor nutrition?
Also, this is changing the subject, but in a 75 gallon tank, with say 100-125 lbs of live rock, and the above 9 fish in it, how important is a wet/dry filter and sump? Could I get away with one or 2 over the back filters, provided I had enough flow from powerheads in the tank, or is a sump absolutely essential? Also, would I be okay without a skimmer for now? Trying to cut down on the startup cost (I know, wrong hobby right), and I figured that since it was a FOWLR it would be fine with the filtration from the rock and over the back/sump. I would get a skimmer if I decide to move into more of a reef tank.

[leebca]

Overall, the right way to setup a marine system -- any kind of marine system -- is to be able to put everything in and on it that the system needs. Putting one together piecemeal is not good for the life forms. I can appreciate not being able to afford it, but then wait until you can or save up and do it all correctly at one time. As an alternative, consider a smaller system that you can afford now. (Sorry. Don't mean to 'rain on your parade.')

The Mandarins as a group are tricky. Out of 100 captured for the hobby, about less than 3 are alive one year later. The problem isn't just one of quantity of pods, but the kind of pods. In short, the Mandarins don't just eat the pods that live in aquariums -- they eat many more kinds of pods and marine life forms. The pods in the marine aquarium come and go with the changing conditions and, after a while, one pod will dominate the population.

Those pods are only as healthy as the food they eat, and the food they get is only as good as the nutrition available to them. What did you feed your pods? Trick question. They got whatever they could get. This meant the Mandarin only got the nutrition the pods could get.

So, if there are enough pods, the fish suffers in the long term from somewhere between poor to below standard nutrition. The training to prepared foods helps take care of that shortfall. Acquire a healthy Mandarin and yours should live 12 years like mine is.

Rock weight depends upon density, of course. What is really needed is a lot of surface area. When thinking in terms of 'average' rock density, the target for a FOWLR system is about 2 pounds per gallon of water. With substrate, no sump, and not being filled to the brim, you can figure about 67 gallons of water in the system. So, the target is about 135 pounds of live rock. This generally provides enough surface area, together with about a 1 to 1.5 inch substrate to harbor the bacteria needed for an uncrowded aquarium/system.

Circulation should be no less than 10X the total volume without having a sump, and carefully arranged so there are no dead spots in the entire aquarium. So with this arrangement and again an uncrowded tank, the system should be fine without a sump. BUT not without a skimmer. You'll need to think of the skimmer as part of the system from the start. Just like the circulation pumps, these have to be there from the start, along with a carbon filter, mechanical filter, lighting, etc.

Without going into great detail, what do you think produces the most organic wastes? Fish waste or coral waste? Fish waste is very high in a FOWLR and that means a high organic content in the water. Two controls for that are activated carbon and a skimmer. You can get this kind of info from here: What is Water Quality

[surfnturf]

Another great article, thanks. Where would you put the carbon that you talked about? Would you get an over the back filter, and just replace the filter bags with carbon (i know they already have carbon in the bags, but not whole lb)?
As a way to save money, I was thinking about buying only 10-15 lbs of live rock, then putting in uncured rock that I still have lying around from my last tank, (after washing it to remove any organic matter that may still be on it). I am under the impression that this would work just fine, as the live rock would eventually seed the other rock, it would just take a few months. In your experience, are there any other drawbacks to this approach, other than time?

[leebca]

On the 'seeding part' you've been mis-informed. The only thing the base rock will be good for is a surface area for bacteria that is the part called nitrification. You'll need to read more on this: What is Live Rock, Anyway?

There is nothing wrong with what you plan with the rock. Only don't expect it to help much in the way of removing nitrates -- the denitrification part of the nitrogen cycle. If you read the above, what I just wrote will be clear.

A concern about your choice of phrase, 'uncured rock.' It must have been cured at some point? If it is really uncured, you should cure it before putting it into the aquarium. The way to cure rock can be found on the Internet. Scrubbing it as you suggested, is just the first step. Even if you're sure it is ready, test some out in a bucket of salt water, with an airstone running for a few days. If the water remains clear, it is okay.

The carbon can be put in any location where the tank water flows through it. This can be a powered outside filter (e.g., canister type) or overflow type. You'd like the return (filtered water) to be away from the intake of this device.

[surfnturf]

Ok thanks for the link about the live rock. That is the first time I have read about the inability of denitrifying bacteria to reproduce in our aquariums, and therefore transfer from one rock to another. Apart from denitrification, it sounds like using a small amount of live rock to seed the surrounding dead rock should work, although the biodiversity on the dead rock will be limited to those organisms able to reproduce in the tank.
What methods should I look into for providing the denitrification that I will be missing from my rock? I have seen a little about the vodka method and the importance of a deep sand bed, but are there other things I could do to remove the nitrates? (Obviously water changes would be one).

As far as my use of the term "uncured rock", that may have been incorrect, but I wasn't sure what to call it at this point. It was base rock (by your definition because it started as dead rock and was seeded by small pieces of live rock, but it lacked the denitrifying bacteria from true live rock). It has now been outside of the water for at least 3 years, so I assumed all life on it was gone, leaving behind just dead organic material. I said "uncured" because I would think this rock would need to go through the curing process to remove the dead organisms before it was safe to put any animals in with it. Please correct me if any of my above assumptions are untrue in any way.

[leebca]

Just to make sure we are clear -- even dead rock, with sufficient porosity, will provide some denitrification -- just not the level of actual live rock.

If you plan to keep a FOWLR and since fish aren't concerned with nitrates (for the most part), then I wouldn't worry about exporting nitrates. If you want to avoid a sump and refugium, the only two alternatives would be a nitrate chemical remover and/or a deep sand bed. Adding things to the water, like alcohol, is unpredictable and hard to control. Just up your water changes to 25% every three weeks should be enough control.

[surfnturf]

What is your experience with deep sand beds? I have been reading a lot about them, but there seem to be conflicting viewpoints on crucial issues such as sand depth, the need for/harm caused by having sand sifters in your tank, etc. From a combination of sources, I have gathered that the one option would be to treat the sand bed in the tank as purely ornamental, so any benefit I get from it in terms of denitrification is a bonus, and to have the real DSB be in the sump. This would allow me to keep animals such as gobies, pistol, shrimp, etc that would normally disturb the DSB (according to Ron Schimek, who seems to be the expert on this topic), while still getting the benefits of a DSB from the sump. It also seems that the DSB would run just fine in the sump with no lighting.
My only concern with this setup is that some articles mentioned the possible build up of toxic gases in the bottom layers of the DSB, which would decimate the tank if released. For this reason, would it be better to keep the DSB in the main tank with the sand sifters, so that the gases never get a chance to build up to lethal levels? Or is it safe to put it in the sump, as long as it doesn't get disturbed. With this method I would need to change out a portion of the sand every year, and I assume I would need to disconnect the sump from the main tank to do so, to prevent the toxic gases from entering the main tank.
Any information you have on this topic would be much appreciated.

[leebca]

Sorry for being lazy. If I was to write anything about deep sand beds, it would only be to write what I posted in this thread: Deep sand beds

[surfnturf]

Ok, those are the same conflicting ideas I had seen also. Do you know anything about replenishing/replacing a portion of the sand bed periodically? What is the safest way to do this to avoid exposing the main tank to the hydrogen sulfide? Let's assume I put a DSB in my sump, while the sand bed in my main tank will serve mostly as a base for live rock, as well as a home for a goby/shrimp pair.

[leebca]

I've only heard of someone taking out a DSB, never a portion of it. Don't know why anyone would do that. In any event, I don't know anything about that kind of move.

I also don't know anyway to protect the tank from hydrogen sulfide except by not letting it start being made to begin with.

Sorry I couldn't be more help on these.

[surfnturf]

So from what I gather the way to prevent hydrogen sulfide build is to
1)have proper grain size (.2 -.05)
2)make sure the DSB is not disturbed

This should prevent the organic waste from reaching the anaerobic areas of the sand, which is what causes hydrogen sulfide to form.

Is that correct?

p.s. Lee, you have been a huge help, your answers always make me research a lot more because I want to prove you wrong but I never can ha ha.

[leebca]

I should think you'd have better things to do than to prove me wrong. (just kidding)

No. Remember I do suggest disturbing the top layer of the bed to be sure there is no hardening of the surface going on. It doesn't have to be 'all' disturbed unless you find a crust developing or developed.

The bacteria that make the hydrogen sulfide need an anaerobic environment, and they need nutrition. So in the case of the DSB, the object is to prevent at least one of these, or controlling both. No matter how well the tank is maintained, there will always be dissolved organics (that's what a skimmer takes out, right?). Those organics will go as far down into the bed as the aerobic bacteria are in the DSB and hopefully be consumed at that level. The other control left to prevent the hydrogen sulfide is to not provide a totally oxygen-free environment. Goal: -- keeping the DSB anoxic at the bottom. This is accomplished through selection of substrate (particle) size, and depth of DSB primarily, keeping the water properly gassed, encouraging gas exchange, and I add one more -- making sure the surface doesn't become blocked (form a crust).

The organics I may have mentioned, as well as some others are the detritus build up including marine life form wastes, uneaten foods, dead algae, dead micro life, dead benthos life, etc. Those need to be removed frequently and definitely not encouraged to work their way deeper into the DSB. With regards to benthos life -- that is a big debate. Probably those that reside on the substrate surface are okay. However, if their benthic zone is deep enough so they can die unnoticed and/or release their wastes deep in the DSB, then they bring the nutrition to the lower regions of the DSB. If they aren't present. . .no worries then.

[surfnturf]

Interesting. Have you read this article by Ron Shimek? He says that the worms and other organisms in the sand bed will prevent any clumps from forming, so there is no need to disturb it manually. Also, the main benefit of a DSB (at least for me) is the denitrification that is performed in the anaerobic portions of the sand, so preventing these areas from forming in order to avoid hydrogen sulfide seems to defeat the purpose of having a DSB.

Ron Shimek's Website...Deep Sand Beds

[leebca]

I have read most of his articles and the pamphlet I have recommended. The area where denitrification takes place only needs to be anoxic. However those bacteria that produce hydrogen sulfide do need anaerobic areas.

I only recommend disturbing the top layer if/when:
1. necessary and/or
2. benthic creatures don't.

I do not take sides on to put benthic creatures in or not. I can see both sides of the debate -- but there IS a debate on that.

[surfnturf]

Ok, assuming I put a DSB in my sump, and a 2-3" sand bed in the main, what if anything would you recommend as far as maintaining the DSB?

Cleaning a Sand bed - The Talkingreef Community

About 5 posts down in that forum, a member talks about cleaning his DSB by sticking a tube into the sand with his thumb over it, releasing his thumb to draw up the sand, then lifting the tube so the sand falls out on top of the other sand. He does this in small sections every time he cleans the tank, so over time the entire sand bed gets turned over. Do you think it makes sense to do this, in order to prevent the build up of completely anaerobic zones and release any hydrogen sulfide that does build up in small sections rather than all at once? Or is this just killing the denitrifying bacteria and releasing potentially harmful gases into the tank?

I should mention, that I've been following his build thread started a few years ago, and his nitrate levels have not been above 10 ppm since cycling ended. He has all top of the line equipment and he has still had a large number of deaths in his tank, so I'm not sure if he is exceeding becasue of his cleaning method, or in spite of it.

[leebca]

Hmmm. I've not heard of doing that. It strikes me as being counter-productive. You might not kill the denitrification bacteria, but their activity would come to a stand still until the aerobic bacteria removed excess oxygen.

Before I could back that process, someone would need to convince me that the organics have indeed reached that level and do indeed pose a problem. But as a prophylactic move -- I don't think so. Hate to speak in clichés but, 'If it ain't broke. . .'

A properly functioning and designed DSB should provide a near zero nitrate level almost all the time. 10 ppm would be higher than I would expect such a system to yield.