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15 gal Fluval Flex build


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Hi all I am working on setting up a 15gal fluval flex tank that will eventually, once cycled, house a few small fish (pink skunk clown and royal gramma is what I am thinking so far open to other suggestions that would work). I have a few questions as I continue to plan my build. Note I am in Canada so some items are harder to find here.
Filter media? What it the best choice for media for the flex 15? I have ordered this media tray https://www.etsy.com/.../fluval-flex-9-and-15-gallon... and some filter floss
Also got a fluval sea mini Skimmer for the first chamber.
Light? I am just wanting to do soft corals to keep things simpler but know I will need to change out the light I have two I have been looking at https://bigalscurbside.com/coralife-clip-on-marine-led... and https://bigalscurbside.com/fluval-sea-sea-marine-high... and will be changing the lid out to https://www.etsy.com/.../fluval-flex-lid-clear-or-tinted... as we have cats that would likely try to mess with the tank. I know keeping it clean will be a big factor which isn't an issue. 
list of everything else planned or ordered so far let me know if anything is missing, either to start or plan for adding at a later date.  Edited to reflect new additions ordered
15 gal fluval flex tank
fritz aquatics saltwater bacteria
Dr Tims ammonia
Refractometer and reagent
sunsun jvp 110 for mixing saltwater (will be getting a powerhead for tank as one of my first after set-up upgrades would love recommendation for one)
seachem vibrant sea salt is the salt I am looking at
Caribsea Arag-Alive20 fink Fuji sand
Caribsea Marco Rock- Key largo rock 20lbs (may not use all but will see)
Fluval nano sea skimmer
Anything else I should be getting right away?  
Edited by M_Wonnacott
updating equipment list
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I often check LiveAquaria when researching fish.  Their recommended minimums are sometimes low, sometimes high, and sometimes good; but it's something to start from.  Then I might check against BlueZooAquatics to see what they say.  Remember these are what they say are minimums (not recommended tank sizes).


For the Pink Skunk, LiveAquaria lists the minimum tank size as 30 gallons, and BlueZooAquatics lists it as 24 gallons.  For the Royal Gramma, LiveAquaria  lists the minimum as 30 gallons, and BlueZooAquatics lists it as 24 gallons.  Like I said, they aren't always right, but it's something to consider.


The curse of keeping a small nano reef is that there aren't that many fish choices.  And you can't keep that many fish.  Sometimes the recommended minimum is a swimming room issue, sometimes it's due to territorial behavior, it could be due to needing ample hiding escapes to feel safe, sometimes it's food related, or even something else.  Anyway, the reason we often see the same fish being kept in these smaller tanks, is because there isn't  that much to choose from which works well together.


It's not that unusual for people to want (or try) to push the boundaries.  And that can sometimes work, especially when keeping a single fish.  I imagine that either one of these could be kept as a single occupant in a 15 gallon tank.  But I'm not entirely sure that a full grown adult Pink Skunk and Royal Gramma would work well in the long-term.


The filter media link didn't work for me.  However, filter floss is a popular mechanical media.  Activated carbon is a tried and true chemical media.  But it's arguable that neither one is "needed".  I like using protein skimmers, but they are also optional (especially in a small tank, with a small skimmer, and when using other filter media).


I just don't know anything about the lighting or top options available for this tank to make a comment on them.  But I did notice that you are planning on using oolite sand.  Oolite is often very fine/small grains; some might say too small.  But you don't want to use crushed coral either.  Something in between might work best (like 0.5 to 2 mm grain size).  Plus, dry sand is adequate; live sand isn't necessary when using a bottled bacteria product.  Live sand is usually just regular sand packed in water with some nitrifying bacteria.


For the amount of rock, 1 lb per gallon is plenty.  You could get by with a little less if you wanted.  It's clear that you've been doing some research; and it's good that you are reaching out to us before you get too far along.  Welcome to Nano-Reef!  I hope that we can help you get started off on the right foot.

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Ty for reminding me of that site for the fish info I remember using it years ago when I had my 55 gal.  Looks like from there I would be better to go with an ocellaris clown instead and possibly one of the smaller gobies.  


The link was for a media tray for the flex 15 gal.  I do know I plan now to add marine pure gems as part of the filtration and yes some filter floss as well and carbon.  I did get the fluval nano skimmer for the first chamber but know its not worth adding right away.


I will look at some other sand options and see what the place has ty for that I wondered about it being too fine but hard to tell when I didn't look at it in person yet.  Ty for your help thus far.

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17 minutes ago, M_Wonnacott said:

I do know I plan now to add marine pure gems as part of the filtration

The live rock will be the biological filter; and it sounds like you'll have plenty.  Additional biological media isn't needed (and it becomes another thing you need to keep clean).


18 minutes ago, M_Wonnacott said:

I did get the fluval nano skimmer for the first chamber but know its not worth adding right away.

I'd actually add the skimmer right away and give it time to break in.  However, I'd probably hold off on using the activated carbon; then when you do, you can do so intermittently (when needed).

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Ok so I ended up going with the fuji pink carribsea sand instead.  Also ordered 20lbs of the Marco rock - key largo rock (figure I can choose if I want to use it all in this tank or not, as well as will give me different options for pieces I can choose from) I will likely pick up one or two small pieces or live rock at add as well once I find some good pieces. While I was at it ordered https://www.jlaquatics.com/controllers-testing/test-kits/red-sea/red-sea-reef-foundation-pro-test-kit.html to get to the free shipping since I will need them calcium and mag anyways.  Last test I still need is Phosphate and am thinking of going with the hanna checker for that as price compared to a good test kit seems pretty close here in Canada that I have seen.

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Nice! I’m doing the same thing right now with a Fluval EVO. 

I did 20lb of rock 


filter media I’m thinking of cutting the sponge that came with the tank a little bit to make a little more room to add more: Marine Pure High Performance Biofilter Media GEMS.


I also like Chemi-pure Elite 


looks like your off to a great start I can’t think of anything else right now. I too am debating what light will be best so I’ll be following this thread

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Yes already have some of the gems on the way as well as filter floss.  the chemi pure elite is another thing I have been considering for when my media tray comes in.  I am in the process of refinishing the top of what we are using for the stand.  Which will be done by end of day Tuesday and I think the last of what is needed to get it set-up and cycling will be here by Friday so should be getting it set-up next weekend.  Prob will get my light figured out and ordered next month since I won't really have it on till at least then anyways.  

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15 hours ago, justin43 said:

filter media I’m thinking of cutting the sponge that came with the tank a little bit to make a little more room to add more: Marine Pure High Performance Biofilter Media GEMS.

With live rock in your display, additional bio-media isn't needed (or helpful).  Despite what they might market it as, it's really for tanks that don't have live rock (not enough surface area) in the display.


Additional bio-media won't allow for more bacteria, your tank has more than enough surface area already.  While more surface area won't hurt your tank, bio-media is just another thing that you need to keep clean.  Plus, it can potentially slow the flow through your filter chambers.

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Things are starting to come in for my build and I should have everything to set it up to cycle for this weekend.  also just ordered and Inkbird ITC-306T-WIFI even though the heater I got does havea  controller of sorts I wanted the wifi factor or the inbird after as many issues as I have ready about peoples heaters malfunctioning and overheating there tanks. 

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Before I get started, why are all your links Facebook links, even though they don't look like it?   I'd suggest fixing that.


On 1/18/2023 at 10:31 PM, M_Wonnacott said:

Anything else I should be getting right away?

Based on what you've posted so far (medias shelves, ammonia additives...), I'd suggest at least one good book so that the info you're getting online is more of a supplement.  


Check out either one of Martin Moe's main books for starters....those used to be what "everyone read" before starting a tank.  My library used to have them for borrow when I was starting out, so try there!  Lots of used copies for sale too if that appeals to you.....or there are eBook versions.   Lots of solid base info in those books....a good antidote to online information in most respects.  Another book on livestock wouldn't be a bad move.  Scott Michaels' book on fish has always been a solid choice, but there are others.


For one thing, I don't recommend using the ammonia spike method to start your tank....it's unnecessary and problematic for what seems like most people.  The bottled bacteria would be sufficient.  BUT...  Even the bottled bacteria is extra since you have live sand that's already been populated with bacteria.  Adding ammonia is likely to be a problem for your established live sand....it's only recommended for use on dead media.  (If you haven't read everything on Dr Tim's site about this, you should.....especially the part where he tells you that IT'S UNNECESSARY.  🙂 )


For another, you want about 1 pound per gallon of rock....but you're using dry rock, so the numbers will not match.   I'd stack your tank so that it visually looks about 1/3 full to you – no more.  (Actual live sand – which you got – and live rock make for a much better start.)


I can't emphasize enough the importance of reading some offline resources like the books mentioned.  Online is great for searching specific answers, but the internet is full of bad info mixed with the good info.  Not a good main resource.  Check out this thread for more reading suggestions:  Your Reef Aquarium-Oriented Reading List!

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BTW,  CaribSea's "Special Grade" or "Arag Alive" (non-oolite) or "Ocean Direct" Original are about the best options.   Ocean Direct would be my pick if all were available.

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Well A little quick update the 15 gal fluval flex will now be getting set up as our quarantine tank as just before we set it up we ended up getting an awesome deal on a 40 gal IM Nuvo AIO with maxspec razor light fixture which is now going to be our display tank I am planning to start a thread for that set-up and will be cycling both tanks at the same time.

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