The Reef Tank banner

biocube 29 drastically under 29 gallon at max fill

7K views 29 replies 12 participants last post by  Cdogsailr 
#1 ·
hi new to saltwater/reef tank. began my set up after preliminary research. Went to local store and purchased six 4.4 gallon (= 26.4 gallons) RO DI water jugs bc i read biocube tend to take less than stated amount plus water displacement. filled it with four jugs added 30 pounds sand and about 25 pounds live rock and it's totally full. how can that be? I've read on forums 26 gallons 25 gallons even 22 gallons but 17 gallons? any thoughts? any help would be greatly appreciated.
 
#3 ·
The displacement of Aragonite is 24.6lbs per 1 displaced gallon of seawater.

And Silica Sand is about 22.2lbs per 1 displaced gallon.

So some quick calculations will give you your total volume available.

25lbs rock = 1 Gallon of saltwater

30lbs (Assuming arragonite) sand = 1.22 Gallons of saltwater

So your rock and sand displace 2.22 gallons of water.

And if you filed it with four 4.4 gallon jugs equaling 17.6 gallons. Then your total in tank volume should be 19.82 gallons..

Hmmmmmmm..... Don't know what to tell you there..
 
#6 ·
Not bad for ball-parking...

but be careful with mass and volume equations... it really is apples to oranges as different density rock can displace different volume despite the same weight.
 
#4 ·
sounds plausible.

This is one reason why I advocate for minimalist rock/sand. In small nano tanks, you should use as little rock (and sand) as possible as every gallon counts.
 
#8 ·
Yes, it was a good ballpark calc. Factor in any air that might be trapped in the rock lattice structure or less dense rock and potential differences in aragonite sand. I have seen differences between crushed coral sized substrate and oolite, especially in new tanks. Depending on what he has, any additional air displacement, I have seen surprising little water in some heavily rock/sand-ed tank.
 
#10 ·
no replacement for displacement... :lol:
 
#17 ·
As an owner of a fire breathing 6.2L V8, I can surely attest to this adage :thumbup:

Also, i've found that your standard rectangle aquariums can be under rated. For example, a 10G is 2400 cubic inches (20x12x10), which equates to roughly 10.4 gallons. that is if you filled it to the brim. A 40 Breeder at 36 x 18 x 16 technically is 44 gallons.
 
#12 ·
thanks for the answers

i was instructed to fill the tank 5/8 full while totally empty and mix in the salt using the Koralia to help with dilution. i put in three 4.4 gallons into empty tank and was already about 5/8. so yes 17 gallon included rear chamber. I'm not upset just confused. the jugs are definitely 4.4 the tank is supposed to be 29. there is a huge discrepancy. Even at the higher estimations of water displacement I'm still missing water and my floor is dry so its not leaking out.
 
#13 ·
The tank might be about 29g if it was completely empty (even the false wall removed) and brimmed to the very top. Surprisingly, most tanks of often not quite what they claim to be.
 
#14 ·
i called oceanic

the technical rep there told me oceanic biocube 29 is not 29 gallon its size 29 which means of you would build a glass box around the entire tank i.e lid, bottom and all four sides that box would hold 29 gallons. honestly i dont even think thats the case but he gave me an honest direct answer. thanks all of you for the help.
 
#16 ·
Ahhh, so if you seal the tank, it would displace 29g worth of volume... someone should sue.
 
#22 ·
Forget the math

i spoke to the manufacture. the individual at the company i spoke to himself owns a biocube 29. He told me he has 18 gallons in his tank. i have 30 lbs sand 25 lb LR = 17ish. The correct way according to how he explained it to me was this. when you buy a new biocube 29 the box it comes in should hold 29 gallons.
 
#23 ·
The correct way according to how he explained it to me was this. when you buy a new biocube 29 the box it comes in should hold 29 gallons.
Oh I get it. You bought a 19 gallon biocube and 29 gallon box. Makes perfect sense doesn't it?
 
#29 ·
I have measured the front part of the tank and it is roughly 19" x 15.5" x 15" (wlh) (the bow goes from 15" to 16") so using the calculation I get 19.1 gal. The back sections 1,2 and 3 are 4 x 9 x 6 wide and are 4" deep and 15" high so that adds 1.0 gal, 2.3 gal and 1.6 gal or 4.9 gal and the total water would then be 24.0 gal. I wanted to know since I am filling my tank for the first time as I type this and want to know how much salt to begin with.

I am very disappointed and surprised this hasn't come up in any other reading I have done. I was hesitant to purchase the tank due to some reviews, but there are a lot of success stories on youtube. There needs to be some disclaimer with all these nano tanks as to their real volume so everyone purchasing them can make an informed decision.

Kevin
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top