Translating Rules to Large Tanks and Other Sacred Cows

[GoToSleep]

So everyone knows of the rules of thumb for reef tanks re...
lighting watts per gallon
live rock punds per gallon
water flow as a multiple of display tank volume

How do these rules hold up as you head into bigger tanks? I'm planning a 550gal display (72x36x49) with another 80gal in the sump/fuge plus some smaller tanks (40g specimen tank, 40g prop tank) plumbed into the system. Total volume around 700 gal.

Following some of the rules, I would need 5,000 -10,000 watts of lighting, 1,000-1,400 punds of live rock, and 7,000gal/hr flow.

I think that I can throw the light numbers out the window... I'm planning 3 x 400W MH for SPS and clams. (any thoughts?)

What so you suggest for live rock mass and water movement?

 

[troylee]

The watts per gallon is no good period......a 120watts of pcs won't light a 20gal tall suffectiantly.......we all know that.....but the rocks and turnover I would stick with, for denitrifying purposes and oxegeonation...spelling???? Man I know I'm way off lol....

 

[Reefaquariumnut]

7,000 gl/hr is not enough. I have around 50,000+ in my 600 and it seems okay.

With regard to rock...Depends on live or dead and dry or wet. live wet rock I would do 1000lb, but dry and dead you could get away with 500lb. Also depends on the size and shape obv.

 

[sfsuphysics]

lighting watts per gallon

IMO this should be ditched even with the smallest tanks!
It's about how the light is used, and where you want it. I think the WPG rule came up back in the day of normal output fluorescent bulbs... could be wrong about that You can stagger lights, you can put lights on a mover, or hell you can have parts of the tank that aren't as bright as others, hell I do. Hell on my 180g 100% (practically) stony tank, I have 4 watts per gallon (2x 250w halides, 4x 54w T5s). Of which the T5s are the blue & actinic bulbs (so watt for watt they're not the same), and the halides are only on 5.5 hours a day.

However looking at your tank, do I read that right of 49 inches deep? That is a REALLY tall tank, and you're going to need some strong light to punch through to the bottom if you want to keep anything that requires "high light" there. In fact it depends what you want to keep in general that'll dictate your lighting. Definitely would do at least 400w bulbs... lumenarc or lumenbright reflectors, you'll have some "darker" spots.. but I'd toss in some blue T5s or something so you get a bit of color. Another option is to go with 600 watt bulbs if you want to get a lot more power to the bottom of that tall tank, check out pacific garden supply, they can handle your bulb needs too.

live rock punds per gallon

Throw this out the window too. Live rock you NEED? Let your skimmer you get for that tank be your primary means of filtration, let your rock be places to put your corals and let your fish hide.

Again with that tall tank, you'll need to get creative with stacking if you want to get anything up there (rods, zip-ties, etc). Why again are you going with such a tall tank??.

water flow as a multiple of display tank volume

Water flow will most likely make or break your big tank. However with larger tanks, and the way technology has gone (oscillating pumps, etc) the actual X-times turn over rates get a bit tricky. This was mentioned in another thread, but if you had a gyre effect, you could get very fast water velocity with relatively little pumps if everything was set up correctly. However with most tanks that we like to look at, they aren't .

Telling you how much flow you need is going to depend upon a lot of things. I've heard 60x turn over for SPS tanks, which is nice... however as I mentioned before the velocity of the flow is more important than how much your pumps move. The way your rocks are stacked with respect to your pumps, amongst other things can influence the velocity greatly. For one tank pumps that do 20x might be sufficient, for another 80x might not be sufficient.

 

[sciknen]

I do think he was seirous about the 4ft deep..thats 550g


If i were to do that i would look into some solar tubes or 1000wers

check out the John Cena Build Thread.. his is about i think 6 ft deep?

 

[GoToSleep]

Yes indeed, I'm crazy enough to build a 4 foot deep tank. I originally was thinking of the Marineland 72x36 300gal but my room has 12 foot ceilings and I thought that a deeper tank would have more of a 'presence' in the space. Anything bigger than the 300gal put me into the land of custom tanks and I was suprised to learn that a 49.5" deep tank wouldn't really cost much more than a 30" deep tank as costs don't change much if you stay with a standard size piece of glass. So my 72x36x49.5 should be delivered in a week or two.

My hope is that with the right reflectors, I can punch 400W MH's deep enough for SPS and Clams.

My tank is visible from 3 sides so I'm not sure that there's any attractive way to do a gyre tank though it would be nice with the tangs I plan to keep.

 

[JustinReef]

I don't think there is any way 400's will be enough. I had 400's in very good Lumenbright reflectors (probably one of the best for penetration) over a 22" tank and it was great but PAR readings on the bottom were not nearly as high as I would have though. Your going more than double that! The Lumenbrights are great for depth penetration but you then have to remember you don't get all that much spread.

I don't know as I have never had to light such a deep tank but I don't think 400's will be enough if you want SPS half way down the tank.

I would go with 1000's from the beginning maybe so that you don't have to buy lights twice.

 

[GoToSleep]

<a href=showthread.php?s=&postid=15197165#post15197165 target=_blank>Originally posted</a> by JustinReef
I don't think there is any way 400's will be enough. I had 400's in very good Lumenbright reflectors (probably one of the best for penetration) over a 22" tank and it was great but PAR readings on the bottom were not nearly as high as I would have though. Your going more than double that! The Lumenbrights are great for depth penetration but you then have to remember you don't get all that much spread.

I don't know as I have never had to light such a deep tank but I don't think 400's will be enough if you want SPS half way down the tank.

I would go with 1000's from the beginning maybe so that you don't have to buy lights twice.

My LFS has a 1200gal reef that is this deep and it looks great. I'm pretty sure they're using 400W MH's. My primary concern with 1000's is the heat. I'm hoping to not need a chiller bigger than my central AC for the house.

 

[serpentman]

Keep in mind that PAR decreases exponentially with depth. 400W with LB or similar reflectors mounted relatively close to the surface might penetrate deep enough for some softies, zoos, etc at the bottom. You can always mount higher light species accordingly. Bulb choice will be crucial as the more PAR you start with, the better chance you have.

As far as the rules, all are meant to be broken. I think most are meant to get newbies on the correct path. For example, most people start out with low budget equipment, so the rules make more sense.

Crappy skimmer means you need more rock.

PC lighting means you will need a lot more Watt/gal

As far as flow goes, I think this is probably the most crucial and should be scaled based on the size of the tank and its dimensions. I aim for 40-50x turnover per hour. However, the key is to make sure it hits all areas of the tank.

 

[GoToSleep]

Serpentman,

What is a 'nano tang' and can I keep one rule in a 10 gal cube?


"Crappy skimmer means you need more rock" -- I'm planning on using the new Alpha 300 Cone Skimmer by the guys who make Bubble King. Hoprully this will get the job done.

 

[serpentman]

It's more or less a poke at a particular element here on RC. FYI, they can only be kept in groups of 3 in a 10g or less.

 

[porthios]

i also feel those rules are pretty much worthless for any size tank and think you'll have a hard time with clams on the substrate that far below 400w bulbs. i'd be inclined to start with 1000 watters myself.

jmho..

check out this video for a good gyre setup on a pennisula style tank. my build thread shows the same idea.