Flow Rate, Turnover, Water Movement

You read quite a bit about flow rate, and minimum turnover for reef tanks, etc. I was wondering what precisely is this referring to. Let's say I have a 100 gal tank with a wet/dry, which has a 5 gal. capacity. Stick with me, this is not real life.

If I placed a huge capacity return pump in my w/d, let's say, 1000 gph, then we have a 10x turnover, assuming 1000 gph with a 4' head. Now, the benefits are clear, and well discussed on these forums. Water is oxygenated by the cascade down into the w/d, the flow of 1000 gph will create the necessary turbulence that corals love, detritus would never have a chance to precipitate and collect on the sandy bottom, the bio balls will aid greatly along with the LR in nitrification. A really high quality skimmer could be placed into the w/d and the equasion is complete. Right???

In my mind, it is for all the above reasons that minimum turnover rates are advised. A popular rate I've read is 10x/hr.

Here's where I'm confused. Let's say for sake of argument that I devise some new method to oxygenate the water without it ever having to leave the main tank, (just making a point, not real life, remember). Additionally, I stuff over 180 lbs of LR into this 100 gal tank. All this LR would negate the need for bio balls (besides, word has it they're nitrate pumps anyway, right?). Finally, I hang a really efficient skimmer on the back of my tank.

So let's spend 800 bucks and throw two vortech wireless wavemakers running in reef crest mode, each driven off the other in opposite synch. Now we have "simulated" more than 10x turnover per hour. So we've achieved a scenario where not a single drop of water needs to be "turned over," right?

There's my question. Is suggested "turnover" just a figure to recreate the ebb and flow of the ocean so corals get fed, detritus doesn't accumulate and water gets oxygenated; or is it a must for water to leave the tank and re-enter 10x per hour for some reason?

Am I the only one, or has anyone ever given this any thought?

My suspicion is that as long as water movement takes place, nitrification and oxygenation of water takes place, protein skimming is efficient and lighting is sufficient, "turnover" is a dead issue.

True?

 

Sounds very interesting but you also have to take into consideration the bio load, lighting, filter media and feeding. It always sounds and looks better on paper;D

 

It depnds on subtrate and critters

HI,
In my tanks extremes can be a pain and move a lot of sand so I try to buffer the rate of return, or you may be drilling the bottom of the tank similar to that strip mining hehe
Now if I do my tank over oneday, I may go with a rock only tank with power heads to increase flow. WOuld prefer pre-drilled tanks, and a mud sump thats twice the capicity I need with a reforguim
I just like the rock only tank's they look so cool.
I could build some pvc pipe stands to pile the rocks and prevent those avalanches and to allow water thru and under the rocks.
To answer your question depends on corals and animals in the tank.
Some like high flow other like medium to light flow, and some prefer wave actions.
Complex question no simple answer.
Doug

 

Yes well this is just one of the subjects all the new experts like to talk about and really have not a clue as to what the hell they are saying all to get their names out on the net.. As I say all the time Electrical and plumbing HVAC mechanicals are not a hobby and these have been my line of work for over 45 yrs . As a Class A mechanical Cont in Va In this field I do consider myself a expert.. From system's design to installations

First off using your 100 gallon size of tank, and what the experts write about lets say 10 x turn over .. I can't happen no way in hell could you ever remove a 1,000 gph of water from the tank with just 2 inch drain lines thats even if you have two and no HOB will handle that amount either about 600 gph is all you will get to the sump..

And all aquarium pumps are far over rated in their ability to really move the water they advertise they can.. Then take them from the box and use them in the real there are to many variables to even guess what they will do salinity and temp all had to hydrostatic head pressure and more are rated with F/water and you loose about 10% right off with saltwater at 1.022 gravity. But they 1,200 GPH pump will do fine because it will only give about 600 GPH on the average tank.. And the average best flow rates from the tank through the sump is 4 to 5 x's per Hr. and that will leave you a little extra hump of the pump to keep the levels always steady the piping will regulate the true flows Also all the water from the tank should never be pushed over the bio chamber you only want to bleed off about 20% to run over the bio media of the W/D the rest of the drain water is on a bypass to the sump.

Now another one that kills me is the term closed loop its a lot of things but not a closed loop LOL Its a open recirculating loop.. Again some aquarium expert not knowing what they where talking about coned the term closed loop .. But here is where you get what they also misconstrue with flow rates Its not a flow rate but rather a recirculation rate and this is where you get the water movements from .. Then on these is where you want a High Volume pump and not a high pressure pump.. Like the Dolphins amp masters they push about 4,000 gph at zero head and about 2,500 at 5 ft is piped properly but won't shoot water more then a few foot on a open pipe end..No pressure at all just volume.. Like a garden hose with no nozzle on it gives more far far GPH then it will with the nozzle set to shoot water out to 50ft.

On the internal circulation you can add power heads or vortec's all will move water but what you want is high volume pumps that incorporate a propeller and not a impeller like a maxi jet.. You just want to keep as much solids in suspension as you can for filtration, water, quality and coral rinsing purposes . This is just a fast start to what circulation and flow rates really mean. And at the end of the day all the internal turn over is for more then holding solids and water in suspension it is to move the water around and down and up in the tank for surface gas exchange. Oxygen is the main reason. Thats where 90% of the exchange happens..

 

And then one time at band camp........

Wow that was alot to take in I just have one Q for Tangster , can you either here or on another post go abit more into detail about the benifits and disadvantages of propeller and impeller type P/H please.:thumb_up:

sorry to go off topic RF

 

http://www.3reef.com/forums/filters-etc/wave2k-44750.html

Here are my wave 2ks I use for wavemaking.

 

Thats simple A propeller type pump move much larger volumes of water over a shorter distance then a impeller type does. Its like the difference of a Rifle opposed to a shot gun .. A rifle is better for a shot a mile away on a elk standing still where as a Shot gun is better for a close shot at a running deer As the shot spreads out into a wider pattern and covers more area. And its more about the volume of water movement in the reef aquarium rather the pressure of a shooting stream . The GPH is just another is the common misnomers used in the hobby.. Also anyone here using the propeller conversions on a maxi jet ? I'm curious as to how they are working out for the people if any did the conversions . Another example just came to mind after many yrs racing Offshore boats a Propeller will move a boat much more efficiently through the water over a Jet drive propulsion system will The Jet drive just waste 40% more horse power . The Krolloras are a good cheap prop type pump as they push a ton of water for the cost

 

Thanks Im on the wright page with that , oh and nice enaligy

 

the overflow is rated for approx 600 gph approx. the inside of the tank can have internal flow either closed loop or powerhead. my internal flow is about 50x/hr. then the skimmer and chiller need a certain gph which isnt part of the equation.

 

So in your 75g reef tank you have 3750 gph from your powerheads.. i was considering buying a couple of hydor koralias (HK for short) for my 40... but couldn't decide which ones.. i was gonna get 2 of the HK 3's for my 40g, but thought maybe the 850 gph that they put out would be too much.. would it be better to go with an HK 3 and an HK 2 (600gph) or should i still get the 2x HK 3's? The HK 3's would give me about 52-53x turnover if I include the 350 gph that the sump pump is putting back into the tank. Too much?