Flowrate VS Turnover Rate

[jem]

If Turnover Rate (Slow Return Pump) is very slow,

can i use internal tank flowrate as a replacement?

[kareen]

What is this "turnover rate" means to your tank? Do you have a sump connected to it?

I'll think that with a low turnover rate, the "full cleansing power " of the sump is not realise.... and also note that with that extra area, it also provide bigger surface area for oxygen exchange.... to pack more corals and fishs in that little area....

There is nothing wrong with a lower turnover rate if you know the effects and from your judgement, the tank residents made no complains

[jem]

thanks for the input.

its something like..

Main Tank > Overflow > Sump > Return Pump > Main Tank > Overflow [ Turnover Rate ]

My turnover rate is very very slow..

500L/H

[Achilles Tang]

The flowrate in the main tank can be very high.... you can put in like 20 Tunze streams + seaswirls + wavebox to create a crazy whirlpool but if your tunrover over from main tank to sump is very low (where your mechanical filtration is eg skimmer), its extremely pointless.

It's like a public toilet or smoking lounge with a very tiny hole for ventilation.... how do you expect the smell to escape and fresh air to be come in?

[kareen]

thanks for the input.

its something like..

Main Tank > Overflow > Sump > Return Pump > Main Tank > Overflow [ Turnover Rate ]

My turnover rate is very very slow..

500L/H

What Achilles says is right.... apart from the 500l/h, what is the display tank volume? [Assume sump is solely for "cleaning up water"]

500l/h turnover in a 150l display tank is alright in my IMHO 'cos it has about 3x the rate although higher rate has better cleaning power when equip with the correct equipment.

[kareen]

BTW, what you intend to keep play a part in the decision making too.... For example, in a sps tank, it is advisable to have higher turnover rate.

[thomas_lim]

What AT said is very true. We always got mixed-up on turnover for flowrate. And to make matter worst, we tend to reduce the operations cost by add lots of small wave maker in the main tank instead of operating a high power return or more costly return pump.

I admit i'm 1 of them who kept repeating the same mistake

[cdckjn]

if your turnover rate is so fast, then it will create some sort of flowrate within the main display tank. In my opinion, it is best to be over-the-top with the turnover rate and then to prevent "dead corners" within the display tank - to have wavemakers to stir up the water.

[tineng]

turn over and flow rate are in someway related, but they are for totally different issues.....for sps you need high flow, lps mid to high and softie maybe low....

for turn over, it usually mean the water movement between sump/filter and the main tank...this really depends on the equipment that you have in your sump....too slow and you might not be able to properly process the junk in the main tank, too fast and you might not have enough time to process the junk that pass through it.....

so really, i don't see how increasing the flow rate is compensating the low turnover....

even the topic of flowrate and turn over can be complicated and should not be judge by a single number....point a 800 l/h pump directly at a sps, it will be gone in days....if sps is in a canyon blocking the flow then even a 20000 l/h tunze blowing might also be useless....you shouldn't be too bother by these numerical things, but should instead focus on the condiftion of your corals and how they are affected by the various 'numbers'....

[kareen]

In my understanding.... turnover rate and flow rate are different topics although they are measured in the same term, l/hr.

- Turnover rate means how fast the volume of water that is been "exchange".

- Flow rate means that how fast the flow of water is travelling.

Can you guys see the differences? The function of the turnover rate and flow rate? Turnover rate is a part of the "clean up function" in a tank-sump tank design... Flow rate is an indication of the "stimulated wave" in our aquarium.

PS: it is always better to have a higher specification... eg. higher return pump and higher skimmer pump, etc... But the bottomline is cost especially the running cost as pumps runs 24/7. If that is within your buget then by all means....

[johntanjm]

Yeah I agree with everybody with the way you distinguish between flow and turnover rate. One point to add is given the xx L/Hr, you'll also need to take into consideration tank volume. Once I had a 100L tank and I had a turnover of 2600L/Hr. dividing 2600 by 100 will mean that within an hour, every molecule of water in my tank goes through the filtration an average of 26 times.

The bigger the tank, the more difficult it'd be to achieve good turnover. I asked around and I think alot of folks have their turnovers between 10-15 times in a hour.

In my opinion, turnover rate is very impt as it means how frequently our filtration is being utilized.

Recently I've also come to notice a different approach. People put wavemakers in both display and sump tank so they both have flow going through themselves. then they just use a single pump to exchange water between the 2. by the principle of diffusion, this will have quite an effective filtration effect too and also it is very energy efficient. I'm still trying to figure out if there's any loop hole in this logic.