Ideal Turnover Rate

pandaparties · Feb 8, 2021

I want to know everyones thoughts on what a good turnover rate is because I am seeing some wildly conflicting opinions both on here and LFS's. I see so many tanks running setups that are like 10x+ and lots of people saying thats ideal or even higher, but i've also heard from many people that the lower turnover (3x-5x) the better because it gives time for your rock/bacteria to do its thing and properly nitrify and that if your turnover is too hi you wont get proper biological filtration and that your flow should come from powerheads/wavemakers. I'm in the process of getting a 300g built and trying to figure out what my pump rate should be as well as my bulkhead size (animal bean setup)

Mandrew559 · Feb 8, 2021

I have BB 50x turnover

Kazumi · Feb 8, 2021

It seems that the current thinking is 3-5 times through the sump controlled by your return pump, and in-tank "turnover" of around 10 or more controlled by your favorite powerheads.

Back many years ago, I ran 10 times through the sump, as that was the thinking 10+ years ago.

pandaparties · Feb 8, 2021

Kazumi said:
It seems that the current thinking is 3-5 times through the sump controlled by your return pump, and in-tank "turnover" of around 10 or more controlled by your favorite powerheads.

Back many years ago, I ran 10 times through the sump, as that was the thinking 10+ years ago.

See that's what i've been hearing as well and what I was thinking for mine, but then just look at the response above yours and it seems so common on setups here for people to be running 20x+

SPR1968 · Feb 8, 2021

Theres turnover through the sump/filtration systems, and then display circulation

In my large system I have a single Abyzz a200 which turns the water through the sump over around 3-4 x. I don’t want water rushing through the filtration so nice and slow. It also feeds a UVC and reactor so the flows reduced

Now in the display I have 2 MP60s and 1 MP40 on maximum power so they provide a great deal of water movement in the display

I believe the 10x comes from the triton method from memory so it all depends what your trying to achieve

DaneGer21 · Feb 8, 2021

Strictly sump alone I run about 3x.

NeonRabbit221B · Feb 8, 2021

Don't shoot me as I know I am an outlier....

50x turnover in the display from MP40s and 10x turnover in the sump. I have a branch off plumbing to my fuge that is 4x turnover.

zalick · Feb 8, 2021

It really depends on the "type" of flow IMO. On the majority of reefs where our fish and coral live, The ocean tides slowly move in with a little surging back and forth. Then slowly move out. Not anywhere near the velocity we have in our tanks. This is from my personal experience diving reefs all over the world. There are exceptions of course, but those coral walls where you drift dive dont have the same fish...

I prefer to try and mimic this motion, tough as it may be. I've run tanks anywhere from 10x to 100x to achieve this effect.

For my sump, I run between 3x and 4x through it for the reasons @SPR1968 mentioned.

neeper · Feb 28, 2021

I just calculated the turnover rate for my Red Sea Max S-500, it's display to sump turnover is 13.7x.

Why is the main return pump so powerful?

polyppal · Feb 28, 2021

The idea of turnover involving your return pump is pretty outdated. Most reefers these days shoot for 3-5x turnover from the sump to the tank, enough to ensure that heated filtered water is being exchanged efficiently. Going higher than that isnt going to hurt anything, besides making your plumbing louder and costing more. Don't take that return pump GPH into consideration on your actual display tanks flow, (use powerheads for that)

neeper · Feb 28, 2021

oh so 3-5x is like the minimum turnover?

RocketEngineer · Feb 28, 2021

Nope. Just keep in mind that the goal of sump turnover is to exchange enough water between the display and sump to keep water chemistry/temperature the same in both. 1X might do this in some systems, even .5X if the display is big enough. It’s not something that’s set in stone. As long as the two boxes of water have the same chemistry and temperature, it’s enough exchange to do the job.

PBar · Feb 28, 2021

I’m a bit surprised with my own numbers, since I‘m already planning to increase my display flow

Turnover: 2x
Display: 195x

Before anyone asks, no soft coral of course...

Maybe they were soft... after so much flow... they became hard

mike550 · Mar 6, 2021

Newbie follow up question. How do you calculate turnover between tank and sump? For example, I have a 120G tank (let’s say 100G of water). I’m running a Vectra M2 return pump which is currently set at 70%. The max stated flow is 2000GPH. So 70% would be 1400GPH. Do I really have 14X turnover?

I‘m guessing that there’s some flow reduction due to head pressure — but not much.

So do I have too much turnover?

zalick · Mar 6, 2021

mike550 said:
Newbie follow up question. How do you calculate turnover between tank and sump? For example, I have a 120G tank (let’s say 100G of water). I’m running a Vectra M2 return pump which is currently set at 70%. The max stated flow is 2000GPH. So 70% would be 1400GPH. Do I really have 14X turnover?

I‘m guessing that there’s some flow reduction due to head pressure — but not much.

So do I have too much turnover?

I use the flow chart most pump makers provide.

Depends on your goals. I like slower flow through the sump so detritus settles there and I can easily remove it. I'm at about 2x right now (sump + DT vol). So 14x is too much for me, but I know others who run sumps in that range...

X-37B · Mar 6, 2021

In my 120 I run around 300 gph through my sump.
So 3X throughput.
In my display which is mostly sticks I run around 9000gph through 2 constant powerheads and 2 that alternate every 10 seconds for a total of 4 powerheads.
Display flow is around 80X display volume.

JCM · Mar 6, 2021

mike550 said:
Newbie follow up question. How do you calculate turnover between tank and sump? For example, I have a 120G tank (let’s say 100G of water). I’m running a Vectra M2 return pump which is currently set at 70%. The max stated flow is 2000GPH. So 70% would be 1400GPH. Do I really have 14X turnover?

I‘m guessing that there’s some flow reduction due to head pressure — but not much.

So do I have too much turnover?

You lose a significant amount from the head pressure.

mike550 · Mar 6, 2021

JCM said:
You lose a significant amount from the head pressure.

@JCM thanks for that. At first I didn’t think I’d lose a lot but I was able to find a flow/head curve and for 5’ of head it’s around 1400. So even at 70% I’m at 980 gph. So even still I’m around 9-10X for tank turnover.

I guess what I’ve really learned is that if I wanted to turn down my return pump to see if things quiet down I could

JCM · Mar 6, 2021

mike550 said:
@JCM thanks for that. At first I didn’t think I’d lose a lot but I was able to find a flow/head curve and for 5’ of head it’s around 1400. So even at 70% I’m at 980 gph. So even still I’m around 9-10X for tank turnover.

I guess what I’ve really learned is that if I wanted to turn down my return pump to see if things quiet down I could

No problem. 25-50% head loss is normal for home aquariums. If things are too noisy, definitely try turning down the return pump. 9-10x turnover is fine, but so is 3-5x.

BradB · Mar 6, 2021

Many corals have much more flow than we can provide, the water in such a small volume would leave the tank. So enough Tunze powerheads or similar you don't need heaters is probably ideal for them. But then we keep some corals that would just be torn to shreds and animals like clams that just would be ticked. So ideal is the most flow possible that doesn't serious negatively affect what you want to keep. This could be over 100x for an Acropora only tank or under 10x for delicate LPS.