Skimmer chamber flow .

[davidm777]

Hello,
Trying to understand this to play with the possiblities. In a reef conversation it was said that the more flow you have from your display to the sump the better. Go as far as your return will allow you.
I have a 20gal display with a 30ish gall sump on a vectra s2, I was running at 30%. After the conversation I went up to 80% on the vectra.
My only filtration is a skimmer (Tiunze 9400DC). I have some live rock on the sump but that's there just because. With the increased flow I noticed my skimmer started not working as well. It's wierd but even though have no filtration the diplay seemed to look better, hard to explain.
Anyway the increased flow decreased the skimmer efficiency. I always wanted to put an oversized skmmer but heard that it was better a smaller skimmer propelry tuned. Now I am just wondering. Can I oversize the skimmer and increase the flow?
Is there any information available regarding the flow on skimmer chamber, the only thing I found was some old forums with this questions but nothing deep.
Any thoughts?

 

[Fish Fan]

My first thought is that I disagree with whoever told you that you need to crank up your return pump as high as it can go. Typically, flow through the sump can be as little as 3x to 5x the tank volume. Flow is important in reefkeeping, but flow in the tank is achieved typically with circulation pumps and powerheads, not just from the return.

I hope that helps!

 

[penfold2]

With regard to skimming, the only advantage to increasing sump flow is to ensure that only dirty display water is passing through the skimmer. As long as your sump flow is greater than your skimmer flow, and the skimmer output is downflow from the intake, none of the skimmer output will flow back to the skimmer intake, and the skimmer will always be processing the dirtiest water possible.

I don't know why increasing your sump flow would decrease skimmer performance. Maybe a coincidence with some other factor? It could make your tank look better if the increased flow in your display is carrying more detritus into your overflow, but that would be better achieved with powerheads than a bigger return pump.

I don't think running an oversized skimmer with increased sump flow will be beneficial, as the whole point of skimmer sizing is to maximize efficiency. An oversized skimmer may have trouble producing a strong foam head, which could lead to producing less skimmate than a properly sized skimmer.

 

[Dan_P]

Hello,
Trying to understand this to play with the possiblities. In a reef conversation it was said that the more flow you have from your display to the sump the better. Go as far as your return will allow you.
I have a 20gal display with a 30ish gall sump on a vectra s2, I was running at 30%. After the conversation I went up to 80% on the vectra.
My only filtration is a skimmer (Tiunze 9400DC). I have some live rock on the sump but that's there just because. With the increased flow I noticed my skimmer started not working as well. It's wierd but even though have no filtration the diplay seemed to look better, hard to explain.
Anyway the increased flow decreased the skimmer efficiency. I always wanted to put an oversized skmmer but heard that it was better a smaller skimmer propelry tuned. Now I am just wondering. Can I oversize the skimmer and increase the flow?
Is there any information available regarding the flow on skimmer chamber, the only thing I found was some old forums with this questions but nothing deep.
Any thoughts?

Increasing the flow to the sump might have changed the nature of the organic matter in the sump. A higher flow stirred things up, but I can’t decide which way this would push skimming. More flow supplies more oxygen to the sump, possibly enabling faster bacteria growth and the digestion of organic matter which could mean less bubble forming material. This is all off the cuff hypothesizing.

As for more vs less flow, a very low flow would allow the skimmer to deplete the water of skimmable material, tesulting in under skimming the system’s water. A fast flow just means the sump water is identical to the aquarium water. High flow coud be a waste of energy.

 

[davidm777]

My first thought is that I disagree with whoever told you that you need to crank up your return pump as high as it can go. Typically, flow through the sump can be as little as 3x to 5x the tank volume. Flow is important in reefkeeping, but flow in the tank is achieved typically with circulation pumps and powerheads, not just from the return.

I hope that helps!

I remember this 3x-5x rule from Jake Adams on the Overdoing session of reef theraphy. Thanks for the reminder.

I don't know why increasing your sump flow would decrease skimmer performance. Maybe a coincidence with some other factor?

I know it was the only change, since it was an experiment I made sure of doing one thing at the time. A quick AI search says that skimmer work on "Time of contact" wich it was probably why the increased flow reduced the efficiency... but I do not trust AI blindly which is why I came here.

High flow coud be a waste of energy.

That is what I am thinking. I am just suprisded you guys not experienced less efficiency on the skimmate based on increased water flow since it was my experience.

 

[Dan_P]

I remember this 3x-5x rule from Jake Adams on the Overdoing session of reef theraphy. Thanks for the reminder.

I know it was the only change, since it was an experiment I made sure of doing one thing at the time. A quick AI search says that skimmer work on "Time of contact" wich it was probably why the increased flow reduced the efficiency... but I do not trust AI blindly which is why I came here.


That is what I am thinking. I am just suprisded you guys not experienced less efficiency on the skimmate based on increased water flow since it was my experience.

What you are experiencing as decreased efficiency might be specific to your setup, not an observation of how skimmers work.

 

[penfold2]

A quick AI search says that skimmer work on "Time of contact" wich it was probably why the increased flow reduced the efficiency... but I do not trust AI blindly which is why I came here.

The contact time refers to the flow through the skimmer, not past it. Contact time can be altered by changing the flowrate of the skimmer pump, but not the return pump.