Flow Rate Through My Sump

[mcgyvr]

And then your first post, which talks about the flow through the sump being too fast to process. I call B.S. on that one.

Poor wording on my part..
Faster than it can process it "all" was my intention..

Just meant its moving faster that it can process the entire volume of water being transferred past..

 

[DesertReefT4r]

I totally can see and understand the logic behind both low and high sump flow. What I have done on my setups for sump return pumps is to take the display gallons multiply by 10 and find a pump rated at about that gph range, then after head loss I figure I end up with around 5-7x turn over in the sump. This is what I have done and it has worked for me and this is for a sump located in a stand with under the 5ft head height. Obviously this would not work with a remote sump.

 

[ca1ore]

I don't believe flow rate has much effect at all over how efficient the protein skimmer is.

I'm totally with you - been arguing it for years. If matching flow rate to skimmer was important, recirculating units wouldn't work :lol:

 

[ca1ore]

The skimmer is most efficient the dirtier the water its in. The faster the flow through the sump the dirtier the water in the skimmer section will be.

And you 'know' these things, how? Or you just 'think' they are. I don't actually think either is true

The question then is how fast does the skimmer remove proteins from the water and at 3x vs 5x vs 10x is there a significant difference in the protein content in the skimmer section at steady state. My guess is that it would be insignificant.

This has long been my argument about why water flow through the sump has no relationship to the amount of water the skimmer can ingest. Even the best pass though skimmer does not skim all of the removable proteins in just a single pass (which is why recirculating skimmers exist). It's easy to observe that this is the case. Even if we could suspend fluid dynamics for a moment, and have 100% of the overflowed water run through the skimmer, the output water would still contain some removable proteins. Since we cannot suspend fluid dynamics, the reality is that some water in the sump never gets processed and some gets processed multiple times. I'd argue that at 10x the latter is less likely, but it still happens; so unless you believe that you skimmer magically removes everything in just one pass, that extra flow really gains you very little.

 

[Frogmanx82]

And you 'know' these things, how? Or you just 'think' they are. I don't actually think either is true

This seems obvious to me but maybe I'm missing something. For sure the skimmer is taking stuff out of the water and every system I've ever seen for cleaning and removing material from one place and moving it to another does so at a higher rate the higher the concentration of contaminants are. With no flow the protein skimmer would eventually scrub the skimmer section and there would be little to skim out. Poor efficiency.

At very high flow, the skimmer compartment is at the same contaminant level as the whole tank. So the only issue for the skimmer efficiency is whether the skimmer section has enough flow that the contaminant level isn't noticeably less than the rest of the system. I would bet it doesn't take much flow to accomplish that but I've never calculated what that rate would need to be.

Certainly the higher flow isn't going to hurt the skimmer and having a higher flow through the sump than the skimmer pump isn't an issue. It's not going to make the skimmer less efficient.

 

[mcgyvr]

My whole point is that if I'm just passing water through a sump at a rate higher than the filtration system can process it is just using more electricity than needed...
Not sure how that one is up for debate..

Maybe I'm just misunderstanding or not following frogmanx/ca1ore's points here..
I was never talking about making a skimmer less or more efficient.. At the rates we are discussing here the effect on the actual efficiency of the skimmer is so minimal its not even worth talking about..

But the electricity savings of running a sump at 2x vs 10x can be quite substantial..

I'm quickly seeing this post.. like the ones before it will really get nowhere.. so it was fun.. but thats it for me..

 

[Frogmanx82]

Well it’s been interesting for me because I’m reevaluating how much flow I really need. Fortunately I have a dc pump and am thinking about dialing back from the roughly 400 gph on a 90 gallon tank. 2x is probably plenty.

 

[mitch91175]

The skimmer is most efficient the dirtier the water its in. The faster the flow through the sump the dirtier the water in the skimmer section will be. The question then is how fast does the skimmer remove proteins from the water and at 3x vs 5x vs 10x is there a significant difference in the protein content in the skimmer section at steady state. My guess is that it would be insignificant.

For me I like to run less water as it keeps the whole system less stressed so 3x is good for me and I just adjust the skimmer to get a good skimmate. Matching flow rates to me is a useless exercise.

Feel the same way. When I plumbed my setup I didn't think one bit about head loss, angles, etc. I plumbed my setup with what I thought was best to maximize space under the aquarium. I then just purchased a return pump that I felt was the best for me and that had a good rated GPH and called it a day. I did go higher on the GPH simply because I use my return to feed a manifold with 3 outlets. That was the only reason I personally worried about flow rate/GPH. I do not even measure the amount of flow going through the reactors (at the moment). I just adjusted each outlet on the manifold to what looked like a good rate based on how the media tumbles in the reactor.

 

[gabe145]

I know with coral tanks there is the saying of 10 times the tank capacity. Yet, with FOWLR I am not sure if you'd want less.

 

[Frogmanx82]

I know with coral tanks there is the saying of 10 times the tank capacity. Yet, with FOWLR I am not sure if you'd want less.

That 10x number is flow accomplished by something like a koralia water fan. Not really a pump.

 

[Trigger Tough]

That 10x number is flow accomplished by something like a koralia water fan. Not really a pump.

My MP40 provides the flow in the tank, that's why the return pump can be adjusted as low as I want

 

[Trigger Tough]

^^^That was for gabe145

 

[rhinonm]

I run a high 3k-3.5k gph (dct 15000, 4000 gph) through 2 x 1" returns @ 200 gallons. I like higher sump turnover for 3 reasons. Helps filter more water through filter socks, on cold nights keeps tank warm (heater in sump), and it adds to overall flow of the aquarium.

I agree though, it doesn't help skimmer performance.