Fuge Flow

I personally prefer a low flow through the fuge. As 2in10 said It allows a higher dwell time, detritus is being sent to the fuge and not disturbed and sent to other parts of the tank this way.

 

I have planned for a little less than 10x flow through my sump. Which has three sections, a skimmer, fuge and return. So it will be 10x flow through the fuge.

 

The way I se it is that my tank has plenty of pods and like it or not GHA & calurpa (illegal for sale here but came in on LR), my tak has 32xthe flow rate so a fuge need not be so low of f low. The macro and pods will only consume wate a aa given rate weather or not the flow is low or high, but it seems that a higher flow rate might keep it cleaner and healthier. Not that I'd run the fuge with 32xan flow but perhaaps up to20, though I'm sure I'll end up w/10 to 15x.

 

So no rock at all? The rock will start off as dead rock.

 

There is simply no point. If you have a DSB then you want it to have circulation. LR rubble just chokes it. It becomes a detritus trap due to reduced flow in the fuge. Detritus settles out in the rock choking the DSB below, not to mention the rock sitting on it. Pods do not need it for habitat. The DSB has plenty of micro fauna and algae is enough for pods. As far as contributing to the bio filter... it would have very little effect, just because it too gets choked with detritus... which then gives you something else you must clean in your system.

 

But again, dwell time is irrelevant if the uptake of nutrients is the same. Clean water in small amounts is the same as not so clean in larger amounts... the total nutrient export does not change.

As far as settling... well if that is all you want you can just make a settling chamber and everything would settle out for you to vacuum up.

I'm not trying to knock one thing or the other... but we do things for a reason, if there is no reason, then why do it? There is a side of the debate that believes in very low flow, but I have not heard a solid reason for it, or what it is I am doing better over a high flow.... same for high flow. I have not heard a solid reason of things I am accomplishing with high that I can't do with low.

As far as macro growing better... seems that algae does like high flow, just look at over flow boxes, or by powerheads. Algae turf scrubbers are trying to achieve very high flows... seems what that is accomplishing isn't nutrient supply, but improved respiration. The exchange of gases is much better and the algae grows faster... faster growth means more nutrient export. But in those case you want high localized flow at the algae... not just high volume of flow around the algae. A ball of cheato needs it in the inside too... so people tumble cheato, or make ATS for that reason... however, you are not going to achieve that just moving 40x fuge volume an hours... or rather there is better ways of doing that than moving huge volumes of water.

Now if there is some mechanism that gives me better results by reducing flows significantly, then I am all ears.

 

Look at mine here Powerman and please tell me what the problem is. This is a HOB refuge/skimmer combo. I have a DSB with LR and cheato but I thought a refuge was suppose to have LR. IMG_2181 | Flickr - Photo Sharing!

 

Don't think of it like that... I don't want to tell you you are "wrong". There are those with LR rubble in their fuge... is it the end of the world, no? Can they have a healthy system.. sure. But can you tell me what the point is... is there a reason? I honestly don't know where the thought came from that you have to put LR rubble in a fuge.

First do you see how much poo is accumulated... that needs to be cleaned. For a DSB to work, it needs the top layer to have oxygen... waste gets processed down, and eventually all the oxygen gets used up... or most of it and the bed become anoxic where other bacteria live and convert nitrates to nitrogen gas where it bubbles up and out of your tank. If the bed has no circulation and oxygen to break the waste down in the first place, then that does not work.

The rocks are simply taking up surface area for the micro fauna to process waste. So you are taking up vital surface area from the DSB and not allowing it to do it's job for which you placed it there in the first place for.

If anything... build a rack to keep the rock off the DSB. That way you can even make it easy and take the rack out and clean the rocks... at least it keeps a water flow across the bed.

And with any fuge, flow is going to be an issue.... so besides all the debate above which is better... if you are sending too much water to it and too much poo is settling out and accumulating... then you need to give it less water so it can process the amount that goes in... OR.. you need to filter the water a bit to catch some of it so it does not just pile up. Of course it always settled in my sump, but it was easy to clean it out there every couple of weeks. You can't just let your fuge pile up with detritus.