Refugium Design Advice!

Here are my thoughts.... mind you these are just opinions. I read and talked to Tangster and I have always said there is no substitute for experience and he has plenty with refugiums.

I do not understand the role of flow for growing macro algae. Macros take nutrients from the water. A fuge is not a barren field that needs fertilizing. The whole system is recirced constantly even with a low flow fuge. A nitrate concentration is going to be the same in the sump or the display tank. If you flow 1x per hour say in a linear fasion.... then when that water leaves the fuge, it should not have any nutrients in it. Now you have "pure" water.... yet it is only flowing into the DT very slowly.

Now you have a fuge flowing 10x.... well sure the water woun't be "pure" leaving it, but the macro is still going to consume the same amount of nutrients. It is still exposed to the same nitrate concentration and now you know you are not starving the algae at the end of the line. Bottom line is that the amount of macro you can grow is solely dependent on how much nutrients are in the water.... mainly the ones we don't want nitrates and phosphates.

Now if macro was the ONLY way to export N and P thats great.... but it is not, nor is it the macros sole responsibility. The proper amount of live rock denitrifies, the proper DSB denitrifies, proper feeding and so on. I had no nitrates before my fuge and no micro algae. I could barley grow cheato. What I wanted it for is to mop up any nitrates and P that were left over. Since it was nitrate starved I doubt it was uptaking much P. I started using bio pellets at the end and fully expected the cheato to die out.

I guess my point is that it was never my goal to grow bushells of macro in a week. My goal was to do everything I could to lower nitrates w/ LR, DSB, and feeding and have the macro soak up the rest.

 

ya, there's more... If all you want to do is grow macro algae, great. But a fuge is much much more. I wanted a fuge for it's primary role of growing pods free from predation. I wanted a DSB to denitrify and support micro fauna. As far as flow in a refugium for pods and DSBs... well, they do not need a river. You want a tranquil place for pods to thrive where they do not have to hold on for dear life.

A DSB needs proper maintenance. It is not static, it is live. Worms, stars, micro fauna and pods all do their job to keep it tilled and clean. Bacteria does the rest completing the nitrogen cycle and releasing N2. If you feed too much raw water to it and choke it out with a layer of ditritus, then it will die. It needs to be fed a flow rate of "junk" that it can process.

So I was going to start off with a very slow flow but picked it up. My thinking was that I didn't care about the macro, but I did not want to inundate my fuge with too much ditritus. I probably had about 8x fuge volume per hour and my bed was nice and clean...dirty but clean with lots of worms and life.

My fear was that the very slow flow rate would bring less detritus to it, but at very low flow the fuge turns into a settling tank and everything that enters sinks to the bottom. My water was very slow moving in my fuge, but you could at least see things moving through and settling. Now perhaps Tangster has sucsses with this and I underestimate how much crap a DSB can process.

For you... seems like you need to figure out what you primarily want out of your fuge. You do not need a 100g tank to grow macro. All you need is a little box and a light. If you want a remote deep sand bed away from the DT then that is a good start. If you have plenty of sand in the DT and LR and you want another 6 square feet of DSB, you will be removing a lot of nitrates. But you can also do a remote DSB much easier with a 5 gallon bucket. But I also wanted a bigger refugium to host a bunch of stuff not just pods and macros.

I'm no fan of Miracle Mud. Never been much for expensive snake oils and magic potions. But hey, to each his own. My only question is where does your raw water from the DT enter the filter system? I would try to split my drains and feed the fuge and skimmer section independently. I would put the overflow from the fuge to the return section and straight up to the DT. Splitting flow from the return pump to feed the frag tank. It can overflow to anything. You have two pumps and you could use just one to supply everything.

 

+1;d

 

Powerman makes a lot of good points, K+ to you. IMPO everyone needs to look at what they read or are told and decide what they are wanting their outcome to be and go from there. It should be a general starting point or guide so to speak. Every tank is different and what works for others or myself may not work for you (or not as well). There are a lot of variables that will play into the flow, lighting schedule, temperatures,....etc on your tank and you will have to play with these until you get your tank happy.

These are MY thoughts on MY fuge.
1st: I want a place for pod production
2nd: My thought on nutrient export is the slower the flow through the fuge the more time the Chaeto has to extract the nutrients from the water column (Just my thoughts).
3rd: I want all the nasty algaes to grow in the fuge and not in my tank (hence slower flow).
4th: as far as flow goes, my fuge is around 15 gallons and right now I am flowing around 125-150 gph.

There are a lot of different ways to accomplish the same things and you will need to decide what will work the best for you.

As far as the plumbing goes I would split feed the fuge/sump with valves so you could regulate the flow to the sump or fuge and make adjustments as needed.

 

Same to you yamaharider. Good points. That is what was so baffling to me about this hobby. It is not a cookie cutter hobby where you put A, B, and C together and come up with D. One person can put two exact systems together and each will be different.

All we can do is read and research and come up with a good starting point for our individual cases. After that what is achieved is completely up to how good the individual can maintain their system and how well they understand the processes taking place. No end to this hobby that is for sure. It's pretty cool when you see a thriving system though.

 

And strictly for discussion... To me, all macro does is absorb compounds from the water. It does not seem to matter how fast the water is moving...cause around the algae in the fuge the velocity isn't that much faster... at least to me. Where as plenty of research has been done to what actual flows are ideal for corals to capture food. Too fast and they can't grab it and too little they do not get enough food or respiration.

Yet there is the other school of thought that firmly belives that cheato needs vigourous flow and needs to tumble. I have read plenty that people can't grow cheato.... they always chime in and tell them to speed up flow and put in a deflector arrangement to shoot the incoming water across the surface to tumble the cheato. When they do that, they all grow much more cheato.

So if that is true, then what I belive is wrong. That in my case of cheato not growing well was not because it was nutrient starved but because it did not have proper conditions. And that I could indeed export more nutrients in an easier method of just throwing away some cheato.

Either way, I don't care. The end result was to lower nitrates, so SPS could thrive and not be choked by micro algae. I had zero nitrates, no micro algae in my DT, healthy thriving SPS, and very little cheato growth. Mission accomplished. Does not really matter what gets the credit between LR, DSB, cheato, GFO, or bio pellets.

 

I can agree with that. My cheato has been growing extremely fast. I have been removing a big handful every week. For quite a few months I neglected my tank due to work related circumstances. My son and my wife basicaly fed the fish and kept the tank topped off. During this time my RODI filters went bad and I didnt catch it. My TDS in my topoff water was at 38. I have been battleing GHA for a few months now and have been slowly winning. I dont really care how much cheato grows as long as I dont have neusience algea and the tank is happy.

 

And to screw things up even further, throw in some Mangroves. Many people grow Mangroves and cheato. Seems to me they do the same job. Although seems Mangroves can take up more than just N and P better than cheato.

Yet many will tell you Mangroves need tons of flow.... why? What is different between Mangroves and Macros? And if your goal is to grow Mangroves, then that seems counter productive to having a nice fuge for pods and a sand bed since they require a grat deal of flow. They are both plants, so how is nutrient uptake different between the two?

Seems like anything between a stagnant pool and a raging river will be fine.

 

I understand what your saying except for the pure water part. To me the water should be the same if the same amount of N and P got absorbed.

I will have very little Live rock in this system. As much as i can fit in the sump (hopefully 60 to 80 lbs) and DT will have 30 to 40 lbs.

I too am trying to grow cheato for N and P export as well.

From my experience with slow flow fuge there are a couple things i don't like:

1) If water comes from the DT and you don't have a filter sock on entry too much detritus settles instead of being removed from the system. Even if a DSB will eventually break it down i think its more efficient to just remove the detritus instead of letting it settle.

2) Detritus will get stuck in the cheato. When i shake my cheato every couple weeks the whole fuge is clouded.

3) Algae can grow on the cheato. I dont mind algae growing on the glass but starving the cheato is not good. Although algae growing on cheato is still better then it growing in the DT.

4) If algae or detritus accumulate in cheato or in fuge in general it is harder to get out. When i shake the chaeto all the detritus algae growing on it etc... Sinks to the bottom and stays in the fuge. With higher flow it can quickly be removed.

IMO cheato is better off with higher flow so it stays clean and detritus free with no algae choking it off.

I think that its better to physically remove as much detritus as possible and let the Live Rock DSB etc... do the job on what you cant remove.

 

I just meant that say your ball of cheato can consume 100 "units" per hour of N and P, and your water has a concentration of 100 units per gallon..... then if you put one gallon per hour through your fuge, it should be clean coming out. Now increase flow to 10 gallons per hour. You have a total of 1000 units available minus the 100 and you are left with 90 units coming out of the fuge every minute. Bottom line is the fuge is attached to the system and the water is circulated and the cheato will consume what it can.

Well here is one of the "important" point left unsaid in these types of exchanges. On my 90g system I was moving about 650 gph through my overflow. I split my drains though to supply my skimmer and fuge independently. Many people run fuges and sumps in series.

So I had about 100gph going through my 15g fuge, and the rest going to my skimmer and I had a very good skimmer. No mechanical filters of any kind any where. So my fuge seemed to be fine with what I gave it and I skimmed out most of the other crap agressively. So overall I did not have a lot of ditritus build up anywhere cause I had very good flow everywhere.


To really screw you up, since you want to do a minimal live rock system, have you looked into algae scrubbers. Very very interesting and seem to much better at exporting N and P. Especially since the majority of that will not be done by rock for you.