47G SPS...Revamp

[M007]

Hey guys, sorry for adding to the detraction of the thread . I do have a question however, as I like the idea of having Siporax in my sump as opposed to Live Rock for 2 reasons: it's "neater" than LR, and it will allow more space for a rediculously over-sized skimmer.

You mention a volumetric flow rate through the bacteria (100 gph, I think) but that's only good for a set area. For instance, 100gph through a 6 in diameter reactor let's say, is much different than flow through a 10 in diameter reactor. I think what we really need is an effective velocity over the media, which could be converted and applied to any reactor or chamber.

Am I on the wrong track here? Perhaps we should start a separate thread?

Might take some digging, check out Aug 2012 TOTM.

 

[sahin]

Hey guys, keep the discussion going. None of you ever need to apologise. I've been sooo busy this weekend its unreal. I'll catch up on the thread and discussions during the week.

 

[Reefvet]

I think what we really need is an effective velocity over the media, which could be converted and applied to any reactor or chamber.

Flow through the media is exactly what I'm referring to. The effective flow needs to be 100 gph minimum to support ideal aerobic and anaerobic bacteria colonizing.

To monitor this you measure the outflow. In the lab we have flow measuring gates. In the practical application of a home reef tank you'd simply do a calibration by measuring the outflow into a container for a set period of time and calculate when you have the volume you need +10% for error, or more depending on your situation. You can nearly double the flow before you start to loose the anaerobic component.

I run all my lab and home systems on enterprise grade UPS which have automatic voltage regulation and produce a true sine wave so that I don't have any variation. In research that's called a control. At home I call it peace of mind. :idea:

 

[Reefvet]

... check out Aug 2012 TOTM.

That's similar to what I run.

I like this setup.

And this is a good practical test of Siporax vs similar media.

 

[Novice101]

That's similar to what I run.

I like this setup.

And this is a good practical test of Siporax vs similar media.

Those are both mind blowing but what is the bottom video telling us? Is the first one on the left have less surface hence why it held more of the ink?

 

[Reefvet]

Those are both mind blowing but what is the bottom video telling us? Is the first one on the left have less surface hence why it held more of the ink?

Siporax vs two knockoff medias. Siporax being many times as absorbent/adsorbent so it immediately takes in the liquid while the others are very slow to the same.

 

[naterealbig]

Reefvet, I'm sorry, but I still don't understand the logic. Gph is not the way to measure nutrient dwell time in the media - velocity is. What you are telling me is that if I filled up a 1000 gallon reactor with media, that the optimal flow rate is 100gph. The water would be moving so slow through the reactor, that you could not reach peak denitrification. For your tests, you were able to determine an optimal volumetric flow rate, assuming you used identical reactors for all of your tests. The volumetric flow rate will vary however, as the diameter of the reactor (cross sectional area) changes. Perhaps it would just be easier to ask you the dimensions of the container you were using for the tests?

 

[naterealbig]

I'm actually looking to purchase some of this, also. What volume ( or weight, if that's a better unit of measure) would one need for a heavily stocked 180g aquarium, assuming no other means of biological filtration? I found some vendors on the UK fleabay that will ship to the US. Any watch outs here? Thanks!

 

[rovster]

Great pics Sahin, and great discussion. I too have pondered adding some bio media for some time but have been hesitant. Just a general question for you or reefvet, would this media benefit from an occasional or even daily stir to free up all the crap, like zeo recommends. Part of me thinks it's best left undisturbed, and part of me thinks breaking up all the crap and bacteria would give the skimmer more to pull and possibly food for corals? It would also prevent from too much crap building up, although not sure if that is even an issue.

 

[Reefvet]

For your tests, you were able to determine an optimal volumetric flow rate, assuming you used identical reactors for all of your tests. The volumetric flow rate will vary however, as the diameter of the reactor (cross sectional area) changes. Perhaps it would just be easier to ask you the dimensions of the container you were using for the tests?

You're making some assumptions here that are not correct. The media varies in size and therefore volume so you can't use the same size media reactors unless you then allow for initial boundary effects and turbulent flow.

In order to really measure flow you would have to do a computational fluid dynamic analysis or model it using Navier-Stokes formulations.

Since nutrient levels are going to vary the fluid dynamics simply can't be 100% accurate.

I'm sorry, but I still don't understand the logic. Gph is not the way to measure nutrient dwell time in the media - velocity is.

I wasn't looking for optimal nutrient dwell time or peak denitrification. I was looking for a rate of flow that kept anaerobic denitrification effective on the media. Anaerobic process is supported inside the porous media by aerobic process at the surface.

I've converted my results to a rough guideline and GPH is the number these guys have available.

I'm trying to relate how to use this media in the average reef aquarium as an adjunct to a primary system of live rock so I'm keeping the numbers simple. Nobody here is going to have the means to measure flow. They're going to estimate it from the rating of their return pump or the pump feeding a reactor off their sump.

I used 1 litre media reactors for all media. They were built out of 6" diameter acrylic and have a 3/4" inlet at the top and a 3/4" outlet at the bottom. The length of the acrylic reactor was adjusted to each media so that it held 1 litre of that specific media.

 

[Reefvet]

Part of me thinks it's best left undisturbed, and part of me thinks breaking up all the crap and bacteria would give the skimmer more to pull and possibly food for corals?

You don't want any significant build up on the surface of the media. Run it after a filter sock or sponge and keep those clean. It's very simple stuff to maintain and it does not need to be replaced.

 

[Reefvet]

dbl post. Mods please remove

 

[rovster]

Siporax vs two knockoff medias. Siporax being many times as absorbent/adsorbent so it immediately takes in the liquid while the others are very slow to the same.

You don't want any significant build up on the surface of the media. Run it after a filter sock or sponge and keep those clean. It's very simple stuff to maintain and it does not need to be replaced.

I get that part but I don't run socks full time, I run them maybe 30-40% of the time around waterchange time. Assuming you wanted to go sock less how often would the media need to be cleared? I'm assuming too frequently and you'd be messing with the anaerobic process. Also with carbon dosing some slime buildup may be unavoidable. I imaging that might get pretty gunked up.

I'll just get right to it. When I first set up my system got 2 reactors one for carbon and one for Gfo. The carbon one has sat unused for a year since I run carbon passively in a bag. I always thought of bringing that second reactor online with bio media. It's a large way too big of s reactor for my system but may be perfect for this application.

Now this is a derail! Sorry Sahin, you'll need to post more pics to get this thread back on track lol....

 

[naterealbig]

You're making some assumptions here that are not correct. The media varies in size and therefore volume so you can't use the same size media reactors unless you then allow for initial boundary effects and turbulent flow.

In order to really measure flow you would have to do a computational fluid dynamic analysis or model it using Navier-Stokes formulations.

Since nutrient levels are going to vary the fluid dynamics simply can't be 100% accurate.

I wasn't looking for optimal nutrient dwell time or peak denitrification. I was looking for a rate of flow that kept anaerobic denitrification effective on the media. Anaerobic process is supported inside the porous media by aerobic process at the surface.

I've converted my results to a rough guideline and GPH is the number these guys have available.

I'm trying to relate how to use this media in the average reef aquarium as an adjunct to a primary system of live rock so I'm keeping the numbers simple. Nobody here is going to have the means to measure flow. They're going to estimate it from the rating of their return pump or the pump feeding a reactor off their sump.

I used 1 litre media reactors for all media. They were built out of 6" diameter acrylic and have a 3/4" inlet at the top and a 3/4" outlet at the bottom. The length of the acrylic reactor was adjusted to each media so that it held 1 litre of that specific media.

Hi Reefvet,

You are right, a detailed analysis of the fluid dynamics would be far too complicated (I took the class a couple years ago, and this is way beyond anything we covered there!). Really I was just looking to find an average fluid velocity over the media inside the reactor, as the volumetric flow rate (100 gph) is only valid for the diameter reactor you used.

In this instance: Volumetric Flow Rate = velocity * cross-sectional area
V = v*A => v = V/A
V = 100 gph
1 gallon =~ 231 in^3 => V = 100*231 in^3/hr = 23100 in^3/hr
A = pi*r^2 = 3.1415*6^2 = 113.1 in^2
=> v = velocity = (23100 in^3/hr)/(113.1 in^2) = 204.25 in/hr

Using the original Volumetric flow rate equation (for anyone that cares ):
For a 4" diameter reactor:V = (204.25 in/hr)*pi*r^2 = 204.25*3.1415*4^2 = 44.44 gph (after converting cubic inches to gallons)

Similarly, for a 6" diameter reactor: 100 gph (as you stated from your tests)

Similarly, for a 8" diameter reactor: 178 gph

Similarly, for a 10" diameter reactor: 278 gph

While these theoretical flow rates are likely only "accurate" for a particular media height within a vessel, it illustrates the marked difference between required flow rates that might be required within different sized reactors.

Thanks so much for offering the information, along with your test results. You are absolutely right, the Siporax is pretty expensive from the European sites. Based on the results you mentioned, I will go with several liters (Seachem recommends 1/2 a Liter of Matrix per 50 gallons of tank water) of Seachem's Matrix (At double their recommendation).

 

[naterealbig]

For anyone interested in the math, I made a mistake in the calculation. I entered the diameter of the vessel instead of the radius, as the equation calls for. My mistake just happened to cancel itself out, so the volumetric flow rates for different sized reactors are accurate. But:

A = pi*r^2 = 3.1415*3^2 = 28.3 in^2

v = velocity = (23100 in^3/hr)/(28.3 in^2) = 816.3 in/hr (not 204.25 in/hr as stated above)

 

[Reefvet]

Assuming you wanted to go sock less how often would the media need to be cleared?

You can just rinse the media and shake it a bit, but do it in saltwater. Surface aerobic bacteria and in the water column and will re-populate the surface quickly. The really useful anaerobic bacteria are in the pores of the media.

 

[Reefvet]

Hi Reefvet,

You are right, a detailed analysis of the fluid dynamics would be far too complicated (I took the class a couple years ago, and this is way beyond anything we covered there!).

That's my point. Simple numbers are close enough here. I taught that material for 20+ years but we're going to bore these guys to tears if we don't see some pretty pictures of coral soon.

Here's a quick iPhone comp of my latest research subjects. Aussies just in from the wild a couple of weeks ago.

 

[naterealbig]

Sorry - dp

 

[naterealbig]

That's my point. Simple numbers are close enough here. I taught that material for 20+ years but we're going to bore these guys to tears if we don't see some pretty pictures of coral soon.

Here's a quick iPhone comp of my latest research subjects. Aussies just in from the wild a couple of weeks ago.

Fair enough. Those are some beautiful corals - wish I got to play with those all day. Instead I make soda for a living

 

[biggles]

Right, i'm going to get two of the 2L Seachem Matrix bottles of rocks and work out a good water flow system that follows the suggested guidelines you guys have been discussing. Thanks for the great info :thumbsup: