Adding sand to an existing refugium

[BlackLagoon]

I have a refugium that's been established for about 2.5 years. I have about 1.5 inches of fine sand, some live rock, and Cheato. I would like to turn it into a deep sand bed refugium. I would eventually like to have about a 6" sand bed. I've done some research on Dr. Ron Shimek's website, he seems to be the authority on DSB's. My plan is to use sugar fine aragonite sand (dry), and add it to the top of my existing sand bed. Dr. Shimek says to add the new sand an inch at a time, but he doesn't say how long to wait before adding the next one inch layer. The wait time is to give the existing fauna a chance to migrate into the new layer without rapidly burying and subsequently killing everything. I figured I would add a one inch layer at a weekly interval until I achieve the desired depth.

Any suggestions or critiques? Or is the DSB just a bad idea altogether?

 

[teamdulski]

Adam K,

With everything else your doing right now I wouldn't even bother doing a DSB.

Adam D

 

[teamdulski]

By the way, can you spare a ball of chaeto next week?

 

[BlackLagoon]

I'll bring some Cheato. Need anymore BCP's?

 

[Capt_Cully]

I investigated this a while back, but from what I recall, they have a finite lifespan. 6 monthsto a year. They need a lot of flow across the top of a very deep sand bed. I might be remembering this incorrectly. But the turn over in my refugium was not nearly fast enough, which was by design. I also want thrilled about buying bags of aragonite every 6 months. Plus I enjoy having my refugium bare bottom as they should be cleaned occasionally IMO.

If you have the room, you might want to investigate remote deep sand beds. Perhaps you have. But it can be done in a bucket somehow linked to your main system. Makes cleaning and sand disposal easier.

I think Gary M and tmz employ them, perhaps they can chime in and set me straight and provide some lucid insights.

 

[teamdulski]

I'm good on the BCP's, thanks Adam.

 

[EllieSuz]

I've never tried a DSB, but I've read a lot of threads that credit them with tank crashes. Unless you can do a remote one, I think you should leave well enough alone.

 

[tmz]

I would definitely not bury the old sand. You'll be burying organics which will fuel sulfate reducing bacteria which produce sufides and toxic hydrogen sufide gas as a by product. I'd either toss it or put some of it on top of new sand. But then I wouldn't put sand under any macroalgae anyway as it will get pretty messy from the algal exudate.

I run my chaetomorpha refugium bare bottom.

Remote deep sand beds don't really do much past the first inch or two of depth in terms of denitrification , imo and ime.
I have one 7 inces deep that I tried for nitrate reduction several years ago. It did not help. It's still in use with live rock piled on it to help advective flow into the sand for a litte more denitrification area and makes a good ambient lit semi -cryptic area for pods and sponges.

I've read Dr Shimeks works and they are helpful and impressive; just no longer a fan of deep sand beds as a first choice for dentirification. Certainly don't see how a remote one without the appropriate amount of live sand microfuana or another force to move nutrient rich water down deep at adequate volume can function effectively as a denitrifier beyond the first inch or so of depth. Denitrification does not need to be deep,anaerobic areas occur and support denitrification in shallow beds and rock surfaces and even in the bacterial mulm.

 

[BlackLagoon]

Thanks everybody. Sounds like there is a lot potential for things to go south with a DSB. I'm going to be adding a biopellet reactor to my system shortly. In the mean time I started dosing 30mL of vinegar 3 days ago to my 180g system. I plan to increase the vinegar by 10mL every three days until my nitrates start to drop or I get my biopellet reactor running.

TMZ - Congrats on tank of the month. I read in your system info that you had success with a sulfur reactor in eliminating nitrate. Would you recommend one to someone like me who has several large Tangs and struggles with keeping nitrates under control?

 

[cardiffgiant]

I agree with Tom and came to post pretty much the same thing.

I tried a sand bed in a fuge and ran into problems after a few months. The combination of the light, the chaeto restricting flow directly over the bed, and detritus settling onto the sand caused the bed to exhaust pretty quickly. I remember reading that turnover around 40-50x was better for a deep bed, and you usually see 20-25x in a refugium.

I also tried a remote deep sandbed that had not light and very high flow. IME, I couldn't fit a large enough bed in my system (at the time) to make a noticeable difference. I have more room with my basement sump and I haven't gone back to try it.

 

[BlackLagoon]

Well after reading what Tom and Randy have to say about biopellets I think I'll scrap the biopellet reactor idea as well and just stick with the vinegar.

 

[Capt_Cully]

You could consider adding vodka too.

Per a discussion I had with Tom/tmz:

Compliments of Tom/TMZ:


Vinegar which is 95% water is 8x more dilute than 80 proof vodka . When calculating a dose, 1 ml of vokda equals 8 mls of vinegar. You can use the vodka dosing start up guidelines for vinegar if you mulitply them by 8 .

Cost isn't much different. Bartons vodka is $14 for 1.75 liters ; vinegar about $3 per gallon. (3.9 liters).In terms of carbon content and equivalent dosing amounts 1.75 x8 =14 liters of vodka or roughly3.6 gallons of vodka. So @ $3 per gallon , it's approximately $11 worth of vinegar to equal $14 of vodka.

They can both go in a kalk reservoir together or separately. Bacteria will begin to consume either of them when they are diluted in regular water but not in the high ph kalk water.Off the shelf the low ph in vinegar is outside the tolerable range for the bacteria and the alcohol in the vodka stops them but when either of them is heavily diluted in plain water the change in environment favors the bacteria.

Vinegar in a kalk solution will also allow more calcium hdroxide to go into solution as much as 2.72 tsps per gallon with a dose of 48ml vinegar to 1 gallon of top off water vs 2 tsps per gallon. Adding more vinegar beyonde that has no additional effect on solubility This allows a higher dose of kalk than otherwise. Vodka does not increase the amount of kalk that can be held in solution.

Vinegar is fine,perhaps even a better source for carbon than vodka , but needs to be dosed slowly or in relatively small amounts preferably during photosynthesis. It brings in CO2 which drops ph quickly when dosed in bulk.
Vodka reduces ph from the bacterial activity as well and over time and equivalent amount of carbon from vinegar or vodka would even out but vodka is a step or two behind vinegar in degradation and CO2 formation so it takes it's time and the change in ph is not precipitous allowing time for equilration with the surrounding air along the way.. Since I prefer to dose it in bulk , a high proportion of vodka works for me

Just vodka may cause some cyano based on anecdotal observations .
Using some vinegar or all vinegar seems to more effectively limit cyano but that's all anecdotal at this point.

Tom

 

[tmz]

FWIW I personally bolus dose vodka and vinegar and have for 3 years. The bacteria in my system are adapted to this regimen.

Randy H Farely slow doses just vinegar during photosynthetic periods with success.

 

[tmz]

Well after reading what Tom and Randy have to say about biopellets I think I'll scrap the biopellet reactor idea as well and just stick with the vinegar.

These are the most recent posts from another thread on the Reef Chemistry forum which I believe you are referencing:

I choose to use GFO and ROX GAC in a canister and vinegar dosing I'm not a fan of pellets. One cannot really choose between GAC and GFO per se since they are use to accomplish different things, and the relative needs depend on what other nutrient export methods might be used in that tank.



__________________
Randy Holmes-Farley
Club 65535


All three do different things. FWIW, I also use gac, gfo and dose organic carbon. In my case it's vodka and vinegar;not a pellet fan either. As an example gac is is good at removing some organics ;organic carbon dosing adds them.



__________________
Tom



How come you're not fans of biopellets?


__________________
Mike



Several reasons:

They are polymers(carbohydrates) which first go to monomers( predominantly sugars) in the anaerobic digestion process as certain bacteria break them down and then moer bacteria work on the sugars Sugar dosing hurts my corals and others report issues including recission,cyano ,bacterial blooms etc when using them. There is one study linking high glucose to coral mortality.Ethanol comes further down in the chain of bacterial activity avoiding sugars ,acetic acid (vinegar ) is even further down The end product acetate is likely useful to corals.

It is clear that the bacteria and their by products don't confine themselves to the reactors as was originally claimed based on all the in tank effects reported.

Controlling the amount of organic carbon being dosed is difficult with the pellets since you have to rely on the volume of pellets, flow rates ,tumbles, variable volumes of pellets as they are consumed ,etc. All of which make it impossible to know how much of exactly what is going into the tank . When using directly dosed sources I know exactly what I'm dosing and in what amount. With vinegar and/or vodka,for example I know how much acetic acid and /or ethanol I'm adding .,So precision in setting and maintaining a dose is possible.

No reactors or pumps are required ,although direct carbon dosing can be automated via a dosing pump if desired.


__________________
Tom

 

[rossbryant1956]

Flow metric in an refugium

Flow metric in an refugium

I remember reading that turnover around 40-50x was better for a deep bed, and you usually see 20-25x in a refugium.

I am studying on refugiums and this is the first reference I have seen to a flow metric (gallons turnover per hour)...is this what this means? Do you guys agree or have different opinions. Thx in advance.