DSB in a bucket for nitrate control

[ziyaadb]

Hi all

Can someone please advise of what would be the best flow for a RSDB? i have a 100G in the process of setting up, i have already bought a black bin/bucket thats about 18G and i am gona build a small platform so that its higher then my sump. how much of flow would i need for the rsdb to function well?

Thank you

 

[Tony25]

I have a empty 55 gallon sump.
Is there any reason that a bucket/Pail full of aragonite sand in my slow flowing sump wouldent be ok or the same?

 

[snorvich]

Generally, about 300 gph seems to work well. The most important issue is that no light reaches this area so things don't grow there.

 

[wayne in norway]

I haven't contributed to this at all, but would recommend anyone interested in how this might work to look at the paper by Huettel et al from 1996, or at this paper Huettel et al 2003 http://www.aslo.org/lo/toc/vol_48/i...D7EF85B9B9160A=0&bcsi_scan_filename=1674.pdf. The same author has produced a whole string of experimentally demonstrated work on transport thro' marine sandbeds well worth reading.

If you really want your sand bed to work, you want a fast flow rate first, then fluctuations like a wavemaker on top. Messing around with temperature is something I've considered as a minor effect w.r.t. changing density on top of the sandbed affecting diffusion and advection, but is not where I would concentrate my energy. FWIW I routed my skimmer outflow over my dsb and get about 8 cm/sec water flow - gph is meaningless to me.

 

[Tony25]

Ok im going to give this a try. I have a 30lb bag of sugar size aragonite and about 10 lbs of seafloor grade on top in a sterlite container in my 55 gallon sump.
My nitrates are at 20 ppm.
Im not going to do any water changes and see what the nitrates do. Im pretty confident they will drop to 0 eventualy with no water changes.
Here are some pics

 

[Tony25]

 

[Tony25]

My tank is 90 gallon and the sump is 55

 

[wayne in norway]

Straight off I think you'll be lacking flow over the top of the sand bed. That's based on theory and my own practical experience. I don't think that's going to work so well.

 

[Tony25]

Well the return pump is 1900 gph i know i get alot of head loss but im pretty sure its at least 300 gph.
I could also point the flow from my canister filter over the sand.

<a href=showthread.php?s=&postid=13467809#post13467809 target=_blank>Originally posted</a> by wayne in norway
Straight off I think you'll be lacking flow over the top of the sand bed. That's based on theory and my own practical experience. I don't think that's going to work so well.

 

[Tony25]

.

 

[wayne in norway]

That 300 gph from the return pump will go straight over the baffles, and even if you raised the tub of sand into that it will still be messed up by the top of the tub deflecting the flow. You need brisk flow right over the surface of the sand. 5 cm/sec + at least. it's the interaction of the moving waterwith the sand surface that gives you movement inside the sand bed. All you'll be getting is diffusion, a relatively trivial movement.

 

[Tony25]

Do you think it would help if i pointed that canister filter flow over the sand bed? Or maybee a 325 gph mag pump?

 

[wayne in norway]

I'm getting 1000 lph or so coming out of my skimmer and I route that via 40 mm tubing over my sand bed. Using the cannister will do the same for you. My fear with the 325 gph pump is that you will jsut throw out all the sand, but it's the sort of thing I've done in the past.

 

[snorvich]

I have approximately 5 inches of water flowing over about 15 inches of sand with a flow rate of 325 gallons per hour. No light can get to the sand or inside of the container. Works well. However, these are on REEF tanks which normally have low nitrate as opposed to FO which are higher in nitrate.

 

[barks]

hi,
this is an interesting read.
i found it really help full.Click Here and go to guest articles and sand beds parts 1 & 2.

regards
barks

 

[jasonak]

Which type of sand are you supose to use? In the begining of this thread its says oothic but other threads so do not use oothic.My local home depot only has this black looking sand?

 

[t kish]

Wow 66pages of some great information and the same questions being asked over and over again.

This thread is a few years old now and it would be interesting to hear from some of the earlier test pilots to see what their results have been.

TKish

 

[ladyshark]

I saw at least one person ask this and didn't see an answer (could have missed it tho) and I have the same question. Please forgive me if this was already addressed.

I don't have a sump--just a 75 gal with HOB skimmer and canister filter. If I added a 5 gal RDSB, closed loop, I am thinking it would be best to have a pump in the DT on the return tubing, pulling water from the tank, through the DSB back into the tank. Does this make any sense at all? IF not what would be a better setup?

THANKS

 

[ebayes11]

Unless the bucket seals, it isn't a closed loop and you'd have the same drainage issue when the power went off. The best way to do it seems to have the RDSB drain into the sump, although it could conceivable be above it too. Just realize that unless the bucket seals (and may need to be devoid of air) you wont have a closed loop.

 

[Jhardain]

If you have a RDSB of 20" is the sand deeper then the initial 8" or so wasted sand? Meaning it has been posted to have DSB of 6-8" or so, so if it is deeper is it just wasting your money on the sand?