Remote Deep Sand Bed

[FocusFin]

I originally discussed this in a different thread http://ovas.ca/index.php?topic=27358.0 but thought it might be better suited for the DIY section.

First off, thanks to Funkmotor and Redbelly. Your suggestions were bang on.

In order to reduce my nitrates I wanted to set up a remote deep sand bed (RDSB) but without the benefits of drilling the tank or using an overflow. This design could not be allowed to flood under any circumstances.

For those not familiar, the purpose of an RDSB is to reduce nitrates by cultivating anaerobic bacteria in the bottom layers of sand and is especially useful for tanks like mine where the sand bed is not deep enough.

For the design I used a 5 gallon salt bucket (Instant Ocean), 3/4 inch cpvc and a Maxijet 1200. My tank is 56 gallon.

The idea is to fill a bucket to within 3 to 4 inches of the top with sand (preferably aragonite) and flow your tank water over top. The specifics are covered in this rather long thread on Reef Central http://reefcentral.com/forums/showthread.php?s=&threadid=595109&perpage=25&pagenumber=1 . The difference with this design is that the bucket would be completely sealed so that it could not overflow and flood.

I first drilled the bucket about two inches from the top and put in two Push and Turn bulkheads. I would suggest regular bulkheads instead as the Push & Turn have to be torqued so it makes it difficult to know how tight to make them.

The powerhead was mounted into the bulkhead instead of the lid to reduce vibration and therefore noise. I inserted a small piece of 1/2 inch clear plastic hose into the bulkhead as a sleeve and then inserted the flow tube of the powerhead into the sleeve. It made a very snug fit. I ran the powercord through the intake pipe so that I wouldn't have to drill yet another hole and increase the chances of a leak. A word of warning, thread the cord before assembling the cpvc because it will not go through once the pieces are glued together.



Assembled the cpvc and did a dry run.



The most difficult and most important step was sealing the bucket so that it would not leak. I siliconed over top of the seal in the lid and also filled all of the threads around the rim of the bucket. Once everything had dried I turned the bucket over and filled any remaining gaps between the bucket and the lid.

The beauty of this setup is that the bucket never contains more than 2 gallons of water so in the event that the intake pipe gets obstructed the powerhead will pump the contents of the bucket into the tank and 2 gallons of water will only raise the water level in the tank by 1 inch (based on my 56 gallon - 30inch long X 18 inch wide).

Conversely, if the powerhead fails the bucket will simply fill to capacity and the flow will stop. As soon as the pump restarts it automatically creates suction in the bucket and the siphon begins. During feeding or waterchanges the powerhead can be shut off and once resumed there is no need to prime the intake to get the siphon going. In the event that the bucket leaks I've placed it into another container which will hold an additional 4 gallons of water. The intake pipe in the tank is set to 1 inch below the level of the water so that only a maximum of two additional gallons of water would ever siphon in a worse case scenario.




I started the initial siphon by sticking the flow tube of a maxijet up into the intake pipe in the tank which filled the bucket with water. I then turned on the powerhead and away she went.

I have been running it now for 3-4 days and have had no leaks from the bucket/lid yet. I did notice that the powerhead was pumping out the bucket slightly faster than it was filling giving an occasional slurping sound. This was probably due to the powercord causing a slight obstruction down the intake. I countered that by placing a 3/4 to 1/2 inch reducer on the end of the outflow pipe and the flow is now perfect.

Provided that the bucket holds its seal this setup should work for any tank that has two gallons of spare room in case it  overflows.

I won't know for 4-6 weeks whether this had any benefit but my nitrates were 20ppm after an 8 gallon waterchange so we'll see what happens. In the meantime, there is an added bonus in that the addition of the aragonite will help with buffering.


Mike

[Funkmotor]

Oh, nice job.  I've been occupied with other projects and it's nice to see one come together.

What can I say...I'm an ideas man.   

Very interested to see what it does to your nitrates in a couple of weeks.

[gvv]

Interesting... Would like to know how it will affect nitrates.

Just a question - can a fish get into the intake? I know my clowns love to swim near the surface and several times I had to caught them from sump.

Regards

[FocusFin]

Interesting... Would like to know how it will affect nitrates.

Just a question - can a fish get into the intake? I know my clowns love to swim near the surface and several times I had to caught them from sump.

Regards

I bought a cpvc end cap and drilled about 20 tiny holes in it which works well as a strainer, however it also causes a difference in the flow so I am going to either put a Y on the intake with two caps or some type of a small basket over the intake that will keep out the fish, snails etc.. but won't obstruct the flow of water.

[Darth]

So how goes the project Mike? I am really interested in this since we have the same tank. It would be something I may look into if it works well for you

[FocusFin]

So how goes the project Mike? I am really interested in this since we have the same tank. It would be something I may look into if it works well for you

I know what you're after and I'm not fragging my torch yet

Coincidentally, I did a water change about an hour ago and the nitrates were still around 20ppm but I'm not expecting a change for at least another 2-3 weeks. I'm glad you asked though because I was thinking of posting an update.

The construction is holding up fairly well but I'm still getting a bit of leaking from the lid on the bucket when I shut the powerhead off and the pressure increases. I siliconed the h*ll out of it before putting it on but it's still not foolproof.

I would like to find a bucket that has a lid you can clamp down similar to a cannister filter that you have to snap closed.

I'll post the results in a couple of weeks.

Mike

[RossW]

I would like to find a bucket that has a lid you can clamp down similar to a cannister filter that you have to snap closed.

A Fluval FX5 would do the trick, it is large enough, has awesome clamps/screws... just don't know where you would find one and if you could it would probably not be an economical option.

[FocusFin]

The fluval holds 2 gallons. The bucket 5 gallons.

I would have to check the RDSB link to see if it's big enough but it's a great idea if you could find one that's not working, otherwise the cost would be prohibitive. You would not want or need any of the inside parts, just the cannister.

If it's not large enough for a 56 gallon it might be perfect for a nano or slightly larger tank.

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[sas]

Might I suggest checking out a wine making store? I have a bucket, pretty sure it's at least 5 gallons if not bigger which we used to use for wine making. The lid snaps on very tightly and also has a white rubber seal that fits in the lid. A few well placed clamps may just do the trick. The only drawback is, it has the small hole in the centre of the lid.
I've also noticed that the brew your own stores have some awesome large drums, and know for a fact they will part with them occasionally for the right price. Hope that's of some use.

[FocusFin]

Might I suggest checking out a wine making store? I have a bucket, pretty sure it's at least 5 gallons if not bigger which we used to use for wine making. The lid snaps on very tightly and also has a white rubber seal that fits in the lid. A few well placed clamps may just do the trick. The only drawback is, it has the small hole in the centre of the lid.
I've also noticed that the brew your own stores have some awesome large drums, and know for a fact they will part with them occasionally for the right price. Hope that's of some use.

That's a good idea. I'm assuming the little hole in the lid is for the fermentation? The hole could be made bigger to fit a bulkhead.

I live near "The Station" on Bank street which is a brew your wine place so I will check it out.

Thanks,

Mike

[FocusFin]

I found this on Reef Central. No lid.

I might switch to something like this when I've determined if this whole thing reduces my nitrates.

I don't want to disrupt the process now which would require removing all of the sand and funneling into a new container.

We'll see in a few weeks if this is worth pursuing.






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[RossW]

Awesome idea and should be readily available, I would hope.

I will also wait for your results before I jump in.

Ross

[RossW]

Walmart has these for like $9, I think 7 g.



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[FocusFin]

I didn't think this through very well. How do I get the powerhead into the container?

The opening would have to be a minimum of 3 inches and the bulkhead would also have to be fitted partly from the inside.

If the powerhead can fit through the opening then this is a great option. I'm going to check it out today.

Thanks Ross

[Zzippper]

Did you use aragonite sand? If so - where did you get it and how much did you pay for it?

Thanks in advance.

Z

[FocusFin]

Did you use aragonite sand? If so - where did you get it and how much did you pay for it?

Thanks in advance.

Z

I used aragonite over silica sand because there is some opinion that silica can cause a diatom bloom. Also, aragonite is supposed to help with buffering.

A member was dismantling his tank had 50lbs of live rock for sale for $100.00 and offered to throw in the aragonite for free. I figured I could cure the rock and then sell it later but the aragonite was just the amount I needed.

If you're in a hurry try Petsmart ($26.99 for 40lbs) if not keep asking on the site. Somebody will be dismantling a tank soon.

[Zzippper]

Has your RDSB produced any results yet?

FYI - I also set one up a few days ago. Teed off my sump return line to the RDSB bucket. Gravity fed return from the RDSB bucket back to the sump.

[FocusFin]

Has your RDSB produced any results yet?

FYI - I also set one up a few days ago. Teed off my sump return line to the RDSB bucket. Gravity fed return from the RDSB bucket back to the sump.

I had a major setback over the weekend. I was adding some trim to my canopy and had to remove the bucket in order to cut down the drain and return pipes so that they would fit snug against the rim of the tank. I jostled the bucket and dislodged the powerhead inside.

I had to unseal the bucket to reattach it and decided I might as well take the opportunity to find a better container to use.

I bought another bucket of salt (Coralife this time) and instead of removing the lid and disrupting the factory seal, I've cut a 3 inch diam. hole to remove the salt, add the aragonite and install the bulkheads and powerhead. I'll then silicone a larger piece of plastic over the hole.

I figure that it will be easier to manage a leak from a small area on top of the lid rather than multiple leaks from the rim/lid around the entire bucket. Also, I can remove the piece of plastic if I need access inside the bucket and then simply re-silicone it.

I don't know how far this has set me back but I have to assume the worst case scenario is that I'm starting over.

You will have none of these problems so you might be seeing results before I do.

[Zzippper]

Wow - bummer.

To be honest, as I've followed this thread since you started it, I kinda had a gut feeling that the powerhead 'mount' was an accident waiting to happen. Weakest link in the chain so to speak. I didn't want to say anything and jinx things - plus you had already siliconed things shut.

Can I make a suggestion? In addition to siliconing the plastic piece over the hold, I would strap it in place with big stainless steel hose clamps (the worm gear type). I am not sure if they make hose clamps that large - but ... you get the idea.

Finding a more secure 'mount' for the powerhead would also be a good idea. I am going to think about this one and will let you know if I come up with anything.

Z

[FocusFin]

I didn't want to say anything and jinx things - plus you had already siliconed things shut.

Z

No, but you thought it didn't you. I knew that this was more than just an "accident"

Finding a more secure 'mount' for the powerhead would also be a good idea. I am going to think about this one and will
let you know if I come up with anything.

Z

I'm going to work on that. Thanks for the input.

Mike