Help phasing out DSB

[FortyFour]

I've been running a DSB in by refugium for almost 5 years now. My experience has been good, at least I think it has. However as it gets older, I feel like more can go wrong with it than good. I haven't maintained it so far other than removing detritus from the surface, which over time has turned my 6in DSB into more like 5in.

I've enjoyed the debate on the topic going on in this forum. Ultimately, I'm leaning towards phasing it out and leaving more room for liverock and macro algae.

1. If you have an opinion on this logic, please share

2. My plan would be to disconnect my refugium (15G), remove the sand, and do this as part of a larger water change. In your opinion, would this shock my tank (80G)?

3. Pods. I'd lose some but they'd replenish in time.

4. Is there anything else I should be thinking about? Thank you!

 

[Green Chromis]

:fish1: Hi Jbuajr, I removed the DSB from my refugium last July, about 1200lbs of sand collect from the reefs off the Florida Keys, never had a problem and I removed the sand over a period of 3 weeks. I isolated the refug from the rest of the system as the sand was very dirty, but kept the water circulating in the refug so it would not become stagnant and kill all the life in the refug. All the sand was returned to the ocean. If I ever use a DSB in a refug again I will use filter socks to remove a lot of the waste that would collect in the sand instead of the socks. :fish1:

 

[FortyFour]

Thanks for sharing. So just to confirm, you were more concerned about the possible ill effects of stirring up your DSB than you were about cutting off the refugium to your DT for 3 weeks?

Before I read your post, I was contiplating removing the DSB 25-33% at a time, but reconnecting the refugium to the DT after replacing all the water that was stirred up. Would you advise against?

 

[FortyFour]

Another poster in the mega DSB thread indicated that they as well removed in increments to minimize any swings in chemistry.

I've been under the impression that a DSB will have layers of ammonia which is why I'm preceding with caution, and trying to figure out if ill be:

A) removing in increments while detached from the DT over a period of time B) removing in increments, but reattaching to DT after replacing the stirred up water each time, or C) removing in one shot, while detached, and replacing with the fuges own water (pre removing sand) after giving time to settle. Possibly treating with PRIME as well.

 

[Apotack]

I would remove small amounts over several months. Why rush, small changes widely spaced are always the way to go

 

[karimwassef]

As a test, do you have the option to bypass the DSB section? Circumvent it with pumps and plumbing?

If it's possible, you an just divert 25% of the flow, then 50%, ... Until very little flows over it. Then you can just remove it all and start clean.

 

[karimwassef]

For what it's worth, I think DSB is often maligned without a real basis.

IME, If managed properly, it's golden.

 

[Green Chromis]

:fish1: I love my DSB in my refug, I will be setting up another one this coming summer, when I can go out and collect the sand. The reason I use a fuge in a DSB is, I am able to disconnect the fuge from my system without any harmful effects to the main system. I'm running my fuge bare bottom right now, with a few pieces of live rock and macro algae for PO4 export. If you cannot bypass your fuge with a DSB you need to remove a small portion of the sand on a weekly or monthly basis, testing your water in-between the removal of the sand. :fish1:

 

[FortyFour]

I would remove small amounts over several months. Why rush, small changes widely spaced are always the way to go

This is what I've been wrestling with, because I agree with what you're saying.

But I'm worried that by removing layers slowly over time, I will eventually get to toxic layers deep in the sandbed and release it into my tank. And since I have the ability disconnect it from my display completely, there might be a safer way.

Thanks for the feedback everyone.

 

[FortyFour]

As a test, do you have the option to bypass the DSB section? Circumvent it with pumps and plumbing?

If it's possible, you an just divert 25% of the flow, then 50%, ... Until very little flows over it. Then you can just remove it all and start clean.

Yea, I have that option and I'm weighing this approach.

For what it's worth, I think DSB is often maligned without a real basis.

IME, If managed properly, it's golden.

I've always thought so too, but I don't think I've managed it properly and feel like it's something waiting to go wrong for me.

 

[reefgeezer]

So If I read correctly you have a DSB in a 15 gallon fuge. Maybe 7 gallons of sand if the DSB is less than 6" deep? How big is your system (DT + Sump Volume)? Are your nitrates currently low? If you have more than 50 gallons and have almost no nitrates, I'd just take out the sand in one shot. I say that because, IMO, a small DSB (less than 1/8th the total system volume) does little nitrate control in a big system. I also believe that messing with an old, not so well maintained DSB is not a good idea.

 

[Green Chromis]

This is what I've been wrestling with, because I agree with what you're saying.

But I'm worried that by removing layers slowly over time, I will eventually get to toxic layers deep in the sandbed and release it into my tank. And since I have the ability disconnect it from my display completely, there might be a safer way.

Thanks for the feedback everyone.

:fish1: Hi jbuajr, if you can remove it from the system, do so and clean the tank and replace the sand. How much rock and sand do you have in you DT? Will it be enough to keep up with the Bio Load in your DT? :fish1:

 

[Windy2]

Just so you know, there isn't anything very toxic in a sand bed. I have moved mine from a 120 to a 90 with a scoop. One scoop at a time, then put my live stock back in the fairly dirty water. Nothing died including my invertebrates.
I am currently removing my DSB because the old acrylic tank it is in is cracking. I am putting the top 1-2 inches into a separate 20 gal high to try to save some of the infauna. I am taking a few scoops every 3-4 days. I will then disconnect from the system and
siphon all of the rest of the sand out at one time.

 

[Subsea]

I see no reason to drag it out. Do it all at one time.

I have operated DSB for >30 years. I stir the surface of mine daily to create a detritus snow storm. At times, I have stirred too deep and could briefly smell H2S. From previous hydrogen sulphide training in offshore drilling, I can assure you that H2S can be smelled at 10 ppb. Once it gets to 100 ppm, you will lose your sense of smell and shortly thereafter, you will die. From smelling it to dieing from it is a factor of 10,000. The point that I wish to make is that many elements that are considered poisonous are not only not lethal. In proper concentrations, they are required for many enzyme reactions in our corals and fish. I was stunned to find out that macro algae requires cooper and zinc.

 

[BeanAnimal]

Just so you know, there isn't anything very toxic in a sand bed.

Sure there is... the sandbed has sequestered all kinds of organics and compounds. A true DSB will have an anaerobic layer and depending on size, depth and health, can have very poisonous amounts of hydrogen sulphide.

In general, one should be careful when disturbing large areas of a DSB at a time.

 

[BeanAnimal]

I see no reason to drag it out. Do it all at one time.

I have operated DSB for >30 years. I stir the surface of mine daily to create a detritus snow storm. At times, I have stirred too deep and could briefly smell H2S. From previous hydrogen sulphide training in offshore drilling, I can assure you that H2S can be smelled at 10 ppb. Once it gets to 100 ppm, you will lose your sense of smell and shortly thereafter, you will die. From smelling it to dieing from it is a factor of 10,000. The point that I wish to make is that many elements that are considered poisonous are not only not lethal. In proper concentrations, they are required for many enzyme reactions in our corals and fish. I was stunned to find out that macro algae requires cooper and zinc.

The concern with releasing the HS is not so much YOUR health, but that of the livestock. Their tiny blood/oxygen volume takes far less to overload than yours

Releasing a fair amount of HS and anaerobic material can easily kill fish and inverts.

 

[Subsea]

The concern with releasing the HS is not so much YOUR health, but that of the livestock. Their tiny blood/oxygen volume takes far less to overload than yours

Releasing a fair amount of HS and anaerobic material can easily kill fish and inverts.

Yes, I hear the logic.
In my experience, I have not found it to be a problem. Perhapes the creatures are hardier than we think.

Also, in this thread, I did not say to mix up the contents of DSB with the water column. I said to remove it all at one time, thereby minimizing what you consider dangerous.

 

[outy]

removed mine all at once, no problems . over a foot deep


glad I did, never worked great

 

[outy]

Sure there is... the sandbed has sequestered all kinds of organics and compounds. A true DSB will have an anaerobic layer and depending on size, depth and health, can have very poisonous amounts of hydrogen sulphide.

In general, one should be careful when disturbing large areas of a DSB at a time.

So true.

Every time I have removed a DSB the smell is terrible, nasty.

 

[FortyFour]

:fish1: Hi jbuajr, if you can remove it from the system, do so and clean the tank and replace the sand. How much rock and sand do you have in you DT? Will it be enough to keep up with the Bio Load in your DT? :fish1:

Yes, there's enough live rock in the display and sump to keep up.