Deep Sand Bed In Sump

[pipatic]

when i set a sump on my next tank i was think about leaving a section for sand bed say in the middle of the sump ,
what would be the benifits of this

[Glenn@home]

Im not sure that the answer is black and white.

I have a DSB in my sump, the tank is 6x2x2 the sump 3x1x1.5.

Im not sure what benefits are realised with a sand bed this size in relation to the tank, bearing in mind that size maybe isnt the best arbiter here but the imposed bio load is but is more difficult to quantify.

I dont think it can do any real harm to have a small sand bed in the sump, whether its essential or really benificial is another matter.

If you are going with live rock and good flow in your tank then its likley that they will provide all the nutrient removal you need.

JMHO

GLenn

[InTheDeep]

it provides an area to grow macroalgae and promote organisms tat won't grow in your main setup. It also denitrifying du to the low oxygen contents at the lower levels - I think this is right?

[Glenn@home]

ITD

You make some points which whilst true, also have drawbacks to them in the sense that when the water from the sump needs to be pumped to the main tank, the benifits of having additional pod life are largely lost due to the potential for pods to be damaged when they pass through the pump. I presume that most people promoting the growth of pods outside the tank are essentially doing it as a form of free food for the mian tank inhabitants.

Re the denitrifaction process there is an argument which suggests that trying to deal with waste with a remote DSB is in fact less efficent than the same process carried out in tank by lr or an in tank dsb. I am not certain how relevant or real the potential problem is in this respect.

One thing about macroaglea and dsbs is that if you are not careful the algea will put donw roots whihc means when you harvest it, you may disturb the dsb. I have macro algea in my sump where the dsb is and wont be doing it again.

JMHO

Glenn

[danny]

A sand bed or any gravel bed would provide extra suface area for bacteria and an environment for organisms to break down waste. It could also be lit and used for growing macroalgae.
With an external filter used in the conventinal manner traps large waste particles where it is broken down almost entirely by bacteria (rotting effectively). In a sand bed that waste is eaten and reused by a chain of detritovores and small organisms so the finished waste products are much smaller and impact less on the system.

[Glenn@home]

Danny

Glad you chipped in, do you have any thoughts on the relative size of DSB v tank size?

I have wondered recently about some of the small sand beds you see in small sumps under largeish tanks, mine could be a good example.

As you will probably recall i have noticed some good improvements to tank parameters since removing some rock a while back and changing the way the pumps work to improve flow.

Arguably if my dsb was working well then its unlikley changing the rockwork in the tank and arguably flow, would make no difference to my parameters.

Glenn

[danny]

Glenn,
Perhaps increasing the flow in your tank has resulted in more waste reaching your sump and so feeding your DSB leading to improved parameters. Probably not the case, but just a thought. Is your DSB aragonite or silica sand, I can`t remember?

I must admit I don`t like the idea of the slightly sharp and regular shaped play sand as I feel sure that it would not be an ideal environment for such a wide range of creatures.
Ideally I would guess the bigger the bed the better, but I am increasingly beginning to wonder if coarser gravels or perhaps a mix is the way to go. It makes sense to me that the more exchange that is able to take place in the upper layers of a sand bed the more effective it will be. This would allow a smaller area of substrate to filter a larger tank possibly.
Jaubert style systems (basically a coarse gravel DSB) are not popular here, but they are probably the cheapest way to set up a tank. Due to their efficiency you can use them as a sole filtration (still with a skimmer though) without the need for live rock apparently, infact it is recommended that liverock is kept to a minimum. This is partly because less is needed and partly to prevent covering the substrate.
Danny

[jamie reefer]

Hi Glenn

When you mention about marcoalgae in with the dsb sending down roots, have you removed all the marcoalgae from dsb compartment as I have the same problem.

cheers Jamie

[SPS Hoover]

Arguably if my dsb was working well then its unlikley changing the rockwork in the tank and arguably flow, would make no difference to my parameters.


But it would if now the deritus can get to dsb which it couldn't before your change around ie trapped under certain rocks.

I would have to agree no algea in with dsb is ideal, but not everyone has a sump where you can have seperate areas.

Also i think a dsb pod life is better with no light.

The sump to tank size question now that would be total guess, i believe we are no where near answering that

JMO

[pipatic]

bigger the better from the sound of things,depending on stocking levels etc ?

[Glenn@home]

To answer some of the queries re my set up.

The rockwork i removed undoubtedly harboured some crud, i would be truly suprised if it made a difference since the other 40 odd kgs will also be harbouring crud too.

I know you guys havent seen it, apart from Danny, but i have in the past had problems with crap on the rocks, it isnt entirely cured but it is a lot better. Being perfectly frank i would have to take everything out of the tank to remove all the last vestiges and since things are currently going my way i dont think its worth it.

Re my macro algea, no i havent removed it since i live in hope that it would grow well and help reduce nitrates and phosphates. Since putting a growlux tube over it things do seem to have perked up a bit in the sump and unless i have to i wont remove it.

When i move my sump to the garage one of the things im going to build is a fuge as opposed to a sump.

Should say i am planning on a sump with sand bed, flow from tank, kalk addition, chiller supply/return, heating, rowa (when i get round to building a reactor) auto top up all in a 6x2x2, a sump for macroalgea in a 25gallon coldwater cistern, and a 3x1x1.5 fuge for bits and bobs.

I havent fixed the plans yet but like most of us when we're planning we have the concepts and ideas at least.

SO im hoping to get closer to ideal conditions and make life a whole load easier, just wish i knew then what i know now and i wouldnt have made half the decisiosn i did.

Glenn