Deep Sand Bed question

[Nicmar]

I am wanting to use a DSB in my new 800L tank.
I want the sand bed to be 150mm in depth.

I am thinking of using two types of sand, sugar fine and 1-2 mm.
Should I use the sugar fine at the bottom, about 50mm then 100mm of the bigger stuff?

Also once fill of water can I move all my SPS and fish straight away from my existing tank?

 

[dave.m]

From what I've read on grain size, the smaller grain is more efficacious. As for when to add your fish and inverts, you need to allow a few weeks for the DSB to become populated with bacteria. That means feeding an ammonia source, just as you would to activate your live rock and substrate (if any). Only through regular measuring will you be able to tell when your DSB has started to kick in as an active part of your filtration system for nitrates.

Something you should also be aware of is that DSBs die within a few hours of a power loss/lack of flow. Once they go moribund you need to discard the sand completely and start again with fresh sand. A UPS may be helpful for the pump that feeds the DSB, especially if your area is prone to power outages.

Dave.M

 

[Nicmar]

From what I've read on grain size, the smaller grain is more efficacious. As for when to add your fish and inverts, you need to allow a few weeks for the DSB to become populated with bacteria. That means feeding an ammonia source, just as you would to activate your live rock and substrate (if any). Only through regular measuring will you be able to tell when your DSB has started to kick in as an active part of your filtration system for nitrates.

Something you should also be aware of is that DSBs die within a few hours of a power loss/lack of flow. Once they go moribund you need to discard the sand completely and start again with fresh sand. A UPS may be helpful for the pump that feeds the DSB, especially if your area is prone to power outages.

Dave.M

Thanks Dave. Good advice.

Yeah we have a few outages and it is only getting worse with the growing population.

I currently have a bare bottom tank and love that I don't need to do any cleaning. I don't want to be busy cleaning the sand every few days which is what I have done in the past before I pulled it all out. I think the grain size was too small then as it blew around the tank daily.

I have x1 battery back up on one of my mp40s and considering a UPS for the return pump and heaters.

I am also on a time frame to get this up and running since I am moving my existing tank before xmas then going away so that needs to be taken into account regarding a cycle.

Am I best to ditch the sugar fine and go with a 50mm (2 inch) sand bed 1-2mm grain size and clean it every 2 weeks?

 

[dave.m]

The article I linked shows that the 2.0 mm sand grain size is better for the DSB.

I am referring to an isolated DSB as opposed to a tank substrate. Are we talking the same thing? You would not touch/clean an isolated DSB. You would ensure constant and adequate water flow over the top of the DSB - ~190 lph/50 gph. The DSB works by chemical action on the nitrates in the water by osmotic pressure. Disturbing the sand would negatively impact the bacteria and cause them to have to regenerate to resume optimum function after each disturbance.

Dave.m

 

[Nicmar]

No, I am talking about a DSB in the display tank not in the sump.
I just want it for looks. A clean white sand bed with little maintenance.

Should I use a DSB or stick with shallow or even glue down a thin layer of sand?

I don't have much experience with sand since I removed it after a few months of setting up my tank and have had bare bottom for the last 5 years.

 

[HumphreyBear]

I wouldn't use an in-tank DSB if you just want ornamental sand. In your shoes I would go shallow and get a CUC that will go over the sand for you

I've not tried the glued-down approach but it seems potentially risky (ugliness and various stubborn growths) unless well executed. Robert Lopes on here has a nice one that you could emulate.

All tanks need to cycle, if you are taking your existing filters and rock over then you can accelerate it, but it still goes through a cycle and settling period.

Cheers,
The Bear

 

[dave.m]

+1

Okay, we are really talking at cross purposes, here. I would not call a couple inches substrate on the bottom of the display tank a deep sand bed. As HB has noted, get yourself a good clean-up crew, including conchs and nassarius snails to keep your sand clean. A good crew should negate the need for you to stir/vacuum the sand. Other members would include the small blue-legged hermit crabs and whatever bristle worms come out of your live rock. Sand-stirring gobies are very entertaining but will re-arrange your sand bed for you constantly. Sea cucumbers are very effective but deadly when they die.

Be careful of overfeeding, which is the prime cause for concern with sand bottoms.

Dave.M