DSB

[Marine_Tank]

Hi,

Hope to get some more opinions abt DSB.

Currently, I am using grade 3 sand for my substrate which is about 3.5 inch deep. However, I am trying to increase the depth to 5 inch or more so that my DSB will be able to work efficiently as a natural nitrate removal. I heard that grade 0 or 1 sand is the best for DSB.

A few questions about this DSB:-

1. Can I use grade 3 sand and top up with grade 0 or 1 which is finer and better ?

2. Is there a way to change all the sand to grade 0 or 1 from my current grade 3 sand without having to move anything like fish etc ?

3. What must I do to carry out this topping up exercise and any precautions that I must take ?

My FOWLR tank is currently abt 1 year old using coral chips as filtration and normal overflow with wool.

Thanks for yr advice.

[Achilles Tang]

1. Theoratically, fine sand will trickle thru bigger particles and settle at the bottom. That takes some time.

2. If your tank is established, upsetting your water quality by removing your old sand can be disastrous. Esp. with large grain sandbeds which will undoubtedly trap a lot more detritus than fine sandbeds.

If you really want to do this operation, buy the biggest toyogo tub you can get, transfer all the water and LR out... put your livestock in, put the skimmer in there (for oxygenation and clearing of dissolved wastes) for at least a week while you do up your sandbed.

Remove all the old sandbed, give your tank a good wash... add in the new sandbed. This will mean that your tank's sandbed will have to start all over again as a biological filter.

You now have to count on your LR and frequent water changes to maintain good water quality as the sandbed will need a lot of time to mature and cope.

Best if you give away some fishes to reduce bioload.

I did this change to a new sandbed when I migrated my old tank to my current tank. It's a lot of work!

[Air]

does ur overflow flow to a sump?

[Marine_Tank]

Thanks AT.

Aside to Air,

My tank water will flow into a compartment (right side) which contains coral chips. It is linked directly to the pump chamber (left side). To be exact, my custom-made system filtration is working in a circular flow manner, so I don't have a sump like the wet/dry filter system. Really wish I can have a complete change to that....$$hahahahaa$$

Anyway, it is safe to top up with grade 0 or 1 sand and get rid of the grade 3 sand when the fine sand (grade o) has filtered down to the bottom. I think this process takes quite a long time. Bit is this feasible ?

Another question is whether it is safe to do that when your DSB is more than 6 inches deep ? Will there be any complications for the livestocks etc. My tank height is about 2.1 feet. Let me know if you need more data abt my tank specs.

Once again, thanks for yr great advice