My soft coral reef has been running in excess of 5½ years. 3½ years ago I decided to add a DSB (deep sand bed).
I know the above periods are correct as I keep a notebook.
The aquarium was running without any problem, the decision to incorporate a DSB was driven by interest. I wanted to see if I could develop a bed that was full of life as described in various articles.
I haven’t the space for a full size DSB, that is one of the size that follows the guideline. It had to go in-tank as well, and fortunately there is a divider in the tank separating the display area from the pump area. The DSB went in the pump area and is very approximately about one twelfth of the base area of the whole aquarium, or perhaps even less. Therefore any effect on the seawater would be minimal (nitrate reduction for example) but, as said, I wanted one out of interest.
It was constructed with fine sand to a depth of just over 4″ (circa 10 cm). I remember that though I had cleaned the sand as best I could, the display looked like it was wreathed in a thick fog for quite a time. After a few hours it cleared without any ill effects.
The DSB sat there looking very clean and tidy for quite a time. Then I obtained a small amount of sand from Peter’s DSB and laid it on the top. This sand was fairly coarse and sits in a very thin layer on top of the fine sand.
The hope for life appeared, and also no doubt some of it took up residence after moving from the display area. The display area when viewed at night with a torch is quite rich with little shrimps, snails and the like.
After about 6 months the surface of the DSB was a small sea of short waving tentacles, which belonged to small life forms trying to find food in their immediate area. In addition there were a lot of tiny shrimps running about – this was at night when viewed with a torch. In addition there were a few creatures, very small about ¼” (circa 6mm), which swam about, their eyeballs being picked out by the torchlight. The looked a little like brine shrimp but they were not.
This went on, with me feeding the DSB once weekly with small frozen fish pieces. When the fish went in the worms popped their heads up quite quickly, recognising that lunch had arrived.
The worms obviously lived in the sand, but I started wondering were the little shrimps etc lived. The DSB is flat – maybe they were in the sand too? Seemed a bit unlikely to me, but I never managed to track anything back to its lair.
I wondered if I could provide a better habitat for the tiny life. Therefore, 6 weeks ago, I placed some rock rubble at one end of the DSB. The rubble was that from the original rock that I had used to construct the reef – inert and very porous.
The rock is very light which is good, it won’t compact the DSB. The rubble pieces are around ½” to ¾” and form a light layer about 6″ wide and 8″ long. The major area of the DSB remains flat sand.
There has been a clear increase in the DSB population. The tiny shrimps have increased the most, and to a lesser extent so have the ’swimming eyeballs.’ Feeding the DSB has not been increased, so it seems that the noted increase in the population is down to the rubble that went in. So that was a success.
I have kept a watchful eye on the condition of the DSB throughout its life, and particularly after the rubble went in – I was watching for signs of compaction, that is, dark areas appearing in the sand below the rubble. There hasn’t been any indication of any problem.
Though the DSB may assist to an extent with seawater quality, there are two things that have occurred: first I have to make sure that when the grid to the pump area is open during maintenance a fish does not gain entry and eat any inhabitants. Second, when my wife is in bed quietly reading, sometimes I can be found sitting on the floor in the dark, face against the aquarium glass with torch in hand.