Native marine aquaria are pretty scarce. Little information exists on how to be successful in maintaining healthy coldwater marine systems in domestic aquaria.

Hopefully this record of my failures, triumphs and ideas will assist others interested in keeping some of our fascinating, beautiful and often little known sea denizens in aquariums.

Wednesday 10 August 2011

New Tank Update

The new lights arrived today. 45 x 10W LEDs in an attractive aluminium panel with lots of switches and fans. All very professional and impressive. I went to LedAquaReef in New Milton, I found them on EBay. Jon delivered them this morning and helped me to install them. I advised him of what I was trying to acheive and he designed the layout as follows:
5 no. red LED
10 no. blue LED
30 no. 6500K white LED
The reds offer light most useful for boosting photosynthesis and the blues balance it out a bit, without the blues its too pink. The overall effect is very natural to look at, although it is perhaps more attractive to a tropical reefkeepers eye with the reds off. All the colours are independantly controlled and additionally the whites offer 3 different switching combinations.
The light panel is easily capable of lighting an SPS coral reef and should prove sufficient to keep extreme shallow water native marine plants as found in south coast rockpools.
I've re-landscaped the tank, using about 300kG of purbeck stone originally purchased about 6 years ago for my 1st native marine tank (which burst!) and languishing in the garden for the last 5 years or so. I jetwashed it clean and placed it at the back and bottom of the tank, replacing my planted rocks above. In a couple of places the bright, almost white, 'new' stone can be seen. I'm keeping a photo diary to document the colonisation of the new rock. It will be interesting to see how quickly and in what order new species colonise it.
Purbeck stone is ideal for my reef. Its the natural rock of the area where I collect, consisting of the skeletons of marine organisms that died millions of years ago, permeable and with great buffering potential it should perform in a similar fashion to coral base rock.
Today I added 25 cockles from Poole Harbour, with the 100 or so mussels I already have in the tank they will perform an active role in filtration. I feed a cube of frozen rotifers a day to the sprat fry, it is hoped that the mollucs will benefit from this as well. I still plan to get an overhead refugium up and going to allow a constant supply of phytoplankton but in the meanwhile I have decided to place a regular order with a company called PhytoReef, they supply live phytoplankton and rotifers by mail order.
Today I found a rather attractive bright orange sponge growing on a rock as well as a possible jewel anemone. I'll keep an eye on it.
The snakelocks anemones have gron much larger - probably on a diet of 2 spot gobies. Although these fish are freqently found in the same place as snakelocks it seems that they are a rather hapless prey. Despite many hours of watching I have yet to see one actually get caught they have become fewer in number at the same time as the anemones have grown substantially larger. Perhaps they are more easily captured at night?
The Goldsinny, at about 7" long is easily the king of the tank. It has well-developed teeth and has been seen chomping on a small shore crab, although it will take krill it is most easily tempted by a frozen whole mussel in the shell. Whenever we have Moules Mariniere for tea I keep all the open shells in a bag in the freezer. I use a knife to partly open the shell to allow the fish to get inside. If you cut the shell completely in half it tends to fall flat side down with the shell uppermost, so its important to leave the two halves still attached.
All the other fish gather round whilst the wrasse feed hoping for a scrap, the Montagues Blenny dives straight in and takes a bite in typical blenny fashion.
The spider crab is behaving rather oddly. It has been seen tending its abdomen with the tail flap lifted. No eggs are visible and the larger spider crab was released months ago, but I wonder if it is gravid?
The bladderwrack has survived well under the old makeshift light panel although other seaweeds have changed colour from bright yellow green to reddish brown indicating insufficient lighting levels. The new lights should reverse that change.
I have fitted a 4.5W blue LED over the sump, I'm adding shells and some vertical piling type structure to encourage the settlement of squirts, sponges, soft corals etc. I hope that they maight be present as plankton in the water. It may be worth carrying out plankton collection trips to seed the tank further. The skimmer doubtless has removed much of the original plankton, it is producing an enormous amount of foam!
I added a couple of kilos of sintered glass to the settlement tank,, it used to be in the overhead wet/dry filter in my Amazon biotope tank and should help to trap the sediment collected and provide a more stable habitat for the organisms that feed on the detritus that will settle there.

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