This page contains all the tank events from 1 July 2006 to 30 September 2006.
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We borrowed a light meter from Aquatic Fanatics and measured the light levels in the tank from the surface of the water down to the bottom 45 cm below. The meter was calibrated at 5000 Kelvin (daylight is 5800 Kelvin). For the record, the lighting consists of one T5 high-output 39 Watt tube, two T8 30 Watt marine white tubes and one T8 30 Watt marine blue actinic, all 36 inches long and made by Arcadia: so 99 Watts white light plus 30 Watts blue. Note that, since we had to stick the meter into the water, the readings at the top of the tank necessarily don't take into account the effect of the cover glass, which when reasonably clean took another 1500 lux off.
Now, from The Modern Coral Reef Aquarium the average light levels that one might expect on a coral reef at given depths are as follows:
| Depth (metres) | Light Level (lux) |
| Surface | 77420 |
| 5 | 19355 |
| 10 | 10839 |
| 20 | 6194 |
| 100 | 31 |
So our aquarium is at about 15 metres below the surface, which is rather lower than we'd like. To get up to 5 metres we'd need to more than double the light output. The T5 itself seems to be responsible for about 3000 lux and if we make a squeeze we have room for six more of these, so that's 18000 more lux at the surface. Guessing this would look as follows, where the blue line is the current setup and the pink line the planned new setup.
There is also no reflector behind the lights, which would no doubt make a big difference, and the lights are about a year old.
Went to Aquatic Fanatics today and they happened to have a luverly Regal Tang just in. Couldn't resist completing our blueness with it.
We recently bought an amazing four-volume set of books called The Modern Coral Reef Aquarium by Svein A. Fossa and Alf Jacob Nielsen. They are expensive but are packed with useful pictures and information. They also have a very exploratory/open attitude to the hobby: rather than telling you what to do they encourage experimentation and publication of results, making it plain that the amount we know about the oceanosphere, or whatever you call it, is tiddly.
A few things we've learnt so far:
Having seen all these hand-like constructions on the soft corals, we thought we'd take the Mesoscope and do a comparison of the hands on each one. From top-left to bottom:
So it seems that eight fingers, possibly with sub-fingers, is the winning design for soft corals.
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The continued ailing of the Mushroom Coral may be because we've reduced the flow on that side of the tank by splitting the intake to add a feed on the opposite side. To compensate we've teed-in another NewJet 2300 litres/hour pump in the sump to increase the pace. At the same time we bought a purple Gorgonian, viewed here doing nicely in the increased flow.
You can't really see it in the picture, but the Gorgonian has put out tiny eight-fingered hands to capture food from the water flowing past it, hands which open and close rather like the pulse coral's but at a much slower rate. Here's a view of the Gorgonian's hands through the Mesoscope, where you can see that each of the fingers has a further seven mini-fingers.
Finally, being unconvinced of the new Caulerpa we'd bought below, we stocked up with some more of the original form of Caulerpa.
Alice thought it worth posting a photo of the healed-up Toadstool Coral while you can still see the scar.
Because of the high temperatures we had a few weeks ago the original Caulerpa in the sump tank has now all died. We've had to replace it with a slightly different variety of Caulerpa. Note the green bubbly ends to the fronds.
The absence of the previous Caulerpa mat has made it easy to photograph the red algae that has been growing on the pieces of live rock we left in the sump tank.
Also, there is some wavy orange algae that has begun growing more recently. Here it is in a little garden section with some other purple-red algae we think might by Halymenia.
And we appear to have some home-grown Halimeda of our own, looking somewhat like mouldy cornflakes.
The Stomatella Top-shelled Snails that have roamed around the sump tank for ages now have some hardened coralline algae growing on their shells which offers very good camouflage.
Then, again revealed by the lack of undergrowth, there were a number of very very tiny Bivalved Snails, Berthelinia, around 5 mm long when stretched out but with a shell no more than 2 mm in diameter. They have a clam-like two-piece shell with their body emerging from the non-hinged side of the shell. Amazingly delicate creatures. Here's one sitting on the red algae so you can appreciate the scale.
Finally, something I've been wanting to catch on video for a while - the playing of the shrimps. These tiny brine shrimps are the ones we saw earlier on the heater, but here they can be seen in a rather fuzzy video playing on the lip of the old margarine container that we hold the live rock in. They are barely visible as tiny flashes of light.
For the record, the temperature peaked at 29.4 C in the main tank during last week and the most significant ill-effect has been that the Mushroom Coral has closed-up on us. As the temperature is now dropping it seems to be recovering. The Toadstool Coral has now fully healed its gash. The Caulerpa in the sump tank has turned grey through die-off though.
The Blue Linckia showed us its underside tonight. Thought it worth a photo.
The video below shows one of the small cuddly starfish, that came with the live rock, travelling down the tank glass; this one a seven-legged flavour. Notice the tiny tiny feelers checking the way ahead. Fascinating. It is 1 cm long from top to bottom and during this 30 second video it moves about a body length, giving it a speed of 1.2 milli-kilometres per hour or 0.75 milli-miles per hour. This is 17,000 times faster than the 45 nano-miles per hour of the pulse coral (where the movement is not visible to the naked eye). Quite a sprinter. S'pose it's down to all the legs rather than the single foot of the pulse coral. There probably aren't 17,000 legs though, so they must be more muscley as well...
Today we added a water feed into the top right-hand side of the tank. It has a smaller diameter pipe than that feeding into the left-hand side but we're hoping the extra flow will serve to revitalise the Green Star Coral. For the record, here's a picture of it today: notice how it has now peeled away entirely from the lower rocks.
While we're at it, here's another picture of the Toadstool Coral which is back at full spread, though still with a scar.
But, to keep us on our toes, the Mushroom Coral has not been out for the last few days, though is now showing patches of recovery.
Around 10 days since it began ailing and the Toadstool Coral is happy again. Its tentacles are out and the gash on its face is healing nicely. Phew.
Happened to look at our live aquarium fishcam tonight and noticed that, of the day's algal dusting on the front of the glass, there was a lozenge-shaped clear patch. Watching for a short while longer showed that it is the One-spot Fox-face Rabbitfish who has been keeping it clean. Here he/she is in action. You can also see that the Toadstool Coral is showing some signs of recovery in that its tentacles are now beginning to come out.
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The Toadstool Coral has been ailing for the last few days (since before we introduced the new inverts) and has developed a very clear gash in its upper surface. Not sure there's a great deal we can do about it - we live in hope that it will recover. For now, all its tentacles remain firmly retracted.
