David Saxby's tank has become a thing of legend, featured in magazines and on television it is understandable that it commands such attention, now, UltimateReef is very proud to be amongst those that have witnessed this spectacle in the flesh and confirm to you, avid reader, the hype is absolutely warranted. What has been achieved here is no mean feat, a true testament to education, experience and a passion that still after all these years takes the blatant form of a twinkle in David's eyes. As he sat down in his favourite chair, cold beer in hand, the pride in his face tells a story that even the owners of the most humblest of systems can relate to, answering all of our many many questions frankly and honestly, this is what we learnt...

The instant you enter the home of David Saxby you know you're in for something special. As you make your way through the exquisitely decorated hallways you catch a glimpse of the tank through an archway in the dining area. Rounding a corner you find yourself face to face with an enormous window, filled with every colour imaginable. Shimmering in the light are 25+ blue cheeked ghost cardinals hovering over a gonipora of an unprecedented size. Three foot below that on the coral gravel bed is a stunning collection of plate corals and clams, behind which, a pair of crosshatch trigger fish swim in and out of their cavernous home. A very large harlequin shrimp patrols the left wall of the reef and is not fazed by the collection of eyes, now ogling it, noses to the glass.

The vista beyond the cardinals entices you to wander around the corner to see what else you can find and when you do, it's as if the floor is just taken from beneath you. A 40 square foot viewing window, every bit as colourful as the first, takes your breath away like a kidney punch from Foreman. A stunning 3 foot tall gorgonian, reaching out for the surface sways gently in the current, it's main trunks, thicker than a babies arm. Surrounded at the base by trachyphyllias and funghia corals which decorate the bottom of the tank. Despite the sheer size of this system, you'd be hard pushed to spot a space of spare rock. Prior to departure we wondered if it would be nice of us to arrive with frags, what with this being David Saxby's tank, the tank that already has everything, we opted against it. In fairness, I think we chose correctly. Every square inch had been carefully designated already, like prime realty on the Californian coast.

The aquascaping is stunning with numerous caves and archways for the fish to peruse with huge plateaus covered by a variety of corals. Vast columns of coral covered rock explode upwards and outwards making you question just how they stay there. It truly is a sight to behold and never have we been lost for words so quickly.

Another observation worthy of note at this stage is how effortless it all looks. David has worked wonders to make this incredible tank part of the furniture. The external doors and cladding blend in with the rooms decoration and almost look like the whole thing was built from scratch in West London and then an architect and team of builders came in and designed a house around it. All the doors and fascia have been extensively sound proofed meaning that this slice of the ocean intrudes on nothing other than the eyes. Many people have built wondrous reef tanks in the past but never, in our opinion, has one looked so at home in its surroundings as this one, we could have sat there all night drinking beer and staring dreamily, of course, I'm sure that after too long David would have quite rightly called security on us or something but the fact remains, David's lounge is an incredible place to be.

With a surface area of 4.5 square metres and a depth of 48" the tank requires a substantial amount of light, to ensure more than adequate lighting for growth and illumination, David uses a mixture of Metal Halides and T5's.

There are 6x Giesemann D-D MEGA-D units which contain 1x 400w 14kK and 1x 400w 21kK lamps under the same reflector. This unit, initially inspired and developed by David, is a relatively new and innovative unit that delivers a perfect blend of the blue and white spectrums whilst allowing each to be controlled individually.

There are 8x D-D Razor Units each with 1x Aquablue Plus T5 and 1x Actinic Pure T5 tubes.

The mixture of lighting offers approximately 1100 watts per metre square. To be honest we were amazed and somewhat surprised when the Metal Halides were switched off to see the T5's holding their own at 48'' deep. Colours remained vibrant and had the halides been off when we arrived, I doubt we would have noticed.

There are no moonlights on the tank through the night however an external lamp is dimmed and left on to provide a little illumination throughout the dark hours.

Photo-period:
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12:00 - T5's on
14:00 - 21kK Metal Halides on
15:00 - 14kK Metal Halides on
21:45 - 14kK Metal Halides off
23:00 - 21kK Metal Halides off
23:30 - T5's off

Closed loops within the tank provide the water movement. There are 11 Deltec HLP external pumps using electronic actuated ball valves to provide the alternating flow. An interesting factor here is that whilst the rule of thumb for turnover within SPS tanks is at least 30x there is only approximately 14x turnover within this system. As you can see from the pictures, the system in no way suffers for this.

The closed loops are drilled in the bottom of the tank and David considers this to be a weakness within the system, and it's a weakness he wouldn't repeat should he set up another. That aside, it's a system that appears to be working extremely well, rock and coral colonies hide any evidence of pipework and only the alternating direction of swaying corals give away that something is happening. In front of one such outlet is a rock cave within which a single tubastraea sun coral spore landed and has since become a multi polyped colony, making the most of the surging flow.

The sump rooms are approximately 40 meters away and on the same level as the tank. Because of this, and because of the huge transfer rate needed, gravity cannot be employed to move water between them. Instead two more Deltec HLP external pumps are used in conjunction with float switches ensuring a constant transfer rate. One pumps to the sump room, the other back to the tank via a 40mm flexi pipe though the ceiling and above the tank, all pipework is hidden from sight.

Despite the huge scale of this system it's based on the same principles that a lot of us employ on our tanks - lots of light, lots of live rock and lots of skimming.

There are three skimmers operating on this system, a Deltec AP1006, an AP1004 and a TS1064. The TS1064 is positioned in the last sump next to the return section so that any water that hasn't yet been passed through one of the other skimmers is caught by this one. The AP1006 and the AP1004 require minimal attention as both have self flushing, self cleaning heads installed. The AP1004 has been modified at source to accommodate the recirculation pumps to the front for ease of maintenance without having to remove the skimmer from its purpose built cupboard.

There is no way of knowing just how much live rock is in this tank suffice to say it's a lot and it was all shipped direct from the Red Sea to David's tank. Despite the huge structure created with the rock it's very open allowing water to flow in and around it.

In addition to the skimming and live rock there is also a 100 gallon refugium containing a variety of macro algea's and mangroves. To help minimise the pH swing the refugium is reverse lit using 4x 54w Aquablue Plus T5 tubes.

There are also two large Deltec Rowa-phos reactors which keep the phosphate level undetectable. To combat nitrates there is a large Deltec nitrate filter which is fed a 130ml mixture of vodka and RO water each day via a peristaltic pump. The mixture is 1 part vodka, 3 parts RO - David initially tried Methanol but found his tangs developed red spots after a few days so he switched to a good quality vodka and has not looked back! The current nitrate level for the system was at 5ppm however following our visit David was installing a second nitrate filter which he hoped would reduce this down to an undetectable level. Most of us would be more than happy to maintain 5ppm nitrate, just another example of how David strives for perfection, even when he appears to already have it.

As with most large systems heating is rarely required but for the rare occasion when it is, there's an array of 8 standard glass tube 300w heaters controlled by the IKS control system.

Cooling large tanks is usually an issue and it's no different with this one. David maintains a stable tank temperature between 24.7 - 25.0 degrees Celsius with two large Deltec ECO coolers which are mounted outside, undercover, in the courtyard leading to the sump rooms. Providing you can mount or vent the ECO coolers outside they are a very cost effective method of cooling tanks. There is also a chiller in line but only on the hottest of summer days is this required. Assisting the ECO coolers, and mounted above the tank, is a split evaporator cooler which keeps the air temperature relatively cool, so despite the huge number of lights they do not have any impact on the water temperature.

David is of the philosophy that doubling up on equipment prevents complete failure which is why each piece of equipment is backed up by a second one or similar item. Wise words considering how us reefers are, in the main, jinxed. On this system no expense has been spared but the same philosophy can be implemented on any size system with proper planning.

David favours a balanced method of maintaining levels within his tank. The main calcium suppliment is provided by a large Deltec calcium reactor and he also doses Calcium Chloride, Sodium Bi-carbonate, Magnesium Chloride and Magnesium Sulphate to ensure that these levels are maintened in the correct relative proportions.

To control and maintain the system there are 3 separate IKS Aquastar PRO computers, the first one is next to the tank in the first skimmer cupboard and the other two are in the sump rooms across the courtyard. Each IKS independently maintains the equipment within its region, for example the one nearest the tank monitors and maintains the temperature, the lights and the water movement where as the one closest to the large water vats maintains pH, ORP and the nitrate reactor.

Whether it's home made or a professional system such as the IKS, control technology is invaluable when it comes to maintaining, operating and safeguarding these delicate environments and David has used the tools at hand to maintain that all important stability that we all invest so much time in trying to achieve.

Keeping over 400 fish healthy and active requires a lot of food. The tank is fed throughout the day with a mixture of foods and feeding techniques. There are 4 courses of frozen food, 3 servings of 9 cubes and the last in the evening with 6 cubes. The cubes are placed directly into a feeding container fixed in a corner of the tank. Simplicity is the key here as the container is the bottom of a plastic bottle with many small holes drilled into it. As the food thaws it sinks from the container and is gently distributed to the patiently waiting fish, well kind of, the bigger fish have sussed that if you attack the holes you get fed a lot quicker, still, plenty remains for those patiently waiting below.

In addition to the frozen food there is approximately half a netful of live river shrimp added to the tank for the numerous triggerfish, we did ask David how many shrimp that was, quite rightly, he questioned as to whether we expected him to count a net full of live shrimp, suffice to say, in our professional opinions we believe the number to be 'lots'.

Romaine lettuce is added for the herbivores, that's a whole Romaine lettuce a day. The use of lettuce is an on going discussion but there's no denying the vibrant, colourful and spotless appearance of the fish. The sheer size of the blue spot Vlamingi is testament to this system working. A couple of feet long and heavier than a Volkswagen, this is not a fish unhappy with its diet.

Despite what you might think, every part of this tank has been designed, implemented and maintained by David. It would be fair to assume that he may require help given the sheer volume, after all, the tank is 4 foot deep and stocked to the hilt. When asked how on earth he could possibly maintain the bottom of the tank, given its depth and the fact the top is about 7 foot from the floor, David produced a modified step ladder (padding taped around the top) and a set of tongs so long we reckon we could easily reach the beer fridge from the sofa if we got a pair.

A 700 gallon water change is made every four weeks which is approximately 20% of the total system volume and it takes 4-5 days to perform this change. A water change of this magnitude is not just a case of dragging a couple of barrels in front of the tank and swapping the water between them! David has a series of tanks, that are in-line, which are isolated from the system. They're drained and refilled with fresh RO water over the course of 36-48 hours. David then adds a 50:50 mixture of Instant Ocean and Reef Crystals salt that is circulated for 24 hours at 15 degrees Celsius until it reaches 1.027 S.G. At this point heat is then applied for another day until it's bought down to 1.025 S.G. at 25 degrees Celsius. A refractometer is used to test the S.G. and double checks this using a lab grade floating hydrometer to ensure the refractometer is calibrated correctly. When David is happy with the levels of the freshly made water he releases the water slowly into the system by bringing the tanks back on-line.

David uses Salifert test kits to test the levels in his system. He usually does this every 2-3 days to ensure he's aware of any changes in the system, this also enables him to make any minute adjustments to keep the levels at their optimum. Like many of us, David believes that slow and gradual is the way to the effect change in any system and without regular testing this can't be done.

Approximately every six weeks the Rowa-phos is removed from the reactors. This is done on a staggered timetable to ensure that fresh Rowa-phos is added to the system every 3 weeks.

The life within this system is truly something to behold. The variety is not of this world, personally, having seen many many private and professional systems, we doubt such livestock co-exists in any other place in the world. It matters not whether your favourite flavour is fish, whether you are an SPS elitist, LPS lover, or a mistress to the simple softie this system has something for everyone.

Approximately 400 fish from a variety of groups: Angelfish (Dwarf), Anthias, Basslets, Blennies, Cardinalfish, Clownfish, Chromis and Damselfish, Dragonets, Gobies, Hogfish, Jawfish, Rabbitfish, Surgeonfish, Triggerfish and Wrasse.

Hard Corals: Acanthastrea sp., Acropora sp., Alveopora sp., Blasstomussa sp., Catalaphyllia sp., Caulastrea sp., Echinophyllia sp., Euphylia sp., Exaesa sp., Favia sp., Funghia sp., Goniopora sp., Heliopora sp., Hydnophora sp., Leptoseris sp., Lobophyllia sp., Millepora sp., Montipora sp., Montrastrea sp., Pachyseris sp., Pavona sp., Platygyra sp., Plerogyra sp., Pocillopora sp., Porities sp., Scolymia sp., Stylophora sp., Trachyphylia sp., Tubastraea sp., Turbinaria sp.

Soft corals: Actiniaria sp, Cladiella sp., Clavularia sp., Parazoanthus sp., Porifera sp, Sinularia sp, Tubipora sp., Xenia sp., Zoantharia sp.

As mentioned before David has a lovely large harlequin shrimp fed solely on breeding Asterina stars. Luckily for us he has taken residence where he is best visible, unlike the pair of very large ghost shrimp. David handed us a dirty great mag-lite and said "take a look under that cave over there" inside appeared to be a scene from some nasty sci-fi film. Large claws all turned to point at the light as the ghost shrimp stared us down with their beady eyes. We have to be honest here, we grew scared pretty quickly and didn't stare for too long but as an educated guess they appeared to be in excess of 6 inches, not dissimilar to large boxing shrimp only completely white, I suspect this is where the name derives from.

By now, dear reader, you have probably surmised that we were a little more than impressed with this system. On the way up to David's, whilst being kindly chauffeured by Martin Lakin, we pondered about what we were about to come face to face with. We had seen the pictures, watched the video, read the articles and heard the hype but is it possible that it was all too much. Had we over excited ourselves too much prior to arrival? Like a kid who's been promised to see Disney Land, waited all year for the family holiday then when they got there, realised they could clearly see Mickey Mouse's zips and even spotted Donald Duck having a crafty cigarette behind one of the many gift shops. Within seconds of crossing David's threshold it was clear to everyone we truly had just entered the Magic Kingdom. You can keep your cartoons Walt, we've just found the land where dreams really do come true...

We owe an immense debt of gratitude to David and his family who during Christmas week, made us feel more than at home, taking the time to show us every last little piece of the jigsaw that makes up this wonderful system and telling us honestly and frankly how it all fits together.

Thanks too goes out to Martin Lakin who without which, we may never have been able to see this spectacle. He arranged it all for us and even drove us up there, for this we are extremely grateful.

And finally thanks also to you avid reader, if it were not for UltimateReef and its membership, we would never have found ourselves in such a position to be able to illustrate with pictures this system for you. We hope that our humble words have animated our experiences enough for you to be able to imagine, just what it was like, to see David Saxby's tank.

Please leave your comments and questions on the Tank of the Month thread at UltimateReef.com.