Entry 10 - It's been a while, but it's a big 'un!

I’d definitely planned not to go another full week without an update to this, but this time I do actually have an excuse other than laziness. The major project last week was building the tank for the trial phase. It’s pretty hard to get hold of large, cheap, good quality fish tanks on any commercial kind of scale out here, so we build them. In a kind of Ikea tribute they arrive in flatpack and then have to be glued together, a far more involved process than I’d thought, the trial tank is a 400 litre beast made from 5 large pieces of acrylic and 5 smaller ones that act as braces to the main structure. Each one of these pieces needs every edge sanding down to a shiny smoothness, a process that requires two grades of sandpaper. In addition the edges that will be exposed when the whole thing’s together are softened off using a router to avoid any sharp corners in the final tank. Just doing this sanding took the guys the best part of last week. The pieces are then glued together using solvent, this is actually a pretty quick process as a solid bond is achieved in just a few minutes, but everything needs to be lined up and clamped pretty precisely before the solvent is injected onto the joint, it’s a one chance only effort! I’ll never wonder why large fish tanks cost so much again! It’s worth mentioning here that we’ll have around about 170 tanks in the seahorse ‘farm’ when it’s complete, these will also be arriving in flat pack form.

Anyway, whilst the tank was being built we set up the sump for the trial system so the water could start cycling through. I’ll deconstruct that last sentence for those of you who aren’t aficionados of aquariums and their design (pretty much all readers I’m guessing!) Sumps are basically extra tank spaces attached to the main (commonly referred to as display) tank and are a major part of any large aquarium system. They fill two primary roles, the first of which is to provide a space where the unsightly filtration hardware can go. The second is to increase the volume of water in the system, broadly speaking (and to paraphrase my old housemate James) more water is more better. This is because larger volumes of water are innately more buffered against pretty much any form of change, be it physical (temperature would be the main culprit here) or chemical (nutrient levels, pH etc.). For our trial system the cosmetic aspects are relatively unimportant as it’s sited in the corner of the warehouse, however the biological filtration is being accomplished with live rock fragments, and these are all sited in the sump, if they were in the display tank there’s be no room for anything else! I’m well aware that in trying to explain one fairly simple sentence I have so far written one rather large paragraph, explained half the original sentence and introduced two new terms. Don’t worry – we’ll get there, especially as water cycling, biological filtration and live rock are all pretty closely linked. Still, time for a new paragraph I think.

So, water cycling. I think I’ll go over biological filtration first. As fish etc. live they produce ammonia. This isn’t a problem in the massive volume of ocean they normally inhabit (marine biologist here, if it ain’t in saltwater it don’t count) as it is quickly diluted and used up in a series of biological reactions. However, if you were to put a fish into a tank with brand new and totally clean water this ammonia would quickly build up, killing the fish. Luckily there are a whole range of bacteria that will quite happily live on this ammonia, converting it to nitrite. Unluckily this is also toxic to fish. If we had a tank with just these bacteria the fish would live a bit longer as nitrite is a bit less toxic, but it still wouldn’t last long. Yet again bacteria come to the rescue here, another subset of the microscopic world lives off the nitrite, this time converting it to nitrate. Nitrate is far less of a problem, and can be successfully kept below harmful levels through regular water changes. Biological filtration essentially involves providing a large surface area for these bacteria to do their thing on. Water cycling is allowing the bacteria to build up, this process starts off with the introduction of something living to provide the ammonia, the bacteria just turn up! It takes a few weeks, during which the ammonia, nitrite and nitrate levels all balance out, after which you can introduce your fish. We used live rock as our way to introduce living material, quite simply live rock is rock taken straight out the sea, with all its associated flora and fauna.

I think that’s all the explanation needed of all that lot, stick something in the comments if you’re really that interested! The net result of all that is this:

The two grey tanks are the sump, the tall stack behind is a massively oversized protein skimmer (another important bit of filtration kit that uses lots of tiny bubbles to extract any charged proteins from the water, again, comment if you’re interested), the light is a fluorescent tube set up with special reef lighting on it and the tank is, well, the tank. The two guys are Baya and Tom, who actually put the tank together.

You’re probably wondering why there’s a close up on a pipe. Tthis is the inlet, quite an important bit of the tank. Seahorses aren’t the strongest of swimmers so it’s important to keep the flow in any one place fairly low. However, in order to maintain water quality in the tank there needs to be quite a high flow. In order to balance these two out we’ve designed the inlet as above. This allows for a high overall flow whilst preventing any particularly strong jets of water, additionally the outflows can be pointed in all directions, keeping the flow in the tank nicely variable.

We’ve placed rocks with algae on in the tank; this algae (if it stays alive) will hopefully perform two functions. The first of these is nutrient export, the algae uses nitrate to grow, locking it away. If the algae population takes off in the tank it can be periodically extracted, providing another route whereby nitrate levels can be kept down. The second is to act as a holdfast for the seahorses, the aquatic version of a hitching post.

We’re waiting on some water testing kits to arrive before introducing fish of any sort. These will allow us to flag up any water quality issues before sending any unwitting animal to its death! I’m hoping at least some of you have picked up on a glaring omission from the blog so far, namely seahorses themselves. This has been our first major stumbling block! It turns out they’re pretty tricky little buggers to catch. I spent today out with the divers looking for them, but the resident experts seem to think we’ll be better off waiting for neap tides, as this is when they’re seen more often. These kick in next week, so watch this space.

In short, the decent excuse for such a long delay in publishing this entry is because I was waiting to get a tank sorted out so I could show you some pictures!

In other happenings, the building’s taking a bit more shape, as you can see here they’re starting to put the shuttering up for the main beams, we may even have a ground floor in a week or two! It’s slowed down a bit though as the heavens have done a pretty good job of opening in the last week or so, it’s not quite a monsoon but there’s a hell of a lot of water coming down.

Panto rehearsals are coming along well; the director was in the UK last week and returned with a cracking supply of wigs. Mine’s a lovely thing, a wee bit like a judges wig. It’s crazy sweaty though, I’m pretty glad I’m not on stage for too long very often, give my head a chance to breathe!

Think that’s it for this instalment. I hope you found it enjoyable and a wee bit informative, thanks for reading