Coldwater marine aquarium Blog 2007 May
24 May 2007

Just a small status update

Wohoo, glass is in the tank! The final step of the tank build was done yesterday. So now it only needs to cure for a week or so and then it's done. All in all I am happy with the way the tank worked out. It is strong, decorative, the right size. If it is waterproof too it would be great ;-).

Glass is in

Man, that's one ugly silicone seal :-D! But strong!

I just saw a TV program about boat builders here in my region. A group that I really liked were these guys: Dolvik. They build classic racing boats from mahogany and epoxy. It was really awesome to see how the work was done. I felt that I had something in common with these professionals. After a stressing day's work of staining and applying epoxy one of the guys was asked if he was satisfied with the result. "You're never satisfied", he said, then added: "But it wasn't completely bad either". Thats exactly how I feel too when looking at my tank! I think that is the best feeling you can achieve, there and then, with anything you do by yourself. Especially if it involves surface coating. Perfect just doesn't exist. There are always 100s of things you could have done better. But then again, that it not what others see. They see the one nice result you achieved.

So now it's just to fill it up right..?!


Working on the cabinet.

Oh no, plenty of work left.

I am now hard at work with the closet for the tank. It will match the tank in color. It is made from 2x4s and plywood. Lots of screws and glue to get a very stiff structure. I paint it with regular interior grade oil paint. When designing I was careful to make sure that the fasteners, screws and glue, don't carry any vertical load. I see amateurs making that mistake all the time. If you look at professional woodwork they never let fasteners carry vertical load. The idea should be that if no sideways forces were in place then the carrying structure should be able to stand by istelf without fasteners.


Notice that it is constructed so that if the plywood, screws and glue were removed the load carrying 2x4s would be able to stand, and carry full vertical load by themselves.

I found it impossible to get the lengths of the pieces so exact that every standing 2x4 would carry its part of the load. Actually I figured that only 3 or 4 would carry any weight. I solved this by hammering in thin sheets of wood in the cracks. Hope that gets at least half of the 12 standing 2x4s to carry load. I'd hate to use 12 2x4 and then have a plywood sheet and some glue carrying half the tank. Or hearing cracking sounds as the tank is filled, from glued wood being ripped apart. Not that it would be dangerous or anything. It's just that I would feel so silly ;-P.

Then I need a large closet for the sump, refugium, skimmer, pumps, electricity etc. This will be an Ikea closet, reinforced on the inside with 2x4s. Possibly sound insulated too. I need a tall closet because I want the refugium to be higher than the water surface. The point in that is to have an overflow down from the fuge to the main tank so that live plankton doesn't have to go through a pump.


Now it is time to start planning the aquascaping in terms of decoration. Conceptually there will be 3 levels: The first is the lower sand bed. Then there is a rockwork "plateu" reaching out from the back wall to about the middle of the tank, with the height of about 1/3 of the glass. Of course it is a very naturally shaped plateu, with varying height and depth. Finally a rocky background covers the whole back wall. The wall is almost 1.5 m2 so it will take a bit of rock. Luckily the tank can carry any amount of rocks so there are no worries about damage to the tank. The rocks must to a certain degree be glued into modules. I haved tried doing that with silicone before and was not entirely happy. I Will try epoxy this time. Most of the rockwork will be put in place while the tank is dry. So I can relax and take my time with the work. Finding rocks should not be much of a problem since I can collect them from anywhere around here.

Then there is the sand...

I need about 120 liters of it. I am still in the thinking phase as how to do that. I know how to find the type of sand I used for my FW tank. That is the type that Ron Shimek recommends, or at least I think it is. The problem is that this is not live, it is nutrient poor, and most important it seemed to pack very hard and critter undfriendly in my FW tank. So I wonder if this is the right thing. I see in many areas here that coarser sand is heavily populated with animals. Of course, the surface area of such sand is much smaller, and the smaller creatures can not move the individual sand grains. But then again they can freely move about between them. The larger worms move the grains and even swallow them whole. I am making an aparatus to collect bottom samples. Maybe I should take some samples and study them before I decide on which sand to use. Then I must decide on how much live sand to use and how much dry. The dry has the advantage that it doesn't die or rot so I have some time to work with it in the installation phase. The live sand should ideally be collected and put in the tank the same day I add water. I don't think that will be practical with large amounts of sand.

17 May 2007

Progress update

As you can see the tank is nearing completion. Step 3 of the building process, the surface coating, is now done. Putting in the glass is the final step. The glass should arrive sometime next week.

Thoughts about tank content

There will be a 15cm deep sand bed. The tank is custom made and there is a room for a sand bed below the lower edge of the glass. I like live sand because of its vast amout of life. This is really fascinating and gives a feeling of creating a more "genuine" environment. There are even some large creatures in there like mussels and worms. It limits the choice of other animals slightly. Crabs, for example, have a tendency to comb the sand bed for life, so I can't have those. But crabs are difficult anyway. I am still going to try some species of large crustaceans.

Next on the list are filter feeding animals. I'll try out anything I can get of hydroids, sponges, anemones, bristle stars, soft corals, gorgonians, mussels, feather duster worms etc. The food will be made in a manner inspired by Eric Borneman's famous coral food receipe. Shrimps, fish and other seafood run i a blender, then mixed with zooplankton.

I will have algae. I have particularly great hopes regarding kelp. There are about 300 species of macros around here so I'll try anything I can find that seems promising. I think it is important with fast growing macros to compete with the thread algae. Otherwise the latter can cover everything else in the tank an choke it. It seems that keeping the macros growing relatively quickly is important. Fast growth and health lets them defend themselves against epiphytes, to a certain degree. So I'll try CO2 dosing, and maybe also nitrate, phosphate and iron. For other materials water changes will hopefully provide the needed replacements. Water changes will be relatively frequent because growing algae produce toxins for defense.

Thread algae

Thread algae

This picture is from my freshwater tank 2 years ago. This is after pruning!

Thread algae is a real nightmare, and one of the reasons I stopped keeping FW aquarium. I know that they can be a big problem in marine tanks too. A highly lit aquarium seems to be a perfect place for those organisms. I am not sure quite why they take over, but I have a feeling that it is just their great ability to win the nutrient competition. They have this fine ability to just fill the whole volume of water with themselves. Thus, wherever nutriens are produced, the thread algae are there. So they quickly starve the other algae and plans of nutrients. Since they only attach themseves loosely to other organisms they probably don't suffer that much from the latter's defensive chemicals. They are not covering hard surfaces so that snails and other bottomfeeders can chew them down. The ideal herbivore would be some kind of fish that just sucked them up like spaghetti. But I don't think there is anything like that around here.

1 May 2007

Trip to the ocean

There isn't really much to show for regarding the tank. It is coming along nicely, no problem there, but then again it is time consuming work so things are happening slowly. Basically it is waiting for paint to dry now. The inside is painted and 2 of the outside walls too. That leaves 4 sides with 2 layers each so that is about 6 days of work there. Then there is glass work, furniture work etc. Patience...

This time the wind was still, and I visted a beautiful small bay that was almost open to the great ocean. this bay had a thick rich kelp forest made up of the largest species around here, Laminaria Hyperborea. It was really fantastic to sit there in the bright sunlight watching the schools of wrasses.

Sea fog

Har, har! Is it The Black Pearl i spy yonder in the fog?!

Found this skull of a local sheep, a male. They are domestic animals, but living outside all year. Look closely at the tip of the horn closest to the camera. It has grown too close to the eye and penetrated the bone of the eye socket, changing the growth shape of the skull in that place. Looks like the tip of the horn actually touched the eyeball. Poor creature, I wonder if that has been part of the reason for its death.

Sea eagle

Sea eagle. Harassed by a seagull.


Kelp forest


Ple-e-ease, take me to your aquarium!

Suddenly I heard a splashing sound. A beautiful wrasse had somehow managed to get stuck on top of the kelp! I just got to take a picture before it managed to get back in the water again. Weird!

The tidal zone here was amazing. The snails were bigger than anywhere else I have seen. Large groups of anemones were present in any cravice were they could get some shelter from the dehydrating sun and wind.


Beach shrimp in tide pool.


I have seen many of these snails in my life. This is the biggest.

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