Coldwater marine aquarium Blog 2008 November
November 15 2008
Tank November

Before ozone.

Tank November

After ozone.

Tank November

With pumps on. Also after ozone.


Finally, the ozone project has gotten started. I just got my Sander 100 mg/h Ozonizer from i Germany. Before that I had waited for about two and a half months for such a unit from Webzoo in Norway. They gave me erroneous information about inventory status or delivery times no less than three times during this period. Real professionals. But now I am under way.

Carbon filter for air

My two carbon air filters. (DIYed).

I put up two simple systems to filter both air and water exiting the skimmer, with activated carbon. The air filters consist of 2 pieces of pipe. Near the bottom they are cut off and glued together again with a fine mesh in between. The top sections are filled with carbon. They are stuck to the skimmer lid with the same type of sealant tape used around the double glass. It has the consistency of chewing gum, sticks very well and is airproof. So far they work fine with removing all smell of ozone, in fact all bad smell from the skimmer. I recommend this to anyone who want to get rid of smell from the skimmer. It's simple and cheap. The carbon lasts for a very long time. You don't need aquarium carbon either.

Carbon filter for water

Carbon filter for water.

The filter for the water is an ordinary small carbon filter from Aqua Medic. It is attached to a small "cup", made from pipe, that the skimmer water flows into. Not all skimmer water goes through the carbon filter, a small amount will go up the opening of the cup. But I don't worry. Whatever small amounts of residuals enter the sump will be neutralized by the biomass in the sump or hose before they get back to the tank.

Carbon filter for air

Air filters installed on skimmer lid. I added some more carbon later.

The ORP before starting was 159mV. I set the dial on the ozonizer to 50%, which should give me 25 mg/h because I am not drying the air. The ORP started rising and reached 200 after 24 hours. After 48 hours it was 230. Well, I feel an exclamation is in place here: Wow!!! What an effect!! In 24 hours the water had cleared up so much that it felt like looking into a different tank! The colors feel entirely different. They are there, strong and crisp. This could easily be the best investment I have done in my whole time as a hobbyist. Only two days have gone at the time of writing, and it is a little early to draw conclusions here, but it looks really fine. It is just incredible that there can be such a fantastic solution to a major problem. This could get consequences for how I view other filtration devices, like the skimmer.

Double glass

Adding desiccant

Putting desiccant into the frame.

The temparature is going down and it was time to prepare my double glass solution again. The operation of getting the extra glass sheet out from storage, cleaning it and replacing the sealing bands and silica gel took about one hour. The process was completely painfree. Now I can't use an algae magnet to clean the glass anymore, but there isn't that much algae growing on the glass at this time of the year anyway.

Adding desiccant

Sealing around the outer pane.

Starfish and mussels

Asterias rubens

The starfish is a an Asterias rubens

One of the main developments in the tank is that three of the starfish I have collected as small juveniles the last year are now gaining a considerable size. They are large enough to effectively open and eat mussels now. And they sure are efficient mussel eaters. I have removed at least 60 empty shells the last months. Many of the mussels have probably been very weak at the time they got eaten. There has always been a high die off rate among the mussels. That is not necessarily because there is something wrong with the tank. There is a high constant die off in nature too. I recently checked a mussel bed and found that more than 50% of the mussels were dead. There were even some that had died recently and not yet been emptied by scavengers. The low concentrations of micro algae at this time of the year may cause natural reduction in the populations. I have decided to remove the starfish from the tank as I feel they are too voracious predators. I don't want to constantly add new mussels and remove empty shell. I would like some more stability in the system.

Water changes

I have now stopped getting water from the ocean. Instead I mix 240 liters at a time in my barrel. It just got too stressing with all the dragging of equipment back and forth. I also had flow issues with the hose going from the car into the tank. Sometimes the flow would stop due to air bubbles in the hose. Which required a stressful emptying of a 30 meter hose in the middle of the road to the amusement of neighbours and landlord. I am just too shy for that stuff. My homemade system had some leak issues for a long time. Nothing stresses you more than seeing water start leaking in the car. I fixed those problems, but still I got a bit fed up. So I'll take a break with that system for awhile. Mixing the water myself takes much longer time and is more expensive. But I can do it without even thinking about it as work. It it just another simple househod chore. That makes up for it. To save money I tested if I could use salt sold in ordinary food stores as "sea salt". I tested a sample and found the magnesium reading to be 0 and the calcium reading to be only a fraction of that in natural sea water. Also, the anti caking agents colores the water. Utterly useless in other words.


My big pipefish (Entelurus aequoreus) is still doin well! I have never seen it eating anything, but nevertheless it has not gotten any skinnier. It looks just as healthy as when I got it. So I assume that it is hunting among the algae like the wrasses and rock eels. I haven't gotten any new fish since last update. There are very few candidates among the fish I find in the tidal zone nowadays. Still there are lots of species out there. I just haven't found them.

Wave making

Aquarium Systems Natural Wave

My current wave controller. Three pumps on each of the two outlets in use.

Since I have decided to prioritize algae before sessile animals I have long been thinking about improving the flow. It seems like many algae species would benefit from that. The ideal would of course be a few powerful modern propeller pumps controlled by a fully programmable DC wave controller with soft start. Unfortunately the world isn't that simple. There is not a single propeller pump controller on the market that fulfills my needs. Most of them don't switch off the pumps, they are only adjusted down to 30%. That is useless for me since I need to spin the whole body of water, first in one direction then the other. Pumps working against each other would create turbulent flows that will twist the algae and push them down in the rocks. I really need that slow, gentle back and forth movement. There may be a chinese brand that works with alternating pumps, but those pumps are useless. I've tried maxijet mods: Too noisy and weak. So here I am with good old style powerheads. The Natural Wave simulator that I have today is perfect, except it can only handle 50 watts on each socket which is what I have now. So I just need an old style wave controller that can handle about 100 watts on each socket and turn two circuits on and off alternatingly. Not easy that either. AquaMedic's controller for example, can drive 4 pumps in 9 different configurations, none of which will allow 2 powerheads to work alternatingly! Red Sea will allow alternating powerheads, but won't let you specify interval length. Still I've ordered a Red Sea unit. But if I'll ever get it is an open question. This type of controller is going out of fashion these days. Finally I have found that the Aquatronica aquarium computer allows me to set up what I want. But that is a heavy investment to make. But it may be the only option. The nice thing about the computer is that I could preprogram various wave intensity levels. With the red sea unit I would have to set the waves on and off and regulate intensity manually on a separate switch board that I would have to build myself.

Various algae

The brown one in the middle here is Fucus. They have not done well. This specimen broke off at the holdfast shortly after.

Sargassum muticum

The brown ones are Sargassum muticum. They have multiplied all over the tank from one introduced specimen. A common phenomenon with these algae.

Urticina felina

Look at this beauty (Urticina felina). This one is recently introduced. I hope it grows and keeps its color.

Anemones, Codium fragile

The algae is Codium fragile with a piece of Fucus stuck in it. Specimen is dying. They don't do well in the tank.


I've had this scallop for almost a year. Seems to be doing fine as most of the other scallops. I think it has grown a bit.


Another "spot the crab" picture.

Urticina eques

Urticina eques. The two smallest ones are new.

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