Coldwater marine aquarium Blog 2009 February
February 21 2009

Wave making

Relay unit with contactors

The first attempt with contactors.

One of the things I've been looking into for a long time is how to get more wave action in the tank. As I wrote in the previous update, no propeller pump controllers could do the job. Actually, when I read carefully through the manual for the Tunze multicontroller I found a program that could probably fit my needs. It was called the tidal program. But I finally decided that the 7000 NOK ($1000) price tag, including 2 pumps, was unacceptable. I actually ordered an expensive Aquatronica computer to do the job. But after weeks and weeks of waiting and no delivery, I cancelled it. Finally I came up with a new idea: It was to simply use the old Aquarium systems Natural wave, and install two relays in a box. The Natural wave would then switch on and off the relays instead of the pumps. And the pumps would be connected to the relays. Thus the wave maker would not be directly connected to the pumps and I would not be restricted by its 50 watts limit.

Relay unit with general purpose relays

Second attempt with general purpose relays

I sat down and looked in the catalog of my favourite shop, Clasohlson. I didn't quite know how relays worked at that time. They had something called "general purpose relays", but I didn't undertsand how they worked so I went for two "motor contactors". These are also relays, but big. In fact they were made for up to 10000 Watts. The click when they switched was so loud that I found it unacceptable. So on to the general purpose relays. These were quiet in operation, but a new issue emerged: The disturbances in the cables when the pumps started created som strange effect that made the relay in the wave maker bounce back from time to time. Luckily the solution to that problem was to put the pumps and the wave maker on two different household circuits. The pumps are on my livingroom circuit and the wave maker on the kitchen circuit.

Mounting relay box in cabinet

Mounting relay box in cabinet.

I bought a small electrical encapsulation box with a standard DIN rail in the back. The box is splash proof, which is good for safety, since the relays and connections are completely exposed. There is no water in the upper part of my cabinet, it is strictly a dry zone. But wet hands and accidents do happen, and the more splash protection the better. I drilled 5 holes, for two pump cables, two controller cables, and one mains cable. The holes got waterproof cable bulkheads.

Eheim Compact +3000

New powerful 66 watts wave pump, Eheim Compact +3000

The new pumps are 66 Watts Eheim Compact+ 3000. They work quite well. I clearly see that they give the algae the movement I've been missing all along. It is almost like some of the algae responded to the increased wave action immediately by standing up and being more bushy. The added flow was probably much needed. There is a problem with them though: They make a loud click when turned on, that is every 30 seconds. So I usually keep them off at night. I installed switches on the cables of the large pumps so that I can turn them off easily. I now have 3 modes of waves: Full mode, with 1 66W Eheim and 2 15W MaxiJets on each side. Small waves mode, with only 2 15 Watts MaxiJets on each side. And finally, calm mode, with only one 15W powerhead running continously for mixing.

Relay box in cabinet

Relay box in operation.

Some outdoor shots

Sea eagles

Sea eagles.

I do small collection trips regularly. It is horribly cold to have ones hands in the water in winter. But it is mostly for the nature experience anyway. One day I was lucky to see three sea eagles. They were circling right over my head for a few minutes.

Peace and quiet

Peace and quiet.

Coraline algae in tide pool

Nice coraline algae in tide pool.

Nudibranch eggs

Under this rock I found nudibranchs spawning.

Nice collection location

A nice collection location.


Frozen food

The frozen food in my new mix.

It was time for "cooking" again last month. I have been a bit critical to my own food for awhile. One of the reasons for that is that it is now fairly obvious that I am not able to keep several species of clams. This is most notably the blue mussel Mytilus edulis. But also two species of sand dwelling clams are impossible to keep. The question is of course: What is killing them? The answer is not clear, but I am currently speculating that they are simply starving to death. Perhaps they are adapted to feeding continously on something that there is nothing of in my tank. According to many articles they feed mainly on phytoplankton in nature. There is probably little of that in the tank. I doubt that it is possible to create a good feeding regime with phytoplankton in this tank. So I may not be able to keep these animals. But I would still like to increase the amount of phytoplankton in the diet I am feeding. In the next months I will be looking into growing my own cultures of phytoplankton.

Dry food

The dry food in my new mix, plus phytoplankton contained in liquid.

Until now I have made food based on my own interpretation of the "Borneman mix". Basically it meant running shrimps, shells and fish in the blender and adding some dry food and frozen plankton. I decided that I wanted to go away from the blended food principle and go for a more concentrated product. I just didn't like the watery and gelatinous impression that food gave. I have never been really confident with it as a plankton replacement.

Scale worm

Scale worm

Scale worm

When I lift rocks in the tidal zone I always find bristle worms underneath. I often take some with me. But since they are very shy I rarely see them in the tank. One night I spotted this large one when taking a look with a flashlight. It was about 5 or 6 cm long. Very nice with large clearly visible scales. It certainly did not look underfed!

Knotted wrack

Knotted wrack

Ascophyllum nodosum, with some epiphytes.

This month I decided to end the experiment with knotted wrack (Ascophyllum nodosum). I introduced it last year winter. But it never grew, it just seemed to steadily die off. So I took out the rock with it on, and placed a new rock with some nice red algae in its place.

Metridium senile

Metridium senile. I have many of these. They seem to be growing and thriving. I think they like my new concentrated food mix.

Red algae

Newly caught red algae. They grow, but slowly. Crossing my fingers.

Urticina felina

Urticina felina

Sargassum muticum

Sargassum muticum

Urticina felina

Urticina felina


A newly introduced rock with bryozoa and a nudibranch on it. The nudibranch is about 1 cm long.

Hippolyte varians

Chameleon shrimp (Hippolyte varians), in one of its many disguises. About 2 cm long.

Symphodus melops

The corkwing wrasse (Symphodus melops) blends in with the nice red algae in the background.

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