Native marine aquaria are pretty scarce. Little information exists on how to be successful in maintaining healthy coldwater marine systems in domestic aquaria.

Hopefully this record of my failures, triumphs and ideas will assist others interested in keeping some of our fascinating, beautiful and often little known sea denizens in aquariums.

Sunday, 20 May 2012

50W LED floodlight

In my seemingly endless search for practical and cost effective solutions to lighgting the aquarium I have tried many different things. My latest experiment will be using a 50W LED floodlight purchased through Amazon for £69.99 (free P&P).

According to the manufacturers description this light is equivalet to 500W halogen, at 'Cool White' a temperature of 6000 - 6500K is good for aquarium viewing and at over 4500 lumens it packs some punch. With an exterior grade housing it will be safe to hang over the tank - looks pretty good so far.
Whilst an (almost?) identical unit can be purchased for around £35 direct from Hong King on EBay, postage at £18 makes this significantly less attaractive. Buying though Amazon does give a certain peace of mind in the event of the unit not living up to expectation or breaking down.

If this lamp passes muster I'll be buying either 3 or 5 more to supplement my Light Panel.

10th June update.....

Unfortunately the lamp was 'warm'. Around the 3000K temperature which is utterly useless to me. I returned it over 2 weeks ago and have yet to either receive a replacement or an indication if they do actually sell a 'cool' lamp (6500K) as advertised or if they dont have a clue what colour temperature even is!
Getting a bit cheesed off!


Todays water temperature at Kimmeridge Bay is a rather cool 11.5C. How important is it to try to keep a native aquarium at a similar seasonal temperature to that found naturally? Most native reefkeepers will settle for an average mean stable temperature. I have usually aimed for 16C, but in the middle of summer this is both expensive and difficult to acheive.

My old chiller seemed to pack up a few months ago. The  reservoir seemed to require almost daily topping up and the unit seemed ineffective. So I found another chiller and yesterday I flushed it out and connected it up. Its a different model from the last one. Same manufacturer but instead of 2 coils it has at least 3 with an additional 'water in' and 'water out port' which seems to circulate reservoir water. Blowing through the 'water in' port didnt produce any flow from the 'water out' port indicating that 'water in' filled the reservoir. Perhaps chilled water served at point of use passed directly through the reservoir?
Anyway - I switched the unit on and began to fill the reservoir. When I reached about 2/3rds of the way to the overflow height the 'water out' port began to pump out. I connected it to the 'water in' port to recirculate it using 10mm Speedfit fittings.
The remaining 3 pairs I connected together to maximise contact time for the pumped aquarium water. The return water is markedly cooler than the tank temperature so its certainly chilling effectively.
However, the new unit has no thermostat. Obviously some form of temperature control needs to be installed and I settled for an STC 1000 at a cost of only £26. With the probe in the display tank - or maybe the 1st stage settlement tank I can use it to control the chiller.

Current aquarium temperature is 13.5C. Warmer than local sea temperature, but still uncomfortably cool when up to my armpit in the tank!

Late summer sea temperatures at Kimmeridge reach a balmy 18C. How practical it will prove to attempt to mimic natural fluctuations remains to be seen. I suspect it will prove too arduous a chore and I will settle again for a mean of about 16. However, it occurs to me that natural cycles are triggered by temperature (amongst other factors) and we should try to replicate this in some way.

edit: 21.05.12 Temperature now 12.3C. Chiller working very well indeed. I fitted the new controller, and its very easy to set, so with reminders I may be able to adjust it say 4 times a year to replicate local sea temperatures.
To suit native reefs a monthly temperature programme would be a rather useful upgrade.....

Wednesday, 16 May 2012


Its been about a year and lighting remains an issue. The LED light panel looks good - but simply doesnt produce enough light for shallow water seaweeds unfortunately. Whilst a considerable improvement on flourescents I am struggling to get anywhere near the amount of light I think I need.

New domestic LEDs are considerably better than those on offer a year or so ago and I'll be adding a few to the light panel to beef things up a bit. Keeping wracks remains an elusive goal. They are fine for a few weeks, but have disappeared over the winter, as have many other green macroalgae species. Red macroalgaes are fine - but green and red filamentous algaes are a nuisance, possibly exacerbated by the lack of grazers due to starfish predation. Perhaps the trend can now be reversed with the removal of the starfish and the introduction of new snails.

Encrusting coralline algae is good, especially on the front of the tank where periodic removal of green algae has eliminated competition. Branching coralline algaes are smothered by hair algae at present.

I'll be watching closely for signs that snail grazing improves overall diversity within the tank, if, as I suspect, it proves to be a major factor, perhaps other macroalgaes will make a comeback.

Tuesday, 15 May 2012

May 2012 Update

OK - its been a while, and there has been a flurry of activity recently what with the good weather and all. Firstly the spiny starfish has eaten everything in the tank that it could catch and algal growth has rocketed smothering every surface to the extent that the front of the tank grows over in a few days.

Today he went to his new home at the Bournemouth Oceanarium.

About 400 snails were introduced over the weekend and have already made great progress in cleaning up. A few more may be needed to get things the way they should be though. No limpets survived the starfish ravages and next trip will hopefully furnish a few.

Today saw a large water change - the 1st in 12 months. Water has remained good over the year despite frequent feeding with NO3 at below 5ppm. A yellowish tinge has been noticed however and a change was long overdue. It seems apparent that the live sand bed does assist in the nitrogen cycle and the experiment can be judged successful by my standards anyway.

Water changes will now be carried out at more regular intervals. The introduction of fresh seawater has many benefits - mineral replacement, plankton introduction and simply the exporting of 'aged' tankwater from the system for a start.

Only 2 2-spot gobies remain. They fall easily to anemone predation. An edible crab about 3" across the carapace and a similar shore crab are often seen. They came in as tiny juveniles and have grown to this size from around 10mm in a year.

The wrasse's and mullet are doing well, growth has been strong and no mortality has been noted.

Snakelocks anemones are doing very well but beadlets have been shrunk. New water usually revives them tremendously. I'll keep an anxious eye out for them. An apparent 'Daisy Anemone', Cereus pedunculatus has appeared in the left hand corner in the sand. It looks similar to a tropical 'mushroom' soft coral.