Journal 55L British Rockpool Biotope

[NathanB]

How big is the crab?

Only about 1cm, a little baby! Anything bigger would be awesome but would probably be a bit too destructive.

What type of rock is it? Where did you collect? (So I can get my geology on)
Why locally sourced rocks, but not use sand from the beach too?

Chalk, from a super rocky stretch of beach near the white cliffs of dover. I did have concerns that the rocks would make the water too alkaline but I'm keeping an eye on the ph readings and all is well so far. Also the rockpools where most of the tank's inhabitants came from were all chalk rocks, so I figured using rocks from their natural enviroment couldn't do any harm! but still keeping an eye on ph.

Also I really wanted to use this liverock as it was covered in different algae including a whole lot of purple coralline, lots of little barnacles and all sorts of life on them too so it was great for getting the tank's ecosystem started. And about the sand, I could've definitely used some natural sand but I already had this coral sand, I also liked the white look, made me feel like Im keeping a tropical reef!

Do you have to use a blue light for these?

Nope, all the anemones would most probably be fine under any lighting, especially the beadlets. The only partly photosynthetic species in the tank are the Snakelocks, but with supplementary feeding they should be fine too.

If I collected sea water how long could I store this for? I would keep it aerated, and kept in darkness?

Im not too sure to be honest, I've always used it immediately after collection. But I wouldn't want to use it after more than a week maybe, you never know how much die off you could get from any organisms or phytoplankton in the water, I could imagine that it could go bad with time. But im really not sure

 

[dw1305]

Hi all,

I did have concerns that the rocks would make the water too alkaline but I'm keeping an eye on the ph readings and all is well so far

You are fine, sea water is already <"fully saturated"> with calcium (Ca++) and bicarbonate (HCO3-) ions.

Only about 1cm, a little baby! Anything bigger would be awesome but would probably be a bit too destructive.

I'd assumed it was a baby one.

lots of little barnacles

• <"Netted Dog Whelk"> (Tritia reticulata)
• <"Sting Winkles"> (Ocenebra erinacea)

I might a little concerned about those as well.

cheers Darrel

 

[NathanB]

Hi all,

You are fine, sea water is already <"fully saturated"> with calcium (Ca++) and bicarbonate (HCO3-) ions.

I'd assumed it was a baby one.


I might a little concerned about those as well.

cheers Darrel

The Netted dog whelk is one Im keeping an eye on, but my understanding was that they feed on carrion like dead fish and crustaceans? or in my case, a little bit of prawn. As for the Sting Winkles, im going to have to release them as I wont be able to provide the right food, also the barnacles sadly seemed to disappear and die off a couple of weeks after setting the tank up, not sure if they were predated on, but I guess any filter feeders and bivalves would be difficult to keep, maybe unless dosing some phytoplankton

 

[seedoubleyou]

The Netted dog whelk is one Im keeping an eye on, but my understanding was that they feed on carrion like dead fish and crustaceans? or in my case, a little bit of prawn. As for the Sting Winkles, im going to have to release them as I wont be able to provide the right food, also the barnacles sadly seemed to disappear and die off a couple of weeks after setting the tank up, not sure if they were predated on, but I guess any filter feeders and bivalves would be difficult to keep, maybe unless dosing some phytoplankton

Yeah you’d certainly need a “dirtier” tank to keep filter feeders happy. It’s not impossible as there are plenty kept in the warmer side of the hobby.

 

[NathanB]

Little update for you all,
The tank is doing really well at the moment! A Snakelocks anemone even split in half to multiply, so now I have an extra one! Some algae and brown diatoms are starting make more of an appearance since increasing the light intensity a little for the snakelocks, but I'm happy about that as it means more food for the snails and cushion stars. The rest of the inverts get fed with some sinking shrimp pellets as well as the leftover bits of prawn and mussel that the anemones spit out when they've had enough.

The tank is also very low maintenance, I dont have to constantly moniter salinity levels or pre-mix saltwater, All I do is top up the pump chamber in the back with some cold RO water (Also, would dechlorinated tap be okay?) when it evaporates and clean the front glass every week or two! Everything seems to be thriving so far, there's also lots of baby Beadlet nems popping up all over the rockwork now which is nice to see.

I might go on a mission to collect some amphipods and more chalk gravel soon, also It would be good to add more Purple Topshells too if the algae starts to get to the point where It needs cleaning off by hand, I'd like to get the balance right so that I don't have to touch the glass much if thats possible, but we'll see!

 

[Wookii]

Awesome photos! What are you using to take them?

Do you have many shrimp in there? Do they not have a go at the diatoms?

 

[NathanB]

Awesome photos! What are you using to take them?

Do you have many shrimp in there? Do they not have a go at the diatoms?

Thanks! I have a male & female pair of Common Prawns, they don't seem to touch the algae or at least don't make an impact on it. I have seen them lowering their heads down to the rock to graze but that's all, never on the sand. They seem to be mainly scavengers rather than algae grazers, constantly searching for any meaty foods they can pick at

 

[NathanB]

Awesome photos! What are you using to take them?

Oh and I use an Olympus OM-1 with the Olympus 60mm macro

 

[foxfish]

When I was really into cold water marines, I had several larva rock hardscapes stuck to a perforated plate.
I would place one hardscape in a suitable half tide rock pool and keep one in the tank then swap them around every few months.
The fresh hardscape would hold an amazing amount of life that would appear over a few days often with some very surprising creatures.
However you can expect a certain amount of die off, especially seaweed, I found running a powerful protein skimmer worked wonders and really helped during the change over.
The skimmer would always offer a bit of daily scum but when I did the change over, the skimmer would froth like mad for a couple of days.

 

[seedoubleyou]

Also, would dechlorinated tap be okay?

Sadly not. Too many other elements at play in tap water.
RODI water is best, then any elements that are low would need dosing either separately or using some form of all in one.

At a minimum you should be testing:
Specific gravity - “salinity”
Alkalinity (Dkh) (Mag and Calc should in theory fall inline if Alk is good)
Phosphates (Po4)
Nitrates (No3)

Are there any suitable urchin species for the tank. They’re great cleaners and brilliant for No3.

 

[Bradders]

This is truly a thing of beauty.
(It must be said, I am partial to black and blue tones with accents - but woooah!)

 

[NathanB]

When I was really into cold water marines, I had several larva rock hardscapes stuck to a perforated plate.
I would place one hardscape in a suitable half tide rock pool and keep one in the tank then swap them around every few months.
The fresh hardscape would hold an amazing amount of life that would appear over a few days often with some very surprising creatures.

Now that is a very cool idea.

At a minimum you should be testing:
Specific gravity - “salinity”

I do monitor the salinity regularly, what I should have said was that I no longer have to worry about it being the tiniest bit too high or the tiniest bit too low like I did with my last tropical nano reef. All of the life in the tank is accustomed to fluctuations in the water parameters, I'd also guess that they're especially used to changes in salinity like when rockpools evapourate on a hot summer day, or the opposite like when it rains. However i do need to mention that although these guys can tolerate an extreme or fluctuating enviroment, obviously I do intend on keeping them in a healthy stable one!

Are there any suitable urchin species for the tank

I have seen some people keep urchins in their tanks, we have a few species here so im unsure which I've seen though. I'll try to do more urchin research.

This is truly a thing of beauty

Thanks a lot!

 

[foxfish]

I love this thread, it brings back memories and excitement!
I wish I could find some photos of my old tanks but, I have given it a bit of thought and realise the last cold water marine tank I ran must of been about 27 years ago.
My first attempt would have been as a child, I can clearly remember having a classroom ‘local marine tank’ at junior school and several of my class mates had home tanks too.
These tanks would have just been air powered with no artificial lighting but as long as you stuck to the half tide rule, they would run just fine.
In my early 20s when I still lived at home, I particularly remember my first chilled tank.
I used a small freezer with 25m of coiled hosepipe inside.
I just ran a tiny powerhead from the tank into the coil and back to the tank, my mum went crazy when the quarterly electric bill arrived!
However it worked extremely well and enabled me to collect from low spring tides for the more interesting creatures like juvenile ballan wrasse, pipe fish, Cornish lump suckers etc in fact the choice is huge…..
Unfortunately there were issues with condensation running down the outside of the tank and the noise of the permanently running freezer.
The marine tanks came and went for the next decade or so until I had a bit more money to invest in a titanium chiller (beer chillers did not last)
At that stage of my life I was a very keen diver and fisherman with my own boat, the world was my oyster!
I built a 4’ tank from plywood and fiberglass with insulated sides and back and a double glazed front glass.
The chiller was in the unheated garage and the pipes went through the lounge wall into the garage.
Twin mercury vapour lights, multiple powerheads and a huge 4’ tall skimmer in the garage.
To be honest that tank was a massive commitment and very dominant feature, the water changes were a chore even though I could walk to the beach from my house.
I dont think I would ever go to that extent again but I must say I am feeling very tempted to set up another half tide tank….

 

[NathanB]

I love this thread, it brings back memories and excitement!
I wish I could find some photos of my old tanks but, I have given it a bit of thought and realise the last cold water marine tank I ran must of been about 27 years ago.
My fish attempt would have been as a child, I can clearly remember having a classroom ‘local marine tank’ at junior school and several of my class mate had home tanks too.
These tanks would have just been air powered with no artificial lighting but as long as you stuck to the half tide rule, they would run just fine.
In my early 20s when I still lived at home, I particularly remember my first chilled tank.
I used a small freezer with 25m of coiled hosepipe inside.
I just ran a tiny powerhead from the tank into the coil and back to the tank, my mum went crazy when the quarterly electric bill arrived!
However it worked extremely well and enabled me to collect from low spring tides for the more interesting creatures like juvenile ballan wrasse, pipe fish, Cornish lump suckers etc in fact the choice is huge…..
Unfortunately there were issues with condensation running down the outside of the tank and the noise of the permanently running freezer.
The marine tanks came and went for the next decade or so until I had a bit more money to invest in a titanium chiller (beer chillers did not last)
At that stage of my life I was a very keen diver and fisherman with my own boat, the world was my oyster!
I built a 4’ tank from plywood and fiberglass with insulated sides and back and a double glazed front glass.
The chiller was in the unheated garage and the pipes went through the lounge wall into the garage.
Twin mercury vapour lights, multiple powerheads and a huge 4’ tall skimmer in the garage.
To be honest that tank was a massive commitment and very dominant feature, the water changes were a chore even though I could walk to the beach from my house.
I dont think I would ever go to that extent again but I must say I am feeling very tempted to set up another half tide tank….

That sounds amazing to have a tank that size, I can imagine the excitment of setting it up and having your own boat and being able to dive to collect things! A lot of people go for thick acrylic tanks I think, must help a lot with that condensation you mentioned as well as extra insulation

 

[seedoubleyou]

healthy stable

And this truly is the key in home aquaria. Whilst I appreciate nature, we can never let truly emulate it at home.

I’m looking forward to seeing the tank develop and hoping you manage to add more to it over time. There are some stunning cold water reefs out there and not many hobbyists trying to create them at home.

 

[malik uddin]

You can order natural sea water from the natural seawater company. They also do ro at zero tds. The prices including delivery are very low. I used to keep the water and ro water upto 8 weeks without problems and that's in 25l containers on the balcony without aeration. If you do a 15% water change once a week and only top off with zero tds ro you wont need to worry about much at all,

 

[seedoubleyou]

You can order natural sea water from the natural seawater company. They also do ro at zero tds. The prices including delivery are very low. I used to keep the water and ro water upto 8 weeks without problems and that's in 25l containers on the balcony without aeration. If you do a 15% water change once a week and only top off with zero tds ro you wont need to worry about much at all,

Assuming the water volume of his tank is 55L (after rock and sand it won’t be, but let’s assume). That would be a 8.25L water change each week.

Things may have changed since I used them a few years ago, but minimum order was 50L, so larger water changes would be needed to make it work.
They also do water changes and initial fill, but I believe that’s minimum 300L (and the water is already heated).

My experience of the NSW company. They never missed a single delivery, the driver was a hobbyist too, you can just leave the containers out and they will fill them. (If you forget one day, they will leave filled containers but charge for them).
IMO it’s not the cheapest option. With delivery 50L 4 weekly cost me £27

 

[malik uddin]

You can talk to them and they will sort you out, chances are they already deliver in your area.

 

[NathanB]

A new angle, nice to see the crypts in the background!

I photographed something cool, the Painted Topshell cleaning it's shell with it's foot! You can also see one of the many baby beadlets in the second picture below, there's quite a few dotted around the rocks now. I've also observed something interesting, so far in my experience with keeping our native beadlet anemones, they seem to be very aggressive to each other, stretching their Acrorhagi towards each other when in close contact to sting each other until one moves away. Here's an amazing Timelapse video of that! However I've read that this only occurs amongst unrelated specimens, so it would be interesting to see that with my own eyes, if two related anemones will be peaceful in close proximity. Another thing to note, the beadlets do however seem peaceful when in close proximity with a strawberry anemone, even though the two species are very similar and in the same genus! You can see that with third image below, the beadlet on the left was collected locally to me in Kent, and the strawberry was collected off the coast of Cornwall.



It really is amazing to me to be able to view these sorts of behaviours and learn about these native species. Everything in the aquarium is something that I don't often see in the wild, I only have great memories of finding them whilst rockpooling when I was younger! So I feel especially privileged to be able to see these creatures in own my bedroom.