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.