Cold Water Marine Tank experience

3 years ago I set up an 8 ft 200 gallon cold water marine tank and
added 18 months ago a 4ft tank which I divided into
4 compartments and only partially filled.The large tank has a
biological pond filtration system in line with a uv steriliser,a
protein skimmer,4 header pumps for water agitation and a chiller
which maintains the tank at 15 degC.The lighting is 2 off
4ft 38W interpet triplus tubes.The small tank has just a 4ft tube and
a header pump in each compartment agitating and
aerating.I replace 50 gallons of water from the large tank every 3
weeks with fresh sea water from the river crouch.
20 gallons of the 50 from the large tank replaces the 20 gallons in
the 4ft tank.
In large tank I keep snakelocks (brown and green
varieties),plumrose,dahlia,strawberry,daisy,beadlet.
cushion stars,urchins,prawns,ells and 4 shanny fish.
In 4ft I have daisy,gem,sagarta and diadumene cincta.
I feed with frozen pink and brown shrimps,mussels which I collect
from the river and frozen plankton.

I have the following queries and observations regarding the species I
am keeping.

BEADLET. The deep red specimens lose their rich colour and tend
towards pink / brown colouration.WHY ????
DAISY My specimens spit out young regularly but on one
occasion an additional one of significant size appeared
which could only have been the result of longitudinal
fission. IS THIS KNOWN FOR THIS SPECIES.
DIADUMENE CINCTA. I did have a genuine white species.IS THIS
COMMON ????.This species has not been easy to keep
but I am gradually getting there.
SNAKELOCKS small specimens appear to breed small and large
breed large,ARE THEY IN FACT TWO DIFFERENT SPECIES.

SAGARTIA I have read that one of the means of
identifying elegans from trogladyts is that there are no grains of
sand / gravel on the column of the elegans.I
have some species which have the column completely
covered with small gravel particles and
others which often have none but occaSionally have a few.Is it
known that elegans can have some particles
attached to the column.??????
PLUMROSE I find this species shuts down untill it can smell
food in the water when it will open up.The marina
pontoon where I find my specimens is an area
which looks semi polluted.
DAHLIA I did have problems which I have previously
reported, of this species shutting down and difficult to feed.
I reduced the tank temp from 17 to 15 degC and
added localised light shields to darken the area of the
tank that the species were located,this was
suggested by Richard Lord from Guernsey from his diving
experiences.I am glad to say that the
suggestion works most of the time,I just need to improve on the
light shield system.

Unfortunately I have a medical problem with one of my ears which for
most of my life has prevented me from swimming
and a recent 2nd operation has certainly put paid to any ambitions I
might have had to swim in the future.I therefore can
only search for tank samples in relative shallow rockpools.If anybody
out there has any data on where I can find a couple
of specimens of the Trumpet anemone or has any spare specimens of any
anemone not mentioned above that I could
collect I would appreciate it very much.Are there any divers who
could get me a few samples of the jewel anemone please
I will travel anywhere in the UK to collect.
Later in the year I would like to look for some anemone's in the
Plymouth to Penzance area,any recommendations as to
which specific area I should look at.
I have recently joined a local shoresearch initiative set up by Essex
Biodiversity Project and essex wildlife,they intend to
add the marine search info into the national database 'Marine
recorder'.

regards
jim gibson
Burnham On Crouch