I have a 12000L pond with plants & NO fish. The filter/pump/UV are
appropriately sized & I changed the UV bulb 2 week ago - AND the pond
if
still filled with green gloopy algae.

What more can I do to sort this out?

Help!



where is your pump in relation to filter outlet?

it is in the same side as the return fromthe filter - perhaps I need
tomove
it to the furtherest away point?


how is your pond fed? is it a liner or natural?

its a closed system which & is sealed concrete


is it string algae (blanket weed to UKers)?

well I've never seen blanket weed so I don't know. Its clumpy and goey!


how fast are you pumping it through the UV?

according to the pump it would be at about 4500l/h at the height the
filter
is at.


where is the UV in relationship to pump and filter?

the UV is attached to the filter - it is a heissner unit (filter & UV)


how much sun does your pond get?

it is in full sun (not hat we get much here in the North of the UK)!


for an approx 3000 gallon pond, id expect it to take longer than 2 weeks
to
clear.. also might be worth slowing down the flow through the UV..

I expected a few weeks but it seems to be getting worse!


if its string algae (blanket weed) it will NOT be affected by the UV or
the
Filter (it could however block your pump's impellor)

the flow seems to be the same from the pump but I'll check the impellor


how old is the pond? how long has it been "green slop"?

I inherited the pond with the house about 3 months ago & it has always
been
green but it is getting worse!


recommend shading it a bit if in full sun.. and maybe introducing duck
weed
(and many other floating plants...) to starve the algae of light and use
up
some of the nutrients the algae is feeding off..

I've added marginals & floaters & lilys to help with this


really need a LOT more info to really offer help...

BTW what GPH (LPH) is the pump?

it is a Lotus 7500

what Bio filter media are you using? bio balls (the knobly oplastic type)

what
wattage is the UV? 18W



TIA

Lost



thanks for your help...

Hi Skycatcher...

from the info supplied.. ill see what info I can supply (I'm a relatively
new ponder though, so listen to others too)

so far you seem to be doing things right, if its blanket weed it will be
easy to poke a small bamboo and twist it around it, if it comes out all
binding on the stick its probably blanket weed (only way to remove is either
keep spiralling sticks or to use chemicals (I always advise avoiding
chemicals until a last resort)

your flow rate is WAY too fast over your uv, and id suggest at full sun
(when we do get it) your UV is actually less than half the size it should be
(I have 1000 gallons and advised I need 30W minimum (I've got a 9 watt at
the moment left over from the smaller pond, but when finances allow it will
be going up to a 45W (I always go higher than recommended)

add some oxegenator plants..

get a lettuce, (round type) beat hell out of it in a plastic bag (well
bruise it a lot) and put in a bucket of pond water, when the lettuce starts
looking slimy, introduce the water to the filter (this is called infusoria
(sp) and is a great natural way of getting algae eating "aqua plankton" into
your pond..

id suggest halving the flow to your UV and letting the rest of the flow
create water movement..

your pump is really too small for your pond (to clear it) but ok to keep it
clear once its clear..

the UV will not work well on blanket weed, it will clean "pea soup green
water" but at this size very slowly..

some of this is assumptions, most people say you need to circulate 100%
pond volume per hour (means you need a 12000LPH pump) you (as your in full
sun) need a 18000L Filter and probably a 100W UV

however these are guidelines (and often for people who want to keep Koi and
such)

I think the key here is patience and a few good practice tips

is the filter a "pressurised" filter (below water level) or the "stock tank"
type? (I've never used a pressurised (although may be moving that way in
the spring of next year))

also duck weed (surface plant that breeds like wildfire, covers the surface
(creating shade that kills off the algae)) is a great plant (and when you
want to get rid, just put in some Carp (ghost carp in mine (just the one)
loves the stuff (free food for an age too). but the key problem you have is
the algae so we will do our best to sort this problem first..

BTW I'm in S/E UK and we getting very little sun considering its summer
too..

HTH

Lost