not doing so well

[nobby]

hi all, unfortunatly my tank does not to be doing so well, ive just lost another fish(a small clown), which leaves me with just 1 fish remaining, even the hermits are dying and the corals are looking a little sad.
the tank is 48x15x12.
ph 8.4, alk 4.8, nitrite 0, nitrate 0.
calcium 450ppm.
the tank is about 8 months old.
all the fish that have died have had no signs of disease or injury.
im using about 30lbs of live rock, with a external skimmer and power filter, circulation and surface agitation is by two further powerheads.
i know that ive got a high level of phosphates which im using a phosphate sponge.
is there anything wrong with what im doing so far?
any ideas would be great.
andy

[FishDaddy]

Nobby,
Sorry you are having so much trouble. Have you tested for Ammonia? When you lose an animal it sometimes has a ripple effect in that the decay process triggers an ammonia spike that impacts others.
I would also recheck your Nitrate/Nitrite readings either with a different test kit or have it tested at the LFS.
Are you still using the UV?
I would also make sure that your surface agitation is adequate. In your last post you had a problem with falling pH and this is sometimes associated with lack of oxygen exchange.
For now, I would do a series of 10% water changes every day for 3-5 days and see if this makes a difference. I would discontiue any other additives until the situation stabilizes.
Dick

[Alice]

Do you know what the temprature and the salinity readings are? Sometimes we overlook the basics searching for a cause.

~Alice

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Reefkeeping is my life; I can't afford a hobby too! My specs: www.thereeftank.com/ubb/Forum2/HTML/000029.html

[Pik]

The tank size seems to be.... 55 gallons? or something like that?

How long have you had the clownfish before he died?

Hmmm.. I'm at a loss of what could be wrong.

Also, 30 lbs of LR seems a bit low... maybe you can add more CURED LR? Make sure it's really cured before you add it so that you won't have to go through a mini-cycle.

[nobby]

hi all
thanks for the replies,
im still using the u.v, the temp of the tank is 26c the salinity is 1.022. my ammo levels are 0! all tested with dip strips, liquid tests and my lfs( who i can honestly say have been great through all of this)
im now buffering the water and its stable at 8.4,
im planning to get some more live rock soon,
the fist fish to die was only in the tank for 24 hrs, so not too much of a mystery, but the clown has been there for a month, the other clown seems to be fine( at the moment!!)
im baffled.
thanks for the help so far
andy

[Pik]

What are you using to buffer the water?