Tank suddenly went all cloudy.


Reefing newb
I wonder if anyone can offer advice please. I have a large 600L tank with 150L sump which has been running OK for a couple of years.

Yesterday I did a water change and clean up of the system in readiness for adding some stock over Christmas. Today the entire tank and sump has gone very cloudy, a whitish haze throughout the tank.

I noted this type of thing on a previous tank when the bristle worms spawned. I do have quite a few bristle worms in the tank though over the past 2 weeks since adding 2 homemade traps have caught and removed over 70 large bristles.

It could have been a bristle worm spawn but I would like other ideas as I don't want to spend a lot on new stock and then find it is something more critical. I carried out another water change today after noting the cloud but have not seen any change since doing it.

Ideas and suggestions please.

Thanks Erin

I used a suction to remove water and clean the sand, removed about 50 Litres. I cleaned my skimmer (not very dirty though) and clean my canister filter which runs taking water from the sump inlet side.

I scraped and cleaned the glass and then replaced the water with RO water doses with salt.

Normal cleaning operation which outside of water top up and simple cleaning I do once every 6 weeks or so.

After the cloudy outbreak which came a day after I did the cleaning I changed about 40 Litres more water and over 24 hours later the water is still somewhat cloudy.

If you messed with the sand bed I'm guessing you stirred up a bunch of crud that had settled there.

Just give it time, it'll clear once the bacteria re-establishes itself.