Cloudy Water for 4 days

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Aquarium Advice Newbie
Mar 2, 2021
Should I worry if the cloudy water in my 60L fish tank has not disappeared after 4 days? I have tested the water it is amonia and nitrate free

No its not a new tank, I've had the tank for about 2-3 months but I haven't had any problems with my fishes all of them are still swimming none of them are showing any signs of sickness or dying I've been doing my regular water changes
Cloudy water

The colour is milky white mixed with a little tea colour my fishes show no sign of sickness or difficulty I have matrix as my media and 3 sponge filters so i have no idea if I'm doing it right or wrong
Cloudy white water is usually a biological bloom and is common in newly established tanks. Its probably this, i would still consider a 2 to 3 month old tank to be newly established. It normally clears up on its own after a week or so as the tank settles down and nutrients get into balance.

Tea coloured water is normally caused by tannins in the water, most often being released from driftwood. It clears up on its own after a while when the tannins are exhausted from the source, or activated carbon put in your filter will absorb tannins also.
Thanks Aiken

Thanks Aiken so the cloudiness is harmless and I don't need to be concerned but just incase what happens if it doesn't disappear in a week should I do another water change?
You should be changing some water weekly anyway.

There are various things to look at if it doesnt clear up. It is a sign something isnt right in the tank. Perhaps you are overstocked, perhaps you dont have enough oxygen going into the tank? You say ammonia and nitrate are 0? What about nitrite? 0 nitrate is a sign you arent cycled. You should be seeing some nitrate.

What I don't understand you isn't nitrate and nitrite unhealthy for fish because its fish waste i have looked it up here on the internet both nitrate and nitrite should be zero level NO3 because it stunts their growth and compromises their immune system I don't clean the tank everyday every week i'll run out of quick start and water conditioner I only clean in once every 4 weeks quick start and conditioner are expensive.
Im going to start this by saying im presuming you are freshwater.

Can you post a link or refence something that says nitrate should be zero.

Ammonia and nitrite are harmful to fish. Your cycle turns ammonia into nitrite and nitrite into nitrate. Nitrate is removed through water changes. Plants will take out some nitrate and in a heavily planted and lightly stocked tank its possible to have 0 nitrate, but unlikely. Nitrate levels are fine upto 40ppm in a freshwater environment.

I understand in saltwater, where you have low amounts of fish and large amounts of live rock and anaerobic denitrification going on, very low levels of nitrate are common. Perhaps that what you are looking at? But this level of denitrification is difficult to achieve in freshwater tanks.

If you are seeing 0 nitrate the common causes are.
- You arent cycled. Or
- You are doing the test wrong.
- You are changing large amounts of water and basically testing tap water.
Just forget it

Nitrate levels from 0 – 40 ppm are generally safe for fish. Anything greater than 80 can be toxic.


Yes it’s fresh water this is my second tank I do exactly the same to my first tank even though my fist tank has 4 months into it and it’s clear I think it’s just my anxiety getting to me We are in a very tight long lockdown here in Australia

I am very confident and sure that it’s just blooming bacteria because I haven’t seen any signs of difficulty of swimming breathing no sickness but then again it’s too soon to tell all I know is right now they are swimming and eating just fine I do check on every hour

I don’t have any live rock displays I only have matrix and that’s the media for the filter all my plants and displays are fake
Nitrate levels from 0 – 40 ppm are generally safe for fish. Anything greater than 80 can be toxic.

That doesnt say your nitrate needs to be 0. It says levels between 0 and 40ppm are safe. Nitrate is the end product of your nitrogen cycle, if you arent seeing any nitrate you probably arent cycled. This will be the inbalance i mentioned. As your cycle establishes your biological bloom will clear up.

You should carry on monitoring your water parameters and if you see ammonia or nitrite rise above say 0.5ppm you need to do a water change. I would recommend changing some water every week regardless.
Tannins cause the brownish or yellowish tint of aquarium water. So you should know how to remove tannins from aquarium water: Activated charcoal can be used. It helps to remove the yellowish to brownish color in the aquarium and restore the pH level of the water. Alternatively, Seachem products such as Purigen and Renew can be used to counteract the discolouration effects of tannins.
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