Can someone help why my tank is cloudy?

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Aquarium Advice Newbie
Dec 2, 2022
Have a 90 gallon tank, the filter we have a is brand new. Lately our angel fish are either been getting ulcers or algae eaters getting on the angel fish. One of our angel fish just died. The spot on him is a white and fuzzy looking. Below is pictures of the tank and angel fish. We just did a 75% water change yesterday vacuum the gravel put in the chemicals after. Usually in a couple hrs the water is clear but we’re going on 24hrs


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Im assuming your new filter is replacing an older filter, and prior to this it was an established, fully cycled aquarium? If so, when replacing a filter you should be moving your established filter media from your old cycled filter to your new filter.

Its a bacterial bloom. By replacing the filter you have lost denitrifying bacteria which is responsible for your cycle, and a different type of bacteria is proliferating. Rather than consuming ammonia and turning it into nitrate, this different bacteria consumes ammonia resulting in growth until you can see the bacteria in the water. As your cycle re-establishes the ammonia this bacteria is feeding off will get cut off and the bacterial bloom will end.

Do you know your water parameters? From your other posts you have done a few water changes recently, so knowing what they were before these changes would be more useful.

Water changes will remove the nutrients available to the bacterial bloom, but until your cycle re-establishes and denitrifying bacteria outcompetes your bacterial bloom its just a matter of waiting it out.

Do you know how to cycle a tank?
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