Brown water

[sadiefish]

I have a 165 litre tank with no fish or live plants in it. When I do a water change the water removed is dark brown.
The water appears clear in the tank. Algae is present and then it all disappears.
Am nervous about adding any fish. Parameters are all ideal.

 

[Aiken Drum]

Can you take a photo of the water in your aquarium and what a glass of it looks like when you are removing it?

What are your water parameters in numbers?

 

[Andy Sager]

Do you have any woods or botanicals in the tank that are leaking tannins?