Hi everyone, fish are dying in one aquarium, but not the other.

[ASC]

I'm new to this site but not to having a fresh water tanks. My husband suprised me with 2 new 75 gal. tanks.
I've had a 20 gal and a 40 gal before we moved that were up and running for years. I passed the tanks and fish to a brother. The 2 new tanks have been running for over a year. Here's the crazy part the "blue tank" has no issues healthy happy fish and water. The "white tank" everything dies, fish, plants everything! I have an API testing kit that tests ph, ammonia, nitrates and nitrates. All in a normal range. Each tank has cycled, has same filter, heater etc. I've lost so many fish it's not funny. I've taken water samples to a pet store that specialize in fish. They're stumped as well so now I'm here. Please help me it's gotten bad enough we call the white tank the death tank. Any advice is appreciated, I'm open to any ideas and suggestions. Thanks

 

[Aiken Drum]

What precisely are the water parameters?

What's in one tank that isn't in the other? Eg different fish, different aquascape?

Are the 2 aquariums sat next to each other in the same room or are they separated in different rooms?

How are the fish and plants dying?

Can you post photos of each aquarium?

 

[ASC]

What precisely are the water parameters?

What's in one tank that isn't in the other? Eg different fish, different aquascape?

Are the 2 aquariums sat next to each other in the same room or are they separated in different rooms?

How are the fish and plants dying?

Can you post photos of each aquarium?

Both tanks are in my living room not side by side. I used rock and decor from old functioning tank to help with good bacteria. We started out with 6 Buenos Aires tetra, 6 danios, 6 black widows and a pleco in the white tank and 6 rainbows instead of widows in the blue. No live plants in blue only plastic. We just tested the water in both tanks last night and they were the same. Ph 7.2 range, ammonia 0ppm , nitrate 40ppm, nitrite 0ppm.

I'm new to this site but not to having a fresh water tanks. My husband suprised me with 2 new 75 gal. tanks.
I've had a 20 gal and a 40 gal before we moved that were up and running for years. I passed the tanks and fish to a brother. The 2 new tanks have been running for over a year. Here's the crazy part the "blue tank" has no issues healthy happy fish and water. The "white tank" everything dies, fish, plants everything! I have an API testing kit that tests ph, ammonia, nitrates and nitrates. All in a normal range. Each tank has cycled, has same filter, heater etc. I've lost so many fish it's not funny. I've taken water samples to a pet store that specialize in fish. They're stumped as well so now I'm here. Please help me it's gotten bad enough we call the white tank the death tank. Any advice is appreciated, I'm open to any ideas and suggestions. Thanks

 

[Andy Sager]

Is the white tank closer to an air conditioning or heating vent or the kitchen than the blue one?
BA tetras can be really mean fish. Are they still alive in both tanks?
Your nitrate level is at the top of the acceptable level. While this may not be the cause of the issue, it's something that needs addressing.
Are the ship ornaments ceramic or plastic and made in China? Does the paint on them chip easily?
What is the white substrate made of? ( i.e. Name brand gravel, crushed coral, crushed rock)
Have you checked the hardness (GH) in both tanks?

 

[ASC]

Is the white tank closer to an air conditioning or heating vent or the kitchen than the blue one?
BA tetras can be really mean fish. Are they still alive in both tanks?
Your nitrate level is at the top of the acceptable level. While this may not be the cause of the issue, it's something that needs addressing.
Are the ship ornaments ceramic or plastic and made in China? Does the paint on them chip easily?
What is the white substrate made of? ( i.e. Name brand gravel, crushed coral, crushed rock)
Have you checked the hardness (GH) in both tanks?

The gravel is name brand bought at pets mart, the ship was part of my old tanks and bought at a fish specialty store, no paint is coming off and doesn't chip easily. Nothing is alive in the white tank it's just cycling. I'm addressing the nitrate level. I haven't checked the hardness of the water. Will do this also.
Thanks

 

[Andy Sager]

The gravel is name brand bought at pets mart, the ship was part of my old tanks and bought at a fish specialty store, no paint is coming off and doesn't chip easily. Nothing is alive in the white tank it's just cycling. I'm addressing the nitrate level. I haven't checked the hardness of the water. Will do this also.
Thanks

Okay, there was some bad gravel a while back that if I remember correctly, came from one of the "big box" stores and we found that it was leeching ammonia so I would take a handful sample of the gravel and place in a clean container and add water that has no chloramine in it. Wait 24 hours then test for ammonia.

Regarding the cycling issue, why are you cycling an older established tank? If you are talking about just the nitrates, that's an easy fix with no fish in the tank, do a 100% water change with water that has no nitrate in it and the nitrate issue is gone. It shouldn't come back until you add fish and the biological filter converts their ammonia production into nitrates. That said, if you want to keep the biological filter alive, there needs to be ammonia production in the tank. How long has it been since there was fish in the white tank?