Water parameters

[Smokidean]

ok... I have a 40 gallon tank. And a 5 gallon tank with no filter and 3 goldfish. The 40 gallon is down to 1 tetra. The nitrates in the filtered tank is off the charts. The nitrates in the tank with the goldfish is normal. I don't get it! Please help me! Do I need a new filter for the 40 gallon tank. It's only a couple months old

 

[AdoraBelle Dearheart]

Why would you put a single goldfish in a five gallon, let alone three of them.

I try to be patient with people who do things like that, but come on, dude.

 

[Colin_T]

How often are you doing water changes on the tanks?
How much water do you normally change?
Do you gravel clean the substrate when you do a water change?

Check your tap water for ammonia, nitrite and nitrate.

Check the tank water for ammonia, nitrite and nitrate.
If you have nitrites in the tank water, the nitrate test will pick up nitrite and record it as nitrate, and give you a false reading.

 

[Smokidean]

Why would you put a single goldfish in a five gallon, let alone three of them.

I try to be patient with people who do things like that, but come on, dude.

Temporary while I try to figure out what is wrong with my tank

 

[Smokidean]

How often are you doing water changes on the tanks?
How much water do you normally change?
Do you gravel clean the substrate when you do a water change?

Check your tap water for ammonia, nitrite and nitrate.

Check the tank water for ammonia, nitrite and nitrate.
If you have nitrites in the tank water, the nitrate test will pick up nitrite and record it as nitrate, and give you a false reading.

Change water every other week. Change about 20% in the big tank. Sometimes more. I pay really close attention to the gravel. My tap water is perfect. No nitrites in the tank. Would hard water be the cause?

 

[seangee]

Filters make nitrates. You do not need a new filter - that simply proves its working. It is the responsibility of the fish keeper to remove nitrates from the tank, and the only way to do this is to dilute it. I change 75% of the water in all 4 of my tanks every single week.
If your goldfish normally live in the 40G this should be your absolute minimum water change. To get your nitrates down do a 75% water change. If it is still higher than your tap water do another the next day. Repeat until it is the same level as the tap water.