How do you fix the nitrate, nitrite, total hardness, total alkalinity, and pH levels in a freshwater fish tank?

Nitrate - Change more more water. Aim for a level under 30ppm.

Nitrite - The water changes will also help this temporarily, but it suggests an issue with your filtering or nitrogen cycle. As the nitrate is high, that would indicate that the tank is cycled, but maybe does not have enough filtering, or too many fish. Nitrite should all be converted into nitrate by the filter system, then you get rid of that by changing the water. Check the ammonia level as well, it MUST be zero, especially with the pH that high. A high pH makes ammonia more toxic to fish.

Hardness / alkalinity - This is caused by you having "hard" tap water. Lots of dissolved minerals. There is nothing you can add to fix this, you need to take something out of the water. Usual method is to use Reverse Osmosis filtered water. If you mix R/O and tap water at say 50/50 ratio, you will get water with a 150ppm hardness. Or whatever ratios to get the hardness you want. If you go down this track, you need to mix ALL the water you use in the tank to keep things stable.

Ph - That's high because the water is hard, the dissolved minerals are alkaline and bring the pH up. Don't be tempted to use products like pH down, it's just battery acid. The resulting water will still be hard, just now it's got battery acid in it, and the pH wont be stable anyway.

A better option is to choose fish that actually prefer hard water. African Cichlids or Mollies are common choices there.

Ian

in case you have 4 goldies i'm assuming you have an adequate tank length, of a minimum of 50+ gallons as goldfish require 10-15 gallons according to fish. I additionally propose a filter out that handles double the ability of your tank. I even have 4 goldies in a fifty 5 gallon with a one hundred ten gallon rated filter out. without an adequate tank and filtration device you're putting your self up for sick and dying fish. Is your tank cycled? A cycling tank must be examined another day. A cycled tank could be examined as quickly as a week. All fish vendors ought to have a drop try equipment handy for pH, ammonia, nitrites, nitrates and hardness/softness. Goldfish require cooler water of 60-seventy 5 F. They require alkaline water, it is the pH and because a 7.0 is impartial they require a pH of seven.2-7.8. you will could desire to confirm you get a equipment with a 'severe variety' pH try for this. The ammonia desires to be 0 ppm, nitrites 0 ppm and nitrates under 20 ppm. If any of those are off it may reason stress, ailment or maybe dying. the only thank you to maximum suitable water high quality subject concerns is with water alterations...50% emergency alterations in extreme circumstances with 20-25% on a daily basis or another day till the difficulty is corrected. you additionally can use Kordon's AmQuel Plus to detoxify any ammonia or nitrites in the water so as that the fish are not getting sick yet use this with warning in a cycling tank when you consider which you would be neutralizing it and not allowing the nitrogen cycle to end. good success.

water changes.

10percent every other day or 25percent per week.

when you clean the tank, dont scrub off the biofilm. (light brown slime that forms in your filter/on rocks/plants etc.) dont confuse with algae.

that ph is pretty high.. if it stays that high, get a bottle of ph lowering solution from the pet store or aquarium shop, and follow the directions. you should aim for 7.

Best and easyiest way: change a quater of the water once a week for 4 weeks.