I'm quite new to owning fish, we have a 65 liters (14 gallons) tank with 6 minnows, 2 danios, 2 platies and a Hong Kong pleco which has been running for around 1 month.

During this month I have learnt a lot about water chemistry and would like to ask some advice on how to move the water chemistry in the right direction.

The parameters for our tank are:

  • pH: 8.2
  • ammonia: 0.25ppm
  • nitrite: 0.25ppm
  • nitrate: 40 - 60ppm

The parameters for water directly out of our tap are:

  • pH: 7.2
  • ammonia: 0.25ppm
  • nitrite: 0ppm
  • nitrate: 40 - 60ppm

Both tests were acquired using an API Test Kit.

I would like to know how if a pH of 8.2 is within a good range for the fish in our tank (if not what could be done to correct this)? What would be the best cause of action for reducing the nitrate levels in our water? I am guessing that regular water changes won't make much difference to the nitrate levels as they are so high straight from the tap.

So far I have added the following chemicals with water changes: Tetra AquaSafe, Tetra EasyBallance & API Quick Start. The Tetra chemicals have been used since the tank was acquired, the API Quick Start was used during a 25% water change done yesterday.

I have also started replacing the fake aquarium plants with live plants as I have heard that they can help to reduce the nitrate levels in the water.

Is my only/best option to buy bottled water or are there other/more effective solutions?

  • 1
    Your local pet shop should be able to test your water for free, and give you good advice on how to change the PH etc adequately, to what it should be for your water and fish.
    – Aravona
    Commented Jun 5, 2015 at 5:46
  • 1
    @Aravona pets stores are not always a good/reliable source of knowledge. Commented Jun 5, 2015 at 12:49
  • 1
    Related Is distilled or spring water better for fish tanks? Commented Jun 5, 2015 at 12:51
  • @JamesJenkins Oh I'd say they are here (Bucks, UK), we've had an issue with the water in our pond due to the high chalk content we have which killed off all the fish but none of the reptiles, the local pond/fish store were amazing with the information and tests they did for us, they checked PH, content, good/bad bacteria levels. We've had to remove 90% of the water and replace with unfiltered tap water, then use a bio bomb to restart the ecosystem. I think It is still worth going and asking your local expert to test a sample of your water for nothing at the very least.
    – Aravona
    Commented Jun 5, 2015 at 12:56

1 Answer 1


First things first: your tank is not ready to house fish. When setting up a new tank, you need to cycle the water for a few weeks (typically a month or two) so beneficial bacteria can start to grow. These bacteria convert ammonia to nitrite and nitrite (which is toxic to fish) to nitrate.

As long as you are seeing nitrite in your readings, cycling has not been completed.

Normally, when you see measurements like yours, you would immediately do a rather large water change but I wouldn't recommend that because you will not lower your nitrate levels.

What you can do is buy an osmosis device and filter all the water you are going to put in the tank. This will remove all harmful particles and also lower pH.

You can also buy reverse osmosis water (RO water) from your local fish store if they have some.

While those fish can survive in water with a pH that high, it is absolutely not recommended and it will lower their lifespan. Having a pH that high will also result in the creation of more ammonia and as a result nitrite and nitrate. If your water would be slightly acidic (below pH 7.0), creation of ammonia would be inhibited.

My advice would be to find a solution for your tap water first. Having nitrate and ammonia in your tap water means there is something wrong. Maybe there is a dead animal somewhere in the pipes.

Bottled water isn't that great for fish. If you are going to buy bottled water, get RO water from your local fish store. It will probably even be cheaper.

Good luck!

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