Ok, now this post is going to be really techie, feel free to switch off unless you’ve been passionately following our Aquaponics system development. Before we can put fish into the system we need to make sure that the environment they’re going into is safe for them.

This means it needs to have:

  • The right pH – not too high or too low, it seems 6-8 is about right.
  • Enough Oxygen in the water – Trout need more than 5.5 ppm.
  • No ammonia – any ammonia added needs to be converted into Nitrite & Nitrate by the bacteria in the growbeds.
  • The right temperature – for trout this is less than 25°C and warmer than frozen solid!
  • No chlorine or chloramine (often present in tap water)

With that in mind I set about testing the water that we’d just filled the tanks with – Manchester tap water. If you’re interested, you can see the test results below:


 This ammonia level has been reached as a result of me adding a lot of domestic ammonia to the system. This is to kick-start the bacteria that we need in the cycling process.

I’m having a bit of trouble picking the reading on this scale, but think it’s probably in the 1.5 ppm range.

pH testing

This seems to be a nice clear result – between 8.5 and 9. That’s a little high, but apparently can be expected to drop as the system ‘cycles’.

Chlorine / Chloramine levels

I was expecting this to be high as I’d only recently topped the tanks up with tap water, however we get a good reading of 0 ppm, which’ll be fine.

Nitrite Levels

The Nitrite level is 0  which we’d expect at this stage, as the bacteria haven’t really had a chance to get going yet. Once the ‘cycling’ starts to work this should start to climb a little.

Dissolved Oxygen

This is  good result – probably about 14 ppm. As we increase the pumping time the aeration should increase too. It’ll be interesting to see how long we can go without a separate air pump.