because of the nitrates i think (the test that makes your water turn yellow or green?) well the water was a hint of yellow so there was low levels of the stuff and the rest was 'perfect' so we ad to deal with that problem. They said that you should use rain water in your tank, but they bottled it up at the aquatic centre and sold me 25ltres for £2, they said that it should kill off the nitrates and level it all out, apparently all they use in their tanks is rain water and just adjust the water as needed, IE the marine section they add salt, the harder water section of tropical they add rocks and softer water, they add bog wood. i was advised on keeping the water warmer for the duration of cycling and lowering it a couple of days before adding fish to let the temp adjust, so its currently at bang on 30, but feels luke warm to the touch, but the thermomiter reads at 30. All i though i should use was tap water and dechlorinator, i bought a bottle for around £6 and used it whenever iv changed the water (did a water change after 4 days of cycling) and when i soaked the bogwood, i sat it in dechlorinator before putting it into the tank. I was told to do small water changes every 2-3 days to keep the water in good condition etc.