done a tap water test nitrate came out at 40ppm/and the tank water as well came out the same as the tap water. done water change on sunday just gone is this ok or not
40ppm isn't ideal, but if that's what your tap water is, your tank isn't going to be lower (unless you have A LOT of plants).
Most of us do water changes once a week. The trick to make sure you do them often enough that the nitrates aren't building up more than you're getting rid of them.