Nothing new added to the tank.
Have just done almost 40% water change as Nitrate test a little high. Always have problems with Nitrates, have tried most products to reduce this with water changes. Even run to Nitrate filters but they were always causing problems with bad egg smells as difficult to maintain drip return rate.
Will try larger water changes, normal change is about a 3rd of the tank, will aim for higher.
Have also got some salt, not added any yet, never used salt in the tank before and concerned of problems. whats peoples thoughts on salt, add it only now and again, or after every water change? What are the signs of overdose of salt to look for as never added before?