http://forum.aqua-fish.net/ A forum devoted to aquarium fish, plants, techniques and fish keeping as a whole. en http://forum.aqua-fish.net/?topic=water-hardness-#1 Maybe a silly question, but anyway... I’m not changing any water in my tank (50 litres), since I’m only adding what’s evaporated. Is water hardness of higher values if man does like I do? Basically, evaporated water doesn’t contain any Calcium, so it remains in the tank. That’s why the hardness level should increase as time goes by. Will it stop? Any ideas? Thanks! original post: December 22, 2006, 3:38 pm anonymous 2008-05-01 http://forum.aqua-fish.net/?topic=water-hardness-#2 Theories say that the hardness level should increase each time you add new water. However, the hardness value usually gets stable after some time. There are processes which do so in stable aquariums. ;) Nic anonymous 2008-05-01 http://forum.aqua-fish.net/?topic=water-hardness-#3 If you don’t change water on a regular basis, it could turn to decay and very acidic environment in your tank. Of course, I don’t recommend you this way of making the water more acidic anonymous 2008-05-01 http://forum.aqua-fish.net/?topic=water-hardness-#4 My opinion is that hardness will be go up and pH go up too. If pH will be around 8,0 is bad. I do not know how big aquarium you have, but change 30 percent of water every 2 weeks could not be a catastrophe for you. Wampa 2008-05-01 http://forum.aqua-fish.net/?topic=water-hardness-#5 Hi guys , I’m adding evaporated water too and my tanks do well. It has been more than 2.5 years since I exchanged water the last time. It’s interesting that all fish do well (especially bristlenose catfish http://www.aqua-fish.net/show.php?what=fish&cur_lang=2&id=108). In my experience, water hardness isn’t a big problem if it helps fish to be healthy . On the other hand, your tank has 50 litres only and this could be a problem. Usually, more larger tank means much more stable conditions. I’m not sure if stable chemistry could remain in a 50 litres tank. Let us know how it goes . jan 2008-05-01 http://forum.aqua-fish.net/?topic=water-hardness-#6 there is only so much calcium that the water can hold anyway.Once the upper limit has been reached water can precipitate calcium deposits into the water.I have never been brave enough not to do water changes but I know a lot of people that don't. mickey 2008-06-09