I cant believe we have such a thread on professional site like this.
we should all read randy's article on water changed if we havent yet.
what do we do when we change water ?
we dilute nutritions and remove some.
diluting heavy metals which may have build up
removing extra n and p
adding back the lost elements.
pulling solution towards ionic balance state.
replenish the sources for KH, CA, MG, K+ and many more.
so those whos corals look worse after water change are removing too much zooplanktons from water which were the food source of corals, the new salt mixed had different KH, ca, mg levels and shifted ph or ...
and for those who are getting better growth, perhaps the elements which corals took up are limiting its growth and after water change they are back at acceptable levels for coral to grow again, or you have removed n and p making the coral more comfortable.
that being said, we should all ask ourself a really important question before each water change, why ?
for me, 7 G of water change per week on a net total of 100G works perfect. I do water changes to gain back the lost elements, such as iodine, bromide, SI, floride, K+ and many more .. and my corals look more colorfull after water changes. if I do too much water chnge, corals will go pail due to not enough nutritions in tank. and so on ...
