Pufferpunk;4479963; said:
I run 2 AC 110s & a large Eheim on my 90g discus tank.
I was referring to keeping discus.
I do not see how you could possibly keep nitrate free water with only 40% weekly partials. Especially with high waste-producing fish like rays or other large species, unless housed in massive systems.
As per my sig, WC is dillution!
You have mis read my post
Water changes WITH nitrate free water I.e the water going in does not have nitrate in the new water. I agree that the tank will not be nitrate free.
You are correct that wc is dilution but very different to constant drip.one is a sudden and large change, the other is a slow dilution.
I know you were referring to keeping discuss but this is a Ray forum and I was referring to rays not needing 90% (discuss do not need it either though, there is no scientific reason to change that much, if you can keep dissolved solids low then why change so much.)
My nitrates stay below 40-50ppm based on less than 40% weekly changes and I feed twice per day.
I think ac10 is a hang on the back which to me is a poor way of filtering water and certainly not up to rays...discus maybe...an eheim would be a good back up to a sump but one would not be up to rays either...you might even need over 50% water changes with that setup!