Thanks Peter,
I'm not terribly happy with Tenecor as my top panel started to separate from the sides a month ago. I had to do my own fix (with Weldon 3) which fixed it fine.
BUT, I notified Tenecor and they took their time responding so I had to fix it right away.
By the time they called me, I told them that I did my own quick fix and their "superfast" response was: since I already did my own quick fix, my warranty was now void.
Anyway, that's a whole other story....
Regarding water changes: I don't do any since I added my nitrate filter.
Ammonia and nitrites always stay 0 thanks to my large w/d filter.
Nitrates were 100+ in February. I did my last 200 gallon water change in January. Now, my nitrates are less than 20 and still going down thanks to my nitrate filter which I added in February.
It also has a Phosphate option which I just started so my phosphates are also on their way down (currently off the chart).
My coral skeletons keep the Ph at 8.2 or higher so I never need buffer.
I only add "saltwater" to make up for saltwater that I drain when I empty the canister filters to change the cartridges.