Haha, I don't think that I would waste my time doing exactly 30% lol I remember when I was doing freshwater I would just eyeball about a third and that was good enough for me lol.
Wow a full cup in just a day, shows how much crap was floating around raising your ammonia levels. What kinda skimmer you got?
And also could you test the water and check out the levels to see if that ammonia is on its way down.
PS - that was a 20% change but I don't think that it matters...
In desperate need of help, but very excited to learn. I have tasted the world of aquariums and now I'm hooked.
Here is what I have now...
maxijet 900 powerhead
100W (maybe 150W) heater, but heating isnt a prob
1.5 inches of crushed coral
some decoration stuff including a couple peices of old dried coral.) Not sure if it is real to be honest...
Crappy lights that I am going to rebuild, just for come flourescents