[BlueAbyss]

Sounds like you are on the right track... that's some low pH! No wonder you had die-off!

Going skimmerless is fine, just make sure you don't skip those water changes. I can almost guarantee that your filter was the main problem here, as it sounds like it was pumping all kinds of bad DOCs into your tank. If you are using ANY sort of filter media, make sure you replace it weekly and keep the canister spotless.

As far as trace elements go, I wouldn't bother. What sort of trace elements did you buy? 'Cause anything that would be depleted that can actually be considered a trace element (ie: NOT calcium, magnesium, or alkalinity) will be replaced with your water changes, and you could easily run into problems dosing 'trace' elements in a small tank, depending on what your salt contains for these. Elements such as strontium, molybdenum, and the like are strongly debated... a few years ago these were considered a 'must', now with better research it is known that the most important are calcium, magnesium, and alkalinity (and a lack of DOCs or generally 'pure' saltwater without a lot of 'junk' in it). I personally would put the bottle of trace elements away and forget I bought it... or give it away.

Sounds like things are looking up! How about starting a build thread or tank journal?