Sorry bout the die off, that sucks.
I'm a noob myself. I did a few months of research before starting my reef and here's a few things I learned and managed to avoid over the past month...
- Water turnover should be at least 10x of tank size per hour, so a 20 gallon tank should have a filter and powerheads moving at least 200 gallons per hour.
- You should have at least 1/2 pound of live rock for each gallon of tank space, so in a 20 gallon tank you need a minimum of 10 pounds of live rock
- Avoid using tap water. Use reverse osmosis de-ioinized (RODI) for initial set up. Any water from the tap contains chlorine, arsenic, phosphates, copper, etc - all damaging to the reef. Using treated tap with a chemical additive that claims to 'make tap water safe' is not really safe for a reef tank, perhaps a freshwater, but not reef. I initially used treated tap and, under advice from folks in these forums, I emptied the entire tank and restarted from scratch with RODI.
- Your salinity is high. Remember when doing top-ups you do not use salt water, you use regular (RODI) water - though water evaporates, salt does not. Only use salt water during water changes. I was topping up with salt water and couldn't understand why my salinity/specific gravity was climbing. Then my wife looked at me as if I were an idiot (which is often the case) and refreshed me on the fact that salt doesn't magically disappear.
- CYCLE CYCLE CYCLE - this is probably the most important thing for the new tank. No livestock in tank at all, just salt (RODI) water and live rock. Filters and lights off during the cycle. This whole process can take weeks to complete - during which time you can learn about top-ups, maintaining pH, maintaining temp, etc. I've been referring to the past few weeks as 'Learning how to keep water alive'
When I initially set up my 40 gallon I was confused, as all my reading looked great. A few days later, still no ammonia, everything looked good - it was almost as if the tank had cycled. A guy at the local fish store (LFS) told me that with my live rock and live sand, my tank was probably ready for fish. The good folks in these forums told me otherwise and I listened.
What was happening was that bacteria from the live rock were beginning to die and their decaying bodies were slowly building up, which takes a while. After a full week and a half my ammonia began slowly creeping up. Now, over two weeks in my ammonia level is high enough that anything I had in the tank would be dead right now. It should start decreasing soon as new bacteria eat the dead bacteria and stabilize the tank. I'm hoping the cycle will be complete within the next 2 weeks.
So, if your going to restart, cycle cycle cycle. The entire future of your tank is based on how well you go through the cycling process when its first set up.
- Use these forums extensively. The folks here are fantastic and are happy to lend a hand.
Sorry if I'm stating the obvious. I don't mean to sound demeaning or insulting, I'm just trying to share my noob experiences with you.
Good luck,
Mark