Never trust your reef to anyone else's water.

It doesn't matter if you only have a nano tank, an RO/DI is a must have piece of equipment. Make your own water and mix your own saltwater. A decent ro/di filter is the same price as 2-4 nice corals. Wait on the corals and get some insurance with the ro/di.

Refractometers and ro/di's are absolutely fuckin essential in this hobby.

I agree with Schigara, cuz I was buying my salt water from my LFS and they told me they were using premium reef salt. I went in a few weeks ago and I saw a guy mixing it with regular Instant Ocean. So, now I'm mixing my own, but I get my RO water from another LFS who gives it out for free. I tested it the first few times to make sure it was real RO. Anyways, the next step is to buy my own RO/DI filter. Good luck

i have been getting RO water from the culligan dispenser at wamart for many months now , 33 cents a gallon, and i have a tub with a heater,powerhead and a thermometer in it, i keep 3 gallons mixing at all times 1.so i always have a quick change if needed. 2.i don't like drying out and rewetting the powerhead all the time i was useing a swing arm hydrometer and then got a refractometer off ebay for 40 bucks and holy crap is it right on.............i will neve use a swing arm again and like others have stated i would never trust anyone else to mix or supply my water...if i f*ck up my tank, its all on me if someone else does.....thers an ass woopin commin some where .....lol

sorry for the lose man.........i think something was added accidently to your water......even if you did a regular 10-20% chane with tap water an established tank shouldn't go sterile in 24 hours ....did somoene dump some chem in the mix at the LFS or something like that? tragic lose but interesting situation

Boss

I agree with mixing your own saltwater. Whoever told you that "perfect" salinity is 1.020 is offbase, IMHO. Natural seawater is more like 1.026 or 35ppt.
There's nothing wrong with Instant Ocean - you'll just need to supplement to grow corals... If you have fish only, you won't need to do anything. Buy your RO/DI from a reputable LFS until you can afford your own RO/DI filter.
Before you put another live animal in a tank, I recommend that you purchase the following:
1.) PH meter w/ calibration liquid
2.) TDS meter for verifying RO/DI water is ZERO total dissolved solids.
3.) Portable refractometer for measuring salinity (specific gravity).
4.) High quality saltwater test kits for CA, ALK, MG and PO4. (Salifert is good)
5.) Standard Test kit to measure ammonia, nitrite and nitrate

Test, test, test. Assume that your live rock will cycle again after a tank crash. Wait until ammonia, nitires and nitrate are zero. After the LR is stable, then you can introduce CUC. If they survive, you can gradually start reintroducing livestock and coral... slowly, one at a time, testing your water between each addition.
It's a tough hobby, especially when outside sources muck up your best efforts to maintain a high quality aquarium...
I feel for you. Been there done that...didn't get a T-shirt.
LL