should i put new water in? im getting it for my baby silver-tipped sharks. what kind and how much salt per gallon should i add? what temperature and nitrate levels are ideal for silver-tips? and what fish make good tank mates for these sharks?

/edit tank is 100 gallons. i added roughly 9 cups of reef crystal salt. letting the four filters run overnight and ill take the water to get sampled at the local aquarium store.

Saw your other post.... So welcome.
I guess I'll be the first to say this... So your getting a tank to put in fish that you know nothing about? Not a good plan. Also your settng up a new tank and it is not yet cycled, also not a good idea.
Unless your leaving out a bunch of info, I would not recommend you buying those sharks for a little while... Or they will all die in a month.

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i filled it up with water when i got it. added 1.4 tablespoons salt / gallon. it has twin 400gph filters so im going to let it cycle for 12 hours, then have multiple water tests. the 20 g tank the sharks are in, got tested today and they said it was high on ammonia or something. what should i do?

how long should i cycle the filters. theyre pretty powerful filters for a 100g. it was setup as a sichlid breeding tank originally

Cycling has nothing to do with how long you've let the filter run.
Cycling has to do with the nitrogen cycle.
Search nitrogen cycle, and read up on that. There are a few ways to do it, most people suggest... The Fishless Cycle
If it was set up as a Cichlid tank was it all emptied and cleaned?

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"Buddha in your tank"

Get some Glo-fish they love to eat sharks Do some research before just jumping in even those with tanks set-up for months have some issues. AND WHY KILL YOUR FISH

will do. water was changed but i left his sand in it. the only other fish i have is a baby plecco. i was supposed to pick up a 115 with fish but someone made an offer i couldnt matc, but i ended up getting this 100g tank for the same price.

How many of those Shark Catfish do you have? It gets pretty big, you might overstock the 100 gallon with just one or two of them.

Did you read up on the nitrogen cycle? You can cycle your brackish tank with mollies if you acclimate them properly, they can survive in brackish water.

Don't keep the Pleco in brackish water.

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i have three of them. i read up on the nitrogen cycles. unfortunately both of my tanks are going through that. are the ammonium and nitrite levels going to be more concentrated in the small tank or larger tank? i'm about to run to the store to get the water from the 100g checked.

You should buy your own test kit
Not sure about you question of more concentrated.... It's the sane thing no mater what size tank.

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"Buddha in your tank"

why buy my own test kit when the store down the street does free tests for me. my question was: the 100g tank is five times bigger than the old one. if ammonia is a by-product of fish waste, wouldn't the larger tank make the ammonia less concentrated?

Ok so I wanna say that I'm not trying to sound mean here, but honest.
Having your own test kit is definitly a more than a convinience. At the very least at the odd chance you can't get to the fish store. Or while cycling you need daily checks at the minimum. When doing weekly water changes, many times testing requires multiple daily checks, or if any another problem arises.... It's just a typical investment.
Also I'm concerned that a LFS that would sell you fish your not ready for will be giving you the best advise on water readings.
If youve read up on the nitrogen cycle you'd know that the ammonia level is relative to the bio load in a tank. Wether it's 5 gallons or 500 it's going through the same cycle, your going to read the same ppm.
If you start out wrong you'll have nothing but trouble.
If you got the tank and it was freshly drained, and the filters didn't get dried out or over rinsed, you would be ok to just add water and put in some fish. But you are also converting it to brackish, so you'll have to cycle for that.
I hope this helps

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"Buddha in your tank"

Just a newbie wasting our time and will be wasting there money and fishes lives