How long should I let a 90Gal tank cycle before introducing fish, Fluval FX5 filter being used?

Question

I'm just setting up a knew 90Gal tank, the guy at the pet store said it would be ok for fish after cycling only 24hrs. I had always thought more like a week, adding little bits of food to induce the nitrogen cycling. I'm trying the Fluval FX5 for this tank, any feed back on this filter. Thanks to all those who answer these questions, your awesome.

Answer 1

Milo,

That is the ultimate question. Each tank is different so to give you a time, it could be 2 weeks or 6 weeks. Once your tank has been running, you need to allow the cycle process to kick in and 24 hours isn't going to do it. If you want to cycle it faster, add a piece of raw fish or shrimp to get it kick started.

Chances are after about a week test your water. What are your readings? two weeks, test the water. If your nitrates and Ammonia, PH are stable, your tank is more than not cycled, however if they are not, you are going to have to wait another week When your water quality readings are all stable, you can start to add fish. Remember do not add too many too quick or it will send your biofilter into space. One to two fish a week or two apart. Patience. I cannot say I have ever used a Fluval FX5, I can only say if it is rated for your tank and filters 3x the tank capasity, you should be fine.

24 hours your tank isn't cycled. To help you understand what is going on in your tank, here is a good link.

http://freshaquarium.about.com/cs/biologicalcycle/a/nitrogencycle.htm

Good luck with the new fish.

Answer 2

I can't imagine who told you to do all of those things. You just uncycled everything. Sorry, but goldfish get way too big to put two in a twenty gallon. If you're getting a fancy goldfish, one can live in a 20 gallon happily, but if you're getting a comet, not even one will do. Anyways, if you plan on doing goldfish, you'll need to have a filter that works to twice the capacity of the tank (meaning one that will keep a 40 gallon tank well cleaned) because goldfish are very dirty. After that, goldfish are generally pretty hardy. Your aquarium isn't going to cycle without an ammonia source, so just add a goldfish. OR you could do a better option, buy a heater, and have a tropical tank. IMO, it's silly to run a 20 gallon tank for one fish.

Answer 3

A tank will not cycle without a source of ammonia. That can be a few fish or something like fish food or a piece of seafood. It can even be a small amount of white or distilled ammonia. You are right, it will take a few weeks to get the tank cycled. Doing it without fish is usually faster as the early ammonia levels can build up higher with no risk to the fish.

I have very little experience with fluval filters, but what little I have has always been positive.

MM

Answer 4

theres no set time on how long it takes a tank to cycle, you'll ned to test for ammonia and nitrites to determin wether its ready for fish.
you need to keep adding the food until you get ammonia readings, when you get these, continue adding the food daily. shortly after you will have nitrite readings. you need to wait until your tank is showing no nitrite and no ammonia readings and these are both toxic to fish and will harm them.
So wait until all your readings are in order and even then i would only add around 3 hardy ish to see how it goes. Like i said there is no time limit, but it will take longer then a week to do this. When i set up my new tank it took 3 weeks, that was with me using bottled pure ammonia (avaliable from most supermarket stores), and using gravel and filter material whish was already seeded with bateria from an already cycled tank. Jus tank your time and be accurate and patient, and you have a healthy aquarium and happy fish. good luck

Answer 5

more than 24 hours.... It really depends on the fish you want to introduce. I usually cycle my tanks by introducing something to get the cycle started. After a couple of days, I introduce my tough catfish... nothing can kill those things. Then after a week of my catfish getting settled I introduce my more delicate fish. I have done this successfully many times, with arowana, discus, and a fresh water sting ray being some of my more sensitive fish.

Answer 6

Ideally, until your first plants are rooted.

But no one ever does