need tank cycle help

I have a 50 gallon truvue integrated wet/dry filter tank. It's been cycling for about 5 weeks and at present the nitrites are 'off the scale' in concentration. I did a 50% water change on it to attempt to lower nitrites which barely made a difference. It was spiked in nitrites for a couple weeks before water change. The cycling fish in tank at present are 8 healthy 1 inch Danios and 3 healthy feeder goldfish at 1-2 inches. Temp of water is 78 degrees. I have 1 inch of large rock gravel in tank. The sump is on high setting. I also have a powerhead on other side of where water is pumped back into tank. I thoroughly cleaned this tank before use ,however, it was originally a used salt water tank i bought. Could any trace salinity be affecting the bacterial process? If I could get tank past the nitrite spike I'd be all set to add my bass to it. Any help would be greatly appreciated. Thanks.

I thoroughly cleaned this tank before use ,however, it was originally a used salt water tank i bought. Could any trace salinity be affecting the bacterial process?

No. That's not something you need to worry about.

I can't figure out the cycling thing for the life of me. When I moved my filter was established. When I set my tank up in my new place all was good. I also added a HOB with a bio-wheel and a sponge on the intake for extra bio-filtration capability. I went from having very low ammonia and very low nitrites and nitrates. Now I have high ammonia and no nitrites or nitrates. I gave up on checking it. Fish and inverts are fine. That's all I care about.

Edited by lozgod, 17 February 2010 - 09:32 PM.

This is extremely common - I saw it nearly every week in the shop.

The answer was usually: You're overfeeding - I have found that many (I'd really almost say "most") people feed far too much food and far too often. Wet-dry filters are notorious for a slow build-up of detritus, which usually leads to chronically high nitrates over time. Since your ammonia and/or nitrites are high, you'll eventually cycle the tank and have this exact condition with high nitrates that are difficult to dilute and control at a low level.

I don't think I've ever seen a fish starve to death (except Moorish Idols), but I've seen hundreds of tanks that were overfed.

During a cycle, I'd feed those dudes every 2nd (or 3rd) day and only feed small amounts - if you dump flakes in there or brine shrimp, etc. they should be eating almost all of it before it floats into the gravel, over the overflow box, etc.

More food = more crap, more uneaten food = more crap building up in your wet-dry/gravel bed.

Like a miracle the nitrites dropped to zero in less than a day it seems. I am thrilled I can now put my bass in an appropriate living condition. Nitrates show about 15 ppm. Is that an ok level to have?

Yes, 15 is okay. Different species of fish have differing tolerances to nitrates, but that should be low enough for any fish. I'm happy if I can keep my tanks below 25.

Yep. Any pet store where you get your fish is lucky to keep nitrates below 100ppm. Your tank will the best thing they've ever experienced!

Thanks for the help. I'm new to the fish keeping but thanks to all of you I'm getting much better at it. Many thanks.

This is why I haven't used a test kit since George the 1st was pres.
I learned working retail, people fixate on test kits and chemical addition. Constantly checking test kits and making adjustments causes a roller coaster effect.

Better to observe the fish and animals and look and smell of H2O. Being totally comfortable with understanding the nitrogen cycle gives confidence which allows a hands off no meddling policy. Let the bugs do their work.

In this case, were it me, I'd conclude the standard cycle time is coming up and bugs should be established, especially if mature filter media was used. The cycle fish are all alive and if not gasping, breathing hard and/or scratching, the time is coming to declare the tank cycled.

Get the nitrification cycle established, stock reasonably, don't over feed and do H2O changes and you can virtually wipe nitrates off the list of tank worries forever. Not ammonia or nitrite mind you, just the nitrate.
Get some healthy plants growing and never even think the word "Nitrate" again.

Disclaimer: I know conventional wisdom in the pet lit and online is; this species or that are "sensitive" to nitrates.
While I don't discount the scientists' lab tests, I've just never seen a case where you could use nitrate as a smokin gun for some fish stress or loss.
In my experience and unhumble opinion, a reasonably stocked, moderately fed tank with healthy nitrification cycle and regular H2O changes will just not get to a worrisome level. In a planted tank, fergetaboutit.

Edited by mikez, 26 February 2010 - 07:23 AM.

Solid advice. Floating plants seem to be the best in my experience for keeping nitrates at bey. So if you don't want to worry about substrate and ferts, etc. then get yourself some hornwort, and frogbit. You can also go the driftwood with java moss and java fern as well. Mine is getting established really well and it look awesome. My plants are various vallernsia, elodea, ludwiga repens, hornwort, java moss, java fern, frogbit and duckweed. Duckweed gets a bad rap because of it's reproduction rate but in reality it's easy to manage, very hardy, and some fish will eat it as a supplement to their standard diet.