What happened to my nitrate level?

[minnow]

Hello,
I hope that someone can help me understand what is happening with a fishless cycle in my 50g. It has been cycling for a few months, (due to a pH crash). When the pH crashed there was about a week and a half when I didn't do anything with the tank. Before the pH crashed it was burning throo 5ppm ammonia, nitrite had spiked and was on the decline and nitrate was off the chart. I was continuing to dose with 5ppm ammonia which maybe caused the pH crash (???). Anyways, I did a nearly full water change to bring pH back up and started over again, using dissolved cuttlefish bone to buffer pH. I dosed with 5ppm ammonia, nitrite spiked again, nitrates came up off the chart again. I was happy to see my colony had survived the lack of attention. I am currently dosing with ~3ppm ammonia and test results after 22-24hrs are showing 0 ammonia, 0 nitrite, and < 5ppm nitrate.
I don't understand where my nitrate has gone. I have done a fishless cycle in a 20g a few years ago, and understand how the process works. I have read the only way to bring down nitrates is through water changes and plants taking it up. There is little to no algae in this tank. Does anyone know what is going on? Is it safe to put fish in there?
Thanks very much, Kathi

20g planted
-11 golden pencilfish
-1 golden algae eater
-2 ghost shrimp

50g planted plan
-school of neon rainbows
-yoyo loaches
-rainbow shark

 

[kyle3]

sounds like your cycle is progressing just fine.

it is a little weird how it crashed but i don't think anything to worry about

i'd keep dosing amonia for a 3 or 4 more days and monitor that nitrate. i'd expect it to spike a bit more dramatically.

if the nitrate stays how it is for a week with no increase or anything odd i'd say start stocking slowly and be sure to monitor your levels carefully.

cheers-K

 

[hmt321]

is the tank heavily planted?

I would think that if you dose 3ppm with ammonia each day and you show
0 ammonia
0 nitrite
5 nitrate

if your nitrate stays the same each day without a water change, than the plants are probably using it up.

I would think that you would show an increasing amount of nitrate, with that amount of ammonia added, hmm.

If you are confident that your test is accurate
than it looks like your fish-less cycle is over,
stock it!!!!!!!!!!!!!



my 2 cents

 

[hmt321]

if the nitrate stays how it is for a week with no increase or anything odd i'd say start stocking slowly and be sure to monitor your levels carefully.

cheers-K

I could be wrong

but i was under the opinion that after a fish-less cycle you should fully stock immediately, I was under the impression that if you can dose 4-5 ppm and have it cycled to nitrate in 24 hours your bio-filter is way bigger than what a 55 gal tank can support. So by stocking the tank to a reasonable level the bio-colonies should starve itself down to a functional level. by stocking slowly, would you not bring the bio-filter to low and it would have to build itself back up each time you add a fish (so you get a mini-cycle)

my 2 cents

 

[dorkfish]

The low nitrate is because you did a large water change and your bacteria had lived through the PH crash. The bacteria should be able to handle the full fish load, that and everything else hmt321 said about the nitrogen cycle was completly corect info.

 

[minnow]

Thanks so much for your opinions. I might have been a little unclear... there are no plants in the tank, as well as no algae. Also, after I did the large water change to increase pH, then dosed with 5ppm my nitrate level did come up again, off the chart... then they seem to have disappeared, (with no second water change). It just seems a little "fishy" to me. (heeheehee). I am continuing to dose with 3ppm ammonia and checking results. (have to wait til payday to get fish anyways...)
Thank-you!

 

[dorkfish]

what is your sustrate, and how deep is it? sounds like denitrifing bacteria is developing in an anerobic(oxygen lacking) plae in your tank, wich is the whole reason why some reef aquarists (myself included) chose to run deep sand beds on thier tanks.

 

[minnow]

Hmmmm, thanks. The substrate is 1/8" gravel, if I spread it evenly over the bottom of the tank (right now there are mounds and divets) it would be about 2" deep. I put about 30 llbs of gravel in the tank, dimensions are 36" l x 18" w x 20" h. I also just did a test for nitrate and am showing about 20ppm 5 hours after dosing. Looks like things might be alright after all. I was wondering about denitrifying bacteria (read about it in the nitrate test booklet). I think I'll be doing some research on that now!