Nitrates in uncycled tank?

[a sea k]

I have a 210gal tank w/250 gal total capacity that has not finished cycling and already shows 20 ppm of nitrate. I don't think this is normal and would like to get a handle on this problem before it gets out of control.
Her'es what info I have so far. Tank filled on Aug 31, Let circulate and added 230lbs uncured Fiji,Kaelini,Buna branch,also 110lbs cured fiji from local seller on Sept 1.
Test water on Sept 6 Ammonia-0 Nitrite-.03 did not test for nitrate yet
Test water on Sept 9 Ammonia-0 Nitrite-0.1 Nitrate-20 also arranged LR in display and changed 30 gal of water. Also changed filter sock.
Test water on Sept 11 Ammonia-0 Nitrite-0.2 Nitrate-20
Other info- Temp consistent from 78/80 PH 8.1 No lighting 1-2 inches reef sand in display W/D filter with no bioballs onlyfilter pads, 50 gal sump w/ 22gal fuge has LR rubble and 5" oolite, tank drain thru filter sock to sump and skimming w/ ASM G4+ (has been skimming since I filled the tank) No livestock.
I found it surprising to not see any ammo but figured the cured rock was offsetting that. I'm a litlle alarmed at this much nitrate this early(only about 1 week after adding rock) almost forgot, Tank was filled w/ RO water and it tested at 0.
Is this normal? Could the cured rock from the local guy be leaching nitrate into my tank? Should I even be worried at this point?
Any info would be helpful, Thanx,Chris

 

[ophiura]

First, get the reading double checked at the LFS to ensure that it is not a test kit issue. What test kit are you using? Nitrate tests can be tricky at times.
I think the cured rock may have offset the ammonia spike from the uncured, but the end product is still nitrate, and that would accumulate. It takes time to establish the biological aspects that reduce nitrate. Do you have a refugium with macroalgae?
All in all, I would not be extremely concerned. I think you are seeing the end of the cycle...some water changes, and futher maturation of the tank with some macroalgae and establishment of the deep sand bed should help. YOu may never see 0 on nitrates, but I think you will successfully get it reduced from 20.

 

[a sea k]

ophiura, Thankyou for the quick reply. I had to step out for a bit and have just returned.
LFS not so local for me (about 50 miles) but test kits are new salifert just purchased for this tank, I feel it is accurate and agree can be tricky to determine results.
Agree the cured rock helped the ammonia as well but think my nitrate is a little high for only 1 week after the rock was placed in the tank and still wonder if its possible for the cured rock to release nitrate back to my system. I was told the rock came out of a 3 year old system and asked about any infestation or medication used in the system and was told no to both. I do not have any macro in the system yet and did not seed with live sand in the fuge.
Not overly concerned yet, but I surely expected the cycle period to take much longer and wanted to get a handle on the situation before it gets out of control. I would like to avoid water changes during the cycle but it may be needed to control my nitrate levels. Thankyou again for the input, Chris

 

[ophiura]

With that much LR, your cycle may be relatively non-existant.
It is possible with older rock to have an accumulation of detritus in the actual holes of the rock. In this case, it is a good plan just to swish the rock around in some water before placing it in the tank, to try and dislodge any excess organic matter.
Just because your nitrates are at 20 already does not, IMO, mean that they are destined to continue to increase during this period.
When you mentioned your source water tested at zero, was that before or after the addition of salt. If you have not done so, test a fresh batch of salt water to ensure your salt mix is not contributing anything.

 

[a sea k]

As far as the uncured rock I did some aggressive brushing and a dip in 40 ppt salt mix then some serious swishing in 34 ppt salt mix to match my main tank salinity. The cured rock did not get any brushing (it looked fairly clean) but did recieve some swishing in the 34ppt salt mix.
This good news to hear. I will monitor my nitrate levels every 2 to 3 days to see where I'm at.
Source water was from my RO without any salt. Won't have any mixed till thurs but I will test then and see. I use Tropic Marin salt and would be very disappointed if it were the source.

 

[chub]

My numbers almost match yours 55g 50# cured rock 20 uncured and 50# of base rock been running almost 3wks no ammoina 05 nitrites and .20 nitrates as of today , ive tested 3 times with 2 differant kits the numbers almost match each other. I figure my cycle is almost done

 

[a sea k]

The tank circulated only water for 4 weeks before i put the rock in, so the rock was only in the tank for 1 week before the nitrate hit 20. Maybe the tank is almost cycled just way sooner than I ever expected. Guess I'll wait awhile longer and see how things go.