Cycling- When is it officially ready for stocking?

[apexi]

I have been cycling my 180g with 150lbs of uncured Fiji LR for the past 3 weeks. I also have 50lbs base rock, 180lbs of CaribSea Aragamax Sugar Sand with about a 2" sand bed depth (no DSB), and salt water using ro/di with Kent Salt, as well as an Octopus NW200 skimmer.

The nitrification cycle seems to be complete as ammonia and nitrite readings have been zero for the past week. My nitrate readings however are at 30-50ppm (hard to tell with my crappy Red Sea test kit-is it dark pink or red...hmmmmm). I'm seeing brown algae starting to grow on the LR and some very small spots on the sand/tank walls. I have done about 30% water changes thus far (3 partial 10% WC over the past day) with no significant change in nitrate readings. I'm thinking it may be due to some detritus that have fallen off the LR and collected on the sand.

My question is, at this stage, do I need to wait further until the denitrification cycle has also been established with anaerobic bacteria to reduce my "high" nitrates below at least 20ppm before adding any livestock to the tank? Almost everything I've come across through online forums seem to suggest that once ammonia and nitrites are down to 0, conduct a 50% water change and begin slowly stocking with some corals, inverts. Since it can take quite some time for the anaerobic bacteria to become established to convert nitrates into nitrogen, most people seem to start slowly stocking after the nitrification cycle is complete while doing regular weekly water changes. I thought this was the norm as well however I'm confused and was hoping I could get some further insight on the matter.

THANKS.

[JediReefer]

Always better to wait. I would give it another week personally. But I am carrazzzah

[dailydriven911]

I agree, I would wait a bit until the nitrates get really low like 10 ppm or as close to 0 as you can get them. It really depends what kind of corals you plan to keep. Some can tolerate higher nitrates than others. If your running a refugium with cheato or similar this will help reduce your nitrates as well. I'm starting up a second tank and I'm in the same boat as you. It sucks but always better to wait.

[jab502]

I would say that if you added a fish or a coral it would probably do fine. The likelyhood of something dieing due to a Nitrate reading of 30 is highly unlikely. But I definitely agree that it would be better to wait. Also, I have found the test strips to be very inaccurate in my tank. I would purchase a better testing kit to truly find out what is the reading is. Adding macro algae to your sump will also quickly do wonders for your nitrate reading.

[adtravels]

strat now just go slow and feed only a minute amount

[Lucky-rc]

IMO I would go ahead and buy my first fish/coral or two...
By the time you take them out of your Q. tank your display tank will be ready.

Lucky

[jeffbrig]

Do as big a water change as you can to reduce nitrate that's accumulated, and start stocking.

The bacteria populations that consume ammonia and nitrite have already peaked in response to the die off of the live rock. That's how you got back to zero on those tests. However, those populations will die off, due to their lack of a food source to sustain the population. When you finally introduce fish, the added waste they produce will cause another small spike while the bacteria populations are growing to handle this increased load. If you add them now, the bacteria are already there and ready to process any additional ammonia source.

[younglcy]

Following along. My tank's been up about 3 weeks too, ammonia is zero, nitrite is close to zero, nitrates and phospate still a little high. Doing water changes as fast as I can make up the new water (RO/DI).

[joelr31]

I would wait and also reduce the sand bed to 1".

[apexi]

Wow thanks for all the replies. I've now done up to 40% water changes over the course of the past 2 days. WC on a 180g is no small chore I have another batch ready to go, which would bring me up to 50%.

I also spent a good amount of time last night trying to siphon out as much detritus as I could. I siphoned out about 15 gallons of water and got lots of it out. Although I got out as much as I could, it seemed to be never ending. I tested for nitrates yet again this morning (must've been like my 7th test I've conducted in the past couple days) and it seems to indicate 25ppm, but it's so difficult to decipher the Red Sea test kit with the subtle shades of color. Is it light purple or light pink, dark pink (20ppm) or red (50ppm), etc...very frustrating to say the least. I think I'll take a sample down to the LFS to have them test it and maybe pickup another test kit while I'm at it.

[Lucky-rc]

TSET KITS ARE FOR REALLY REALLY SMART PEOPLE WHO NEED SOMETHING TO CHALLENGE THEIR BRAIN...lol,lol,lol

I'll just stick with the multiple choice guess.

Lucky

[NealNano]

API test kits are cheap and easy to use. I use them and there is a reef kit to!

[apexi]

Here is the latest update to this story. After taking another sample yesterday morning which read half of what my previous readings were, I said enough was enough. I took a sample of my water into the LFS just to see what was going on with my nitrates. Using the Salifert test kit, the readings were very low, more like 2.5ppm-5ppm max!!

I went home again to test the water again with my kit, and it still looked red or reddish. But I guess in fact the color was supposed to be pink, corresponding to 10ppm on the card, rather than dark pink= 20ppm or red=50ppm. Without seeing the whole range of actual liquid colors upfront, it's almost impossible to know what exactly constitutes red vs pink in the liquid sample compared to the printed color card. This of course resulted in endless hours of frustration and 40% water changes over the past couple days (I guess which never hurts but no easy chore on a 180g).

Anyhow, I guess I'll be picking up some Salifert test kits