Extreme nitrate drop from vodka dosing
 

I am in the process of cycling my first saltwater tank (first tank ever actually). It's a 29 gallon tank with a 65G corallife skimmer, reef octopus hang on back reactor, a simple power head and heater. I have 20 pounds of dry rock, 20 pounds of very fine aragonite sand, and a single live rock from petco. I am doing a fishless cycle. I have the reactor loaded with 2 cups of tightly packed carbon(switching to bio pellets once fish have been in the tank for a couple of weeks).

• day 1: When I first set up the tank I attempted to use clear ammonia to start the tank but added way to much; after a 100% water change I dropped a prawn in the tank.
• day 4: Prawn was removed at day 4 with ammonia at 8ppm
• day 8: First positive test for nitrites
• day 10: First positive test for nitrates
• day 15: ammonia dropped to zero, began dosing clear ammonia up to 4ppm daily
• day 23: stopped daily dosing of ammonia. nitrates and nitrites have been greater than 80ppm and 5pmm since day 17.
• day 26: dosed ammonia up to 2ppm to feed bacteria. nitrates greater than 80ppm, nitrites greater than 5pmm
• day 27: dosed 6 drops of 80 proof vodka. tested water 2 hours later. .25pmm NH4, .25ppm NO3, 5.0ppm NO4.

I have not done any water changes since the prawn was added. I tested my water several times to verify my last readings. I did not test the water before I added the vodka. I don't see how it's possible for my nitrates to drop that rapidly. I am assuming that the sudden drop in nitrates and nitrites are associated with the vodka dose. I figure that somehow all of the nutrients were consumed in a matter of hours or the vodka interfered with my tests and gave me bad data. I only added 6 drops of vodka; I am reluctant to correlate these two events. From what I understand vodka dosing should take weeks.

Since I was planning on doing a giant water change once nitrites hit zero I figured I would experiment with vodka dosing; its just a box of rocks right now so I figured there would be no harm. Did I completely screw up my tanks chemistry? Has this happened to anyone else? I am shocked at these results and I have a very hard time believing 6 drops of vodka could have this effect.

Note: There is no light on the tank. 250W metal halide/ T5 combo light arrives tomarrow

To Reef Central

The tank should be fine. Vodka dosing isn't going to cause any harm. Different tanks respond differently to the addition of vodka, but that reduction might be due to the level of nitrite in the water. Nitrite will confuse nitrate test kits, so the nitrate measurement doesn't mean much until the nitrite is gone.

I'd stop dosing ammonia at this point.

So there could have been bacteria present that was keeping nitrates low and the high nitrite reading were giving a false high. Once the nitrite levels dropped the nitrate levels read correctly and the fact that I added vodka today is not related to the sudden drop in levels?

Most likely, yes. Nitrate test kits work by converting part of the nitrate into nitrite, and then measuring the nitrite. So small amounts of nitrite show up as large amounts of nitrate.

Thanks for your help! I guess my tank is cycled now; hopefully everything goes well over the next few days so I can order fish on Monday

This is not related to Reef Chemistry, obviously, but a bit of advice since this is your first aquatic tank, ever.

Go slowly when it comes to stocking, and choose your tank's inhabitants carefully so that you don't pick fish that will rapidly outgrow your tank. For a 29 gallon, this means "nano" fish - cardinal fish, firefish, some of the blenny species, some of the wrasse species (a six-line is a nice, easy-to-keep and entertaining fish). Also realize that the number of fish that you can keep in a 29 gallon saltwater tank is very much lower than an equivalent freshwater tank.

For a tank the size of yours, I would advise not going over 3 2-inch-long fish.

Finally, realize that almost ALL saltwater fish for sale are possibly infected with saltwater ich. This would be especially true for large-volume retailers like Petco. There's lots of posts on RC about how to deal with ich - it'll be well worth your while to read them.

Good luck, and let us know how it goes!

I might suggest that you stop dosing organic carbon to a young tank. You need those nutrients to grow bacteria that will be your friend. Any interference that you provide will need to be paid back in the future, sometimes perhaps with a multiple of that time. Spiking parameters, hair algae, dinos, cyano are all rites of passage and should be welcomed when they come and cheered as they leave.

You didn't permanently screw anything up.

Hopefully you have stopped adding ammonia.

There is no reason to dose carbon to a cycling/recently cycled tank.

Dosing carbon might slow the growth of nitrate-reducing microbes some, but generally, there should be plenty of nitrate to go around. Six drops of vodka isn't going to have much of an effect, and as long as you're willing to continue dosing, whether the non-vodka-consuming microbes can handle the load isn't all that important.

Yes, i stopped dosing ammonia. It turns out I wasn't shaking my nitrate bottles hard enough before testing, I actually had 80 ppm nitrate at the end of the cycle. I did a huge water change today and my nitrates are at about 20 ppm now. No ammonia, no nitrites. Fish arrive tomorrow from liveAquaria. I am going to leave the tank the way it is for now, I am not dosing vodka, and once it seems like everything is fairly stable I am going to switch out the carbon in my media reactor for biopellets. I ended up getting 2 blue reef chromis, a few snails, a wrasse, and a Ocellaris. I read in a few forums today that blue reef chromis will fight and kill each other, liveAquaria recommends maintaining a group for some reason, I suspect that increased feeding frequency may curb this tendency though. I am going to feed pellets in small quantities through out the day using an auto feeder, and feed frozen food once a day for a tottal of five (small) feedings.

I will also never again buy anything out of the tanks at petco; I was talking to the girl who manages the sw tanks at the one by my apartment and she told me one of their systems has a horrible ich infection, on closer inspection they looked liked the fish were rotting so not ich, while both of their systems were covered in diatoms. The few corals they have are smothered in detritus. The rock I bought from them when I first started was exposed to 30+ ppm ammonia and has been in the dark for 25ish days so I hope I don't run into issues from that down the road (it was from the less horrible system at that store where the fish "looked" healthy). Petco should not sell fish. The high turn over rates there prohibit employees from gaining the knowledge and skills required to manage aquariums and the set ups they use are garbage. i don't think they even have a skimmer.

Absolutely no reason to feed 5 times a day for a tank that size no matter how small. Once a day is all you need and only as much as they will eat in about 5 min. I have a 21 gal nano and once a day for the 4 fish I have is lots, you'll end up with algae issues or cyano etc.

The blue reef chromis have inter-species aggression issues; breaking up feeding into several small feedings through out the day may prevent them from fighting. In nature fish do not eat one large meal a day; most fish continuously forage and hunt for food. If food is not available for a prolonged period of time, even though enough food is available over time, it is reasonable that there could be resulting behavior changes like increased aggression.

That's an interesting idea to reduce aggression. Please let us know how your Chromis do! Breaking up the feeding should be fine. I used automated feeders for a while and they were adding food 3 times a day. The fish liked that approach. :)

If my tank didn't have a lid over it I would be feeding 4-5x daily for sure. I miss when I used to just have my auto feeder spin throughout the day and take care of all that for me ;)