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recommended fishless cycle ppm?

Jan 4, 2006
I am starting the cycle on the big tank and want to do it with ammonium chloride. I have been researching it on the web and am getting different target ammonia levels. Some say spike the tank at 1-2 ppm and some say 3-5 ppm. I do know that I want to cycle for a high bio load of a vulgaris so I am thinking of using the 3-5. I figure that if I happen to get a younger one and it doesnt need the filter capacity -it can't hurt it and will diminish on its own.

I got some ammonium chloride powder from the Tampa Aquarium guys who were helping me out, but I don't know if it will be enough for multiple spikes and to maintain the load for 3 months.

I don't want to buy 2000 damsels and would like to stay away from a conventional livestock cycle all together to minimize the risk of adding disease to a virgin tank. I plan on adding some live rock to the base rock I have, but want to have some choice pieces and don't want to kill them. I was thinking about uncured live rock, but I don't want to spend big bucks and have everything I paid for die.

I talked to my wife about the problem, explained the nitrogen cycle, etc. I told her about the ammonia needed to start the cycle and maintain it. She suggested peeing in it. I laughed :lol: , stopped :shock: , thought about it :hmm: , researched it :read: , and found it plausible. But I can't bring myself to pee in the tank and then adjust the rockwork. :oops:

Has anyone done a fishless cycle using ammonium chloride, what was your target ppm, and how did you maintain the load for 3 months?
I think the biggest problem with using the "house brand" of ammonia would be knowing exactly how much you're adding :smile:

I don't know about using ammonium chloride, but I've heard of people using straight ammonia. It has the benefit of being easy to dose precisely.

I do have a reference that will be helpful if you want to match your cycling bioload to that of your choice octopus:

Boucher-Rodoni, R. & Mangold, K., 1988. Comparative aspects of ammonia excretion in cephalopods. Malacologia, 29(1) p. 145-151.

They compared ammonia excretion between a squid (Loligo forbesi), a cuttle (S. officinalis) and O. vulgaris. They have a figure that's a graph of ammonia versus time. On the y axis are micromoles N (as NH4) per gram body mass. On the x axis is minutes. The linear regression for O. vulgaris is Y = 0.007x + 0.083. r = 0.89 and n = 75.

The mean ammonia excretion rate for an adult O. vulgaris is 13.45 +/- 1.48 micro-moles per gram per day. They fail to report the mass of their test specimens, but assuming you have an octopus that's about a kilogram, you can expect him to excrete about 13450 micromoles or 0.01345 moles N as NH4. That's 0.1883 g N as NH4 or 0.2421 g NH4. Ammonia has a specific gravity of 0.63 g/ml so you should dose about 0.40 mL a day.

That seems a little bit on the low side, so you might want to check my math :smile:

I cycled a tank once using ammonium chloride and silver nitrate I think, worked well enough for 3000 pirannahs!

I'll see if I can look out how much I added!

You could always just cure the rock in your tank as it is but will smell the place down! If you are going to be running a skimmer on the tank then i'd be pretty sure that if the rock had cured for around 6 weeks before hand a skimmer could take care of any remaining waste, you'll probably find that your ceph will eat less in the first few weeks anyway which will help to slowly build up the biological filtration levels!
I ran a cycle using frozen mysis shrimp, and seeded squeezings from my reef tank. All seemed well, so I did a second cycle with ammonium powder. Just as the nitrite was falling and the nitrate rising I was getting bored of staring at a empty tank and wanted to really bump the ammonia rate.

So I went to the coast this weekend with my kids and went cast netting. When on the bridge I told everyone I wanted thier junk fish for a big fish tank. I got all sorts of fish and a couple big blue crabs along with the live shrimp that the kids were using to fish with.

God what a mess they are making.

The shrimp are being killed by the crabs and the fish are eating the dead shrimp leftovers. Gonna run a UV steralizer through it for a little bit when it is all done and I will be able to support a whale.
Well, I'm not going to give such a scientific answer to this one with measurements, etc. But I can tell you that you can cycle your tank by just throwing in there a shrimp from the grocery store and letting it deteriorate all on its own. If it is a bigger tank then just throw more shrimp in there. It will cycle pretty fast that way. I think mine took only around 2-3 weeks to complete the cycle. Of course, my tank was just 46 gallons.

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