How cycling works. An FYI

[Sk8r]

Always useful to have a clue what's going on...so here's the way it works.

You have salt water, a tank, a sandbed (usually). You have dry rock. You have live rock. Live and dry rock comes in two sorts: holey, and solid: holey is better, the way your own lungs have about the surface area of half a tennis court if flattened. You want that kind of area for your live and dry rock: holey is better. They talk about pounds: you want 1 lb per gallon of tank. But---holey is more bang for the buck. Or for the pound. And I don't 'cook' live rock. [Putting it with no light, just circulation and proper salinity, in a bucket.] I want all the creepy-crawlies it can deliver to my tank: copepods, bristleworms, stomatella and strombus snails, etc, etc. So I get an aiptasia or two: no big deal. The advantages outweigh the problems by far.

You add the dry rock, add the sand, add the water, in that order. You then add the live rock atop: no sense burying that nice rock under sand. You can start a 100 gallon tank with 95 lbs of dry rock and 5 lbs of nice live rock. Saves a lot of money. Takes about 8 weeks to cycle, as opposed to 4 with all live rock.

So. Your rock, dry or live, brought you stuff. If you're lucky the live rock brought you critters all of which are nice. It at least brought you bacteria living in its pores. Yep, you can buy live sand, too, but it's not really worth the hassle. Dry aragonite does quite nicely. (It also brought you phosphate, but that's another story.)

At first some stuff dies off on your live rock: bacteria eat it up. They breed. They spread through the water and colonize all the other rock.

Eventually the tank runs out of dieoff. If you want to help it out, feed a few flakes of fishfood daily. Run your equipment: best you get your temperature squared away as it will be when you have critters and it's not as easy as you might think. Keep the temp within 2 degrees of 80.

Now the bacteria has spread. It's sorting itself into colonies in the sandbed, in the rock. It can't handle all the fishfood, so you get a little ammonia spike. This is a signal you're getting close: it's doing the right thing, but hasn't gone all the way yet.

Keep feeding. That phosphate will probably fuel a bloom of hair algae. It will just have a bloom until it runs out of phosphate. I hope you didn't use tapwater setting up, because tapwater also brings in phosphate. From now on---use ro/di water. Only. Hair algae is a PITA. But---keep feeding that fishfood.

Eventually, you can put food in and it just goes away as a bubble of nitrogen gas. No ammonia. The right kind of bacteria are now in enough numbers to handle 10 flakes of fishfood. Hurrah. You are officially cycled enough to support----snails.

Why not fish? Because snail poo is small, not abundant, and within the ability of this baby sandbed/rock to handle. EVERY snail you add pushes the system just a bit more. All the nutrient in the hair algae (which is pretty nutrient poor) goes back into the water and fuels more hair algae. A very little gets turned into nitrogen gas to bubble to the surface. Eventually you're handling a lot of snails and crabs. You use something like a fuge, Polyfilter, or a GFO reactor to get rid of the phosphate; and you put ONE fish into quarantine.

It's like training for the Olympics: your baby sandbed reaches crisis every time you add a new task---as in, one more snail. Now you're up to ONE FISH. Never 'push' a new or weakened sandbed. Give it a slow climb to bigger challenges. You don't want your sandbed to 'crash', meaning, to be overwhelmed with waste. And never, ever ever ever add antibiotics to your tank: anti-bio-tics mean 'against-life-stuff,' meaning it, yes, kills bacteria. Those same bacteria you just broke your neck breeding and coddling. Worst case, they'd kill every bacterium in the tank and your tank would die. That's why you can't treat diseases in your display tank. That's why quarantine of species that can carry disease and parasites is so important. If a fish is going to die, and spread parasites---let it be in qt, NOT in there with your sandbed---and that goes for your very first fish: fish parasites spend half their lives IN the sandbed and live rock, and will go straight for it, when first they get shed into the water. It takes 8 weeks to starve them out---so you never, ever want to get into that situation. Dip all corals; quarantine all fish; and for the rest, we've never had any trouble with snails and crabs...thank goodness!

By the time you add that first fish, the whole sandbed needs to be full of bacteria. And imho now you should add a few more snails: in this case, true nassarius, which rarely surface: they live under the sand and keep it nice. At any point the current gets to accumulating trash beyond what the sandbed can handle---they slurp it up and distribute it elsewhere.

So you NEVER, EVER, EVER clean a deep sandbed. We have a nice article on that matter, up in the sticky-posts atop this forum. If you have a shallow sandbed, you can do a little cleaning: but best of all, imho, is the deep sandbed well-maintained.

If you have bristleworms, nassarius, and a deep sandbed, and you have one of your older snails for some reason demise out under the rockwork, I assure you, said fat snail will be gone in 24 hours, shell clean as a whistle.