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CYCLING A TANK , making silica sand live , please read


Aug 21, 2004
I have added about 4 cups of live sand to my silica play sand , sand bed.
Im wanting to knwo how long it takes the bacteria from the live sand to go throught the sand bed,

and also , How much food matter or amonia do I need in the tank fo rit to cycle , As of right now I have a quarter sized piece of shrimp rotting , is this enough to make the 240 gallon cycle ?

hello , thanks for replying

well I have two - 3 striped damsels in the tank , and one recently died, I dont knwo why it did , the other one is fine,
How many damsels DO i need to cycle this tank , without over doign it , I dont want to kill them , that would be cruel
A couple pieces of raw shrimp will be fine as long as there is plenty of stuff for bacteria to grow on. Do you have rock or a wet/dry filter? Check ammonia levels and you should see them start to climb, then you'll know that you have enough load in there. When levels start dropping you'll have the bacteria doing it's job. When ammonia gets back to zero you're ready for fish.
well ,

i threw a freshwater minnow in there to rot , i had some shirmp ,a nd I have one damsel alive in the tank , and have had for 2 days , and I checked the amonia in my tank and its 0 ppm

I have a emperor 400 on the tank , maybe the bio wheels are really getting with it or something

I guesss I could add my lionfish , though I might wait , It woudl be a bummer to loose him when Ive had him this long.

I thought the bacteria grew in the sand as well ?

I know it does on live rock , I have live rock in the tank , but its only about 20 lbs , thats all I can afford righ tnwo
Bacteria will only grow in the sand if you have an under gravel filter I think, if not then it will just become anerobic and need gravel siphoning daily!

Should take at least 3 weeks to fully cycle a tank in my opinion, ideally several months to be sure that you have it right.

thatas odd

thats really odd then , whats the purpose of a sand bed then
Ive heard everysince that i started this hobby 4 years ago that the sand bed has microfuna and bactereia to break down nitrite and nitrates ect.
Every surface in an aquarium gets covered with bacteria and helps filtration, if it is exposed to moving water with oxygen the bacteria will be aerobic and the species of bacteria will break down ammonia to nitrite and then nitrite into nitrate.

If however, a deep sand bed has been used in a reef tank then the deeper layers of the sand 3-4" will become anaerobic, without oxygen, and the bacteria that lives there will use the oxygen molecule from nitrate and release whats left as harmless nitrogen. Therefor getting rid of nitrates...

Thats the plan anyway. Most of you will know already that i am against deep sand beds as crusts can form and one day when it breaks it will be like a bomb going off and all the nasty hydrogen sulphide etc that has built up over time will explode into your tank in one go! Killing everything.

Andy, you are totally right in what you said, it will only be the top layer of gravel that is aerobic and everything underneath becomes anaerobic. even with an Under gravel filter in there; it will soon clog up and they really are rubbish filters.

To prevent large areas of stagnated gravel and anaerobic conditions i always reccomend that people use only enough sand as to cover the bottom of a cephalopod tank and no more!!! A DSB may work for a year or two in a reef tank but NOT with a cephalopod. Their digging and sheer volume of produced waste would render them useless unless the DSB was in a sump as part of a refugium where the octo couldnt go.

So, to recap, a sand substrate does grow bacteria to an extent but not enough to filter a ceph tank (but can do a reef)

Live sand to me, in a caph tank; means that it has aerobic conditions on the surface and is crawling with amphipods and bristleworms to help break down waste.

Cephs need big protein skimmers, big filters and big water changes to stay on top of their tank parameters

You don't actually need to use any damsels to cycle the tank. This may also be the reason you lost one to begin with. Cycling a tank with fish is just as cruel as having one die due to the cycle as it places a great amount of stress on everything in the tank due to ammonia poisoning.

A better alternative that is just as fast and easy without killing or severely sickening any livestock is by using pure bottled ammonia without any additives. Results are comparable to any other method used and even more favourable than using livestock as you no longer have to worry about a fish contracting a disease due to ammonia poisoning then spreading it to any new additions to the tank.
In a nut shell to answer is,
1 month for the bacteria to colonize
3 months to mature
1 year until it looks good

(at least that's what I have seen in my tanks)
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