[CARE] A water cycle

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For a Water Cycle (N cylce from http://www.fishlore.com) when we are doing the cycle of the tank, need to go through stage 1-3 (N cylce from http://www.fishlore.com)
(picture from http://www.fishlore.com)
1) NH3/ NH4 deadly to CRS.
2) NH4 (aerio bacteria) --> NO2, this process bacteria need O2 (air pump) and the bacteria can is ok to light.
3) NO2 (aerio bacteria)-> NO3 should be around the same process in step2, a filter and O2 (air pump) is good for this.

The last step 4 :

"Nitrates are not as harmful to tropical fish as ammonia or nitrites, but nitrate is still harmful in large amounts." (from http://www.fishlore.com)
and this is the most common problem for CRS breeders keeping NO3 below 25ppm
4) NO3-> back to tank / in air <--- this need anaerobic bacteria
(they prefer no light and no O2 to process )
"In saltwater fish tanks, live rock and deep sand beds can have anaerobic areas where denitrifying bacteria can breakdown nitrates into harmless nitrogen gas that escapes through the water surface of the aquarium. "(from http://www.fishlore.com)

Since my problem is high NO3 and the problem is from step 4,
I did the DIY, is strengthening Step 4 and providing larger environment for anaerobic bacteria thats why I use black tube and a long slow flow tube with running out of O2 (since the tube is at the end of the canister step2,3 the bacteria use it) and this is the reason I attach the tubing at the end of the canister.

Also, UGF can kind of turning the substract to a bacteria grow area. and i only use 2/3 area of the tank as UGF. left side without UGF mainly for plant and for grown anaerobic bacteria (susbtract lack of light). Right side is for aerobic bacteria grow. here is how and why I use UGF.

Then after running it 2-3weeks. before NO3 is 25-35ppm, the DIY did lower to Zero.

Thats about how its work,
if u have a same NO3 problem, here is my suggestion DIY that cost only the long black tubing for $15 from internet and a hole of the outflow.

but i didn't use it anymore, since my other pre fiter can do the same work.
from 20L thread
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