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When looking at the filtration system, one must look at the whole picture and not just 1 subject of the picture. Let us examine the some of the popular topics:


Solid waste in the tank.

2 ways. Remove it manually or use a blower to push it to the filtration system. Though higher flowrate has an indirect effect in solving it but only partially.


Trap waste collected on mechanical filter.

3 ways of looking at it.

a. Clean the filter daily to prevent any solid waste from mineralisation. If the solid waste is remove physically, the ammonia will be much reduced.

b. Clean the filter frequently such as once a week. In biological point of view, a group of healthy and sufficient heterotrophic bacteria can break down the waste within a day. They can increase their numbers very quickly if the solid waste increases. In other words, cleaning the mechanical filter once a week is "better than not doing" at all. Does this means that we should forgo the mechanical filtration? No!!!

- Mechanical filter helps to prevent visible waste from clogging the bio-media.

- Heterotrophic bacteria excrete slime while minerialising the waste. If we allow the solid waste to breakdown at the bio-media, it will clog super fast.

c. Don't clean at all!!! If the population of heterotrophic bacteria is more than sufficient to breakdown the solid waste, it will attack the sludge too (DO must be high). If you look at a good bakki shower, you will hardly see any sludge or slime. I change my wool once in 3 months not because it choke with slime (in fact there are hardly any slime at all), it is due to habit. The trick is ......do not submerge the wool and must expose to fresh air.


Flowrate vs Rate of removal of ammonia

All medias are not equal. Some have more surface area than others. Some have smaller pores than others. Some are square, some are round ...etc.

In one setup, all the chambers are filled with jap matt only. In another setup, all the chambers are filled with CR. Since CR has more surface area than jap matt, it can be deduce that the setup with only CR has more bbs than the setup with only jap mat. This means that the setup CR can afford to have higher flowrate than jap mat. Reason .....due to the lesser bbs population in jap mat, it requires longer retention period to remove the same amount of ammonia as in CR.

Look at those fgt filter box for pond. For most setups, They contain mainly jap mats or similar products. If compare with those 3-5' sump for aro tank, the flowrate is much slower ....flowrate vs size ratio. Why? This is because the retention period has to be longer as the media used has lower surface area than those exotic bio-media commonly used in the sump. If you look closer at the jap mat, it contains lot of sludge/slime. If you look at those exotic media in our higher flowrate dump, you could hardly find them. Although this is not exactly a good example as most of the fgt do not use filter wool for the initial mechanical filtration, it is still close enough.

The end result, we are just turning the toxic waste to nitrate!!!

Water management for fishkeeping is a matter of "give and take". We have to prioritise on the Do's and Want.
Filtration system for fishkeeping is similar to mother's nature filtration system. Not 100% or even close but similar. We cannot mimic 100% due to cost, space constrain and man's "greediness plus selfness".


To be continue ...gone fishing!