Flowrate ...high or low?

[Ryan Red]

An exaggerated example:
The water speeding pass a chamber containing CR at 1000 l/hr, can remove 4 mg/l of ammonia.
When the velocity increases to 2000 l/hr, the chamber can remove 2 mg/l of ammonia.
To compensate for the losses, the water has to pass 2 chambers in order to remove 4 mg/l of ammonia.


let me try , the above mean
flow rate (1000 l/hr) + chamber remove ammonia.
1 + 1 4 mg/l
2 + 2 4 mg/l

double flow rate require double chamber to remove same amount ammonia.

[Ryan Red]

flow rate in two tank (main tank and sump).

Main tank => higher flow rate pump(not till stress the aro) require for push the poo poo and ammonia to sump.


sump = > maintain optimium flow rate for BB to grow and nitrifying ammonia to nitrite to nitrate. the question is how to maintain as time to time the 1st, 2nd , 3rd comp will clog or slow down the flows.....

by adding flow meter to monitor the flow rate in each comp? and regular sump maintenance once flow rate affected?

the objective is to reduce or remove ammonia and nitrite lvl in sump before back to main tank.

[davidw]

whoa...very heavy discussion .... my simple opinion: 4x turnover recommended based on the usual sump size used by hobbyist generally, if hobbyist can afford to have a bigger than ordinary sump (means higher costs ) its definitely better to opt for higher turnover rate (again higher costs for a stronger pump)..... I personally prefer higher turnover

Originally Posted by Ryan Red

An exaggerated example:
The water speeding pass a chamber containing CR at 1000 l/hr, can remove 4 mg/l of ammonia.
When the velocity increases to 2000 l/hr, the chamber can remove 2 mg/l of ammonia.
To compensate for the losses, the water has to pass 2 chambers in order to remove 4 mg/l of ammonia.


let me try , the above mean
flow rate (1000 l/hr) + chamber remove ammonia.
1 + 1 4 mg/l
2 + 2 4 mg/l

double flow rate require double chamber to remove same amount ammonia.

Yes.....as what I had mentioned, it is just an Exaggerated example for easier understanding.

[Koji™]

I'm not a very chim person but this is what I do and believe.

Heavy mechincal filtration (thick layer of wool) before hitting the biological filter media in filter system. Flowrate can be fast but one must remember that the wool may choke and water can't pass through them as good as they are new.

But if flowrate is high and filter wool is not doing the mechincal filtration well enough, dirt will start pushing through and they will all start to choke the media underneath. Fast flowrate work well if the surface of the mechincal filtration is huge. If small chances of clogging is higher.

Just the way I keeping my fishes.

[Ryan Red]

refer to Koji bro, 2nd comp should have wool ontop as well. as better flow rate evenly flows from 1st comp to 2nd comp.

[jebus]

Originally Posted by |JTBC|

Hi bro, I'm still not very clear can you elaborate to us.
So High/Low flow rate, big/small sump tank and more/less medias are good?
An understanding of concept is more important. Tks.

like humans need time to do work, bacteria also need time to do work.

too little time, the work is half done
too much time, does not mean more work is done.

Originally Posted by BarraCuda™

My opinion for sump turnover is ... "as fast as you can afford".

Here's my reasoning,

Bio media is not single pass filtration. E.g Reverse Osmosis. Where the water only have 1 chance of passing through the media.

Bacteria will have higher efficiency when in higher waste concentration assuming carbon is not the limiting factor.

Eg. Both 100mg/l and 10mg/l of NH3 is passing through the same media with same flowrate. In terms of percentage NH3 removal, the 100mg/l will have a much higher efficiency than 10mg/l.

sounds logical that we want to bring solid waste( solid== concentrated)
to biomedia to have higher waste difference.

but do note that with higher Flowrate, the breaking down of waste into finer( hence less concentration) is also faster, don't think that bacteria action on the waste will be faster than the mechanical breakdown of waste. in the long run, the investment in higher flowrates might not yield better results

[Koji™]

Originally Posted by Ryan Red

refer to Koji bro, 2nd comp should have wool ontop as well. as better flow rate evenly flows from 1st comp to 2nd comp.

But if the first compartment is well stock with filtration wool, the 2nd compartment can be well stock with media rather than adding more filter wool.

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!

[davidw]

well said....the key is "not to submerge the wool..."..... I find this practice to be most useful...it really does wonders..