too much filter?
- Thread starter bingoboy
- Start date
Actually, a better way to judge over-filtration is by looking at the "gallons per hour" (or gph) rating for the filter. This is how many gallons are turned over by the filter in one hour.
There are mixed opinions, but I try to use "10-times" rule....for lack of a better rule name. You have a 30g tank, so that would mean your filter should be rated at or around 300 gph. Of course, the gph should depend of the fish you have. For example, slow current fish vs. fast current fish.
What filter do you have currently?
There are mixed opinions, but I try to use "10-times" rule....for lack of a better rule name. You have a 30g tank, so that would mean your filter should be rated at or around 300 gph. Of course, the gph should depend of the fish you have. For example, slow current fish vs. fast current fish.
What filter do you have currently?
The thoery is that you cannot over filter a tank - eg more is always better.
The practice can be difficult sometimes. Increased flow back into the tank can create unwanted disturbance and noise (if you use a spray bar), some fish prefer the quiet life. Another problem can be that if the fiter flow is too strong through the media, then particles that would normaly get trapped can be blown back out into the tank ad-infinitum.
So it may be good to over filter by maybe 30% - but not so good to overfilter by 300% (for instance).
The practice can be difficult sometimes. Increased flow back into the tank can create unwanted disturbance and noise (if you use a spray bar), some fish prefer the quiet life. Another problem can be that if the fiter flow is too strong through the media, then particles that would normaly get trapped can be blown back out into the tank ad-infinitum.
So it may be good to over filter by maybe 30% - but not so good to overfilter by 300% (for instance).
i've got a millenium 2000 hang-on 160 (i think) gph that was given to me and had been used for quite some time by the previous owner and looks quite old and my imagination tells me it's starting to sputter. my tank is quite stocked with fishes that seem to be fine (small congo tetras and small clown loaches mostly), tank has been pretty much how it is now for several weeks with no problems really. anywho, i went and bought a millenium 3000 hang-on 280 gph and am actually running both of them at the same time right now, till i figure the 2000 is a goner or i decided to stick it on something else. i know it certainly sounds overkill to run that much filter on a 30, but i am wondering if there are adverse effects of this.
"filter flow is too strong through the media" I think that's a spurious point here, because that would come down to faulty filter design not the relationship between tank size and filter pump capacity which is the real issue.
It's important to note the difference on the filter spec between the pump capacity and the filtering capacity. The 10 times rule is rarely attained in the latter.
It's important to note the difference on the filter spec between the pump capacity and the filtering capacity. The 10 times rule is rarely attained in the latter.
You can only filter what's there. You cannot filter out nonexistant bacteria. You have to bear in mind that not all fish like 10 times an hour water movement. Discus owners are often enthralled of eheim eccos as compared to the amount of media they have, the water flow rate is low, thus big filtration, little movement.
There are people around who have astonishly efficient filtration systems on their tanks allowing them to some high stock rates. They have had problems when the filter packs, because the water movement also oxygenates the water. No filter, no oxygen, fish gasping or dead.
I believe stocking rates (1 inch per gallon or whatever) were designed around volume of dissolved oxygen for breathing, and not the ability of the system to deal with waste long term.
There are people around who have astonishly efficient filtration systems on their tanks allowing them to some high stock rates. They have had problems when the filter packs, because the water movement also oxygenates the water. No filter, no oxygen, fish gasping or dead.
I believe stocking rates (1 inch per gallon or whatever) were designed around volume of dissolved oxygen for breathing, and not the ability of the system to deal with waste long term.
I know that i am often amazed at what some people can accomplish in terms of fish capacity and quantity...I can only conclude that this is a result of an extremely good filtration system that runs execeptionally well. I have known a few individuals that have really pushed the envelope on what's possible re: quantity of fish per tank volume.
yeah - but I think Waynes point knocks that on the head - a simple failure on that one peice of kit and oh boy are you in trouble
stocking calculators ? - lol - oh yeah.......we can all compare our stock levels to those and when we get to page 12 of the thread someone will mention "cookie-cutter".....rather an 'unresolvable issue' in my opinion - after all, rules are there to be broken, and we break them regularly in this hobby
Taffy - I would agree that in an ideal design of filter, overflowing should not be an issue, but I'd like to see the bench test figures on some filters I could mention - some add on mods can also create problems unintentionally. I've also read that things like carbon eventually leach back contaminents (a likelyhood that would increase with flow rate) and also read that this will not happen. Too many variables to discount the effect entirely - so I still remain cautious on that point.
stocking calculators ? - lol - oh yeah.......we can all compare our stock levels to those and when we get to page 12 of the thread someone will mention "cookie-cutter".....rather an 'unresolvable issue' in my opinion - after all, rules are there to be broken, and we break them regularly in this hobby
Taffy - I would agree that in an ideal design of filter, overflowing should not be an issue, but I'd like to see the bench test figures on some filters I could mention - some add on mods can also create problems unintentionally. I've also read that things like carbon eventually leach back contaminents (a likelyhood that would increase with flow rate) and also read that this will not happen. Too many variables to discount the effect entirely - so I still remain cautious on that point.
The original question is about the relationship between tank size and filter spec. The consensus is that you cannot filter out what isn't there but "over-filtering" is actually less of a concern in itself than controlling the current that is produced. Good filters come with flow regulators, moving the water more slowly through the filter, ie increasing the contact time between pollutant and media, must be a good thing.
Purple - your additional issue is whether the filter's internal design and media can handle the maximum flow generated by its pump. Tank size is immaterial to this. I've also read that carbon will adsorb and adsorb like a sponge until saturated then dump out. I've no idea about the science behind this but I recall thinking it was credible so go along with it anyway.
Wayne's excellent point, and Purple concurs, is that "over-filtering" should not lull the fishkeeper into thinking he can overstock. Some stock calculators work on the basis of water surface area, ie the capacity for a given tank size to perform gas exchange, CO2 out oxygen in. As an example, a tank of 48Lx18Wx15H is able to handle more stock than a 48x15x18 even though the water tank capacity is identical.
Purple - your additional issue is whether the filter's internal design and media can handle the maximum flow generated by its pump. Tank size is immaterial to this. I've also read that carbon will adsorb and adsorb like a sponge until saturated then dump out. I've no idea about the science behind this but I recall thinking it was credible so go along with it anyway.
Wayne's excellent point, and Purple concurs, is that "over-filtering" should not lull the fishkeeper into thinking he can overstock. Some stock calculators work on the basis of water surface area, ie the capacity for a given tank size to perform gas exchange, CO2 out oxygen in. As an example, a tank of 48Lx18Wx15H is able to handle more stock than a 48x15x18 even though the water tank capacity is identical.
