# Timer - HOB Filter



## desjardo (Aug 30, 2008)

I have a 50-75gal HOB filter on back of my 35gallon tank. Seems a little overkill. It is self priming so would it hurt to set a timer so it hsould off for 2 or 3 hours a day? Just curious.. Seems they are always swimming...


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## KnaveTO (May 13, 2007)

First off there is no such thing as overkill when it comes to filtering a tank. Secondly never turn off your filter system unless you are cleaning the tank or system it self.


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## Shattered (Feb 13, 2008)

To elaborate on what KnaveTO said; 

1. The more filtering the better, in simple terms you're leaving lots of room to grow in case for any reason the bio-load gets bigger. The bigger the filter the more it can clean over-time. But it does take time to build up the bacteria colony. 

2. The longer you shut off your filter, the worse it is for the bacteria colony. They will starve and start to die off. I read someplace that when the bacteria dies, they become toxic to your fish. 

I could be wrong on both counts, so I would recommend researching how the filter works, and about the bacteria. Sometimes it's a lot of dry reading, but at least you won't just have my opinion.


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## Cory_Dad (Apr 18, 2008)

Shattered said:


> To elaborate on what KnaveTO said;
> 
> 1. The more filtering the better, in simple terms you're leaving lots of room to grow in case for any reason the bio-load gets bigger. The bigger the filter the more it can clean over-time. But it does take time to build up the bacteria colony.
> 
> ...


You're not wrong but I think you can 'overfilter'. Along with turning off your filter and having your bacteria starve, if you have too much bacteria and not enough food (ammonia) for all of it, then won't it also starve?

But in desjardo's case, a 75 gallon filter for a 35 gallon tank is not over filtering, it's safety filtering. An Eheim 2217 in a 5 gallon IS over filtering; it's also called a dishwasher.


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## ameekplec. (May 1, 2008)

Cory_Dad said:


> An Eheim 2217 in a 5 gallon IS over filtering; it's also called a dishwasher.


Not if you don't use the spray bar!!! lol

Like everybody has said, there's pretty much no such thing as over filtering. All my tanks are 'overfiltered':

75g - 2x Eheim 2217 (Total rating, 318G)
20g - 1x Eheim 2215 (Total rating, 93g)
15g - 1x Eheim 2215 (Total rating, 93g)
10g - 1x Eheim 2213 (Total rating, 55g)

As you can see they are all 'overfiltered' per se, but I still think it could be better.

And also, turning off your filter for extended periods can cause the bacteria to all suffocate and die, causing a spike and mini-cycle, which are both undesirable.


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## Canadiancray (Apr 27, 2006)

There is no such thing as too much bacteria in a tank. It doesn't happen. The bacteria levels in your tank/filter are constantly changing, going up & down with avail. food. As such there is NO such thing as overfiltration No matter how big the filter is your biological filtration is only as good as the tank needs it to be.

However you CAN have too much water flow for the size of the tank. This really depends on the tank layout & the fish you are keeping.

Craig



Cory_Dad said:


> You're not wrong but I think you can 'overfilter'. Along with turning off your filter and having your bacteria starve, if you have too much bacteria and not enough food (ammonia) for all of it, then won't it also starve?
> 
> But in desjardo's case, a 75 gallon filter for a 35 gallon tank is not over filtering, it's safety filtering. An Eheim 2217 in a 5 gallon IS over filtering; it's also called a dishwasher.


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## Darkblade48 (Jan 28, 2008)

I agree with Canadiancray; the bacteria levels will change according to the available substrates they require for their metabolism. So if there is less ammonia, then there will be less bacterial growth (or possibly some die off, if you were to (say) go from 50 fish to 5 fish).

It's a common misconception that a tank can be overfiltered, but as Canadiancray also mentioned, it's usually a case of too much water flow/current that will result in unpleasantness for some fish.


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## Cory_Dad (Apr 18, 2008)

Canadiancray said:


> There is no such thing as too much bacteria in a tank. It doesn't happen. The bacteria levels in your tank/filter are constantly changing, going up & down with avail. food. As such there is NO such thing as overfiltration No matter how big the filter is your biological filtration is only as good as the tank needs it to be.
> 
> However you CAN have too much water flow for the size of the tank. This really depends on the tank layout & the fish you are keeping.
> 
> Craig


Thank you for the correction. The 'too much bacteria' wasn't what I meant to say in that context. I was thinking of the situation where you have a healthy bacteria community in a filter (doesn't matter the size) then your remove or lower the food source. In that case there is 'too much bacteria' for the available food supply and they will begin to die which is ok unless you then increase their food source by adding more fish. That's when you get a mini cycle. Did I say that right now?

I myself have an Rena XP4 on my 60, an Eheim 2213 on my 20 long and an Eheim 2215 + AC 50 on my 25, all considered 'over filtered'. I did it not because they filter 'better' than a the smaller models, but because they have more water flow and potential capacity. They also don't need to be cleaned as often.

The 'dishwasher' comment as well was a bit off. It's not a case of over filtering, it's a case of too much water flow albeit from a filter. It's also a case of having too much money. 

Again, that's for the correction and clarification.


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## Darkblade48 (Jan 28, 2008)

Cory_Dad said:


> I was thinking of the situation where you have a healthy bacteria community in a filter (doesn't matter the size) then your remove or lower the food source. In that case there is 'too much bacteria' for the available food supply and they will begin to die which is ok unless you then increase their food source by adding more fish. That's when you get a mini cycle. Did I say that right now?


Yes, this is correct. If the bacterial die off is sufficient, then you will get a mini-cycle.


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## Tanked (Sep 9, 2008)

I just turn my filter off for 15-20min in the morning, and 15-20min at night when feeding.. As my filter sucks up the food as soon as she hits the water.


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## sawman88 (Sep 29, 2008)

just to put my 2 cents in.. you cant over filter once the water is clean its clean . some fish like lots of current... some fish totally hate it. too much current can totally suck..


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