I want to understand how HOB filter works.

Chiasmodon

I am planning to buy a HOB filter because my current filter (internal filter) is taking too much space.. im keeping a planted tank and once my plants grow too big the Internal filter will be blocked and clogged at the same time by plants and plant debris. What I don't understand about the HOB filter is the output of the filter "L/H" but here is what I think it means, (L) stands for a liter and (H) stands for an hour.. so in each hour, a specific volume is released by the filter like for example 180 liters/H .. so basically I think its the flow rate of the water coming out from the HOB filter.

here is my question, what flowrate/wattage do I need for 50 gallons?
 

carsonsgjs

A general rule, and one a lot of people go for, is to aim for a filter capable of filtering around 8-10 times your tanks water volume per hour. So you would be looking at something in the range of 400-500 gallons per hour.

That’s a very general rule though and it does depend on a number of things, including the stocking and bioload of the tank. It’s also important to know that the outputs claimed by filter manufacturers are usually much less in reality once media has been added in etc.
 

Chiasmodon

A general rule, and one a lot of people go for, is to aim for a filter capable of filtering around 8-10 times your tanks water volume per hour. So you would be looking at something in the range of 400-500 gallons per hour.

That’s a very general rule though and it does depend on a number of things, including the stocking and bioload of the tank. It’s also important to know that the outputs claimed by filter manufacturers are usually much less in reality once media has been added in etc.
Ty for this info. Are you familiar with internal top filters? I just want to know how can we reduce the water current coming from the outlet.
 

mattgirl

One other thing to mention. You can never have too much filtration so go for a more powerful filter than you think you need. Too much water movement is possible if it is affecting the fishes ability to swim or it is up rooting plants but you can never have too much filtration. If there is too much water movement the output can be baffled to disperse the flow.

carsonsgjs is absolutely right. The makers of these filters highly overrate their effectiveness. I actually run 2 penn-plax cascade 300's plus 2 sponge filters in my 55 gallon tank. The cascades are rated for up to a 100 gallon tank.

I will give you another example of never too much filtration. I am also running a cascade 300 on a 5.5 gallon tank. The little one I had on this tank quit on me. I looked to replace it but every smaller one I looked at had too many bad reviews. I had a new in box 300 so thought why not just use what I had. It is working perfectly.

If one internal filter is working for you one HOB should work but I believe in having backups so would run 2 filters on a tank this size. Having two means should one quit you will still have one running. Having two also means you just clean one at a time.

Here in the US it says GPH meaning gallons pulled through the filter each hour. In your case L/H means how many liters is pulled through each hour.
 

GlennO

Many years ago before I knew anything about recommended flow and turnover rates I would just look for a filter that was rated for my tank volume and then buy the next model up. Always seemed to work out well although these days I would be more likely to buy 2 of them. Don’t be afraid to oversize.
 

RayClem

I like having two filters in a tank so I can clean one of them without disturbing the other until the next maintenance cycle. I like using oversized filters.

I have a 55 gallon tank that uses an Aquaclear 125 (500 gph) plus a Aqueon 75 (400 gph). I use prefilter sponges on the intake tubes. That reduces the flow rate. It is also easier to clean the prefilter sponge than it is to tear down the filters for cleaning.

I have a 20 gallon tank that uses two Aqueon 50 filters (250 gph each). Although that sounds like the flow would be excessive, because one filter is at each end of the tank, it is not a problem. Once again, I use prefilter sponges on the intakes.

Also, if you get a HOB filter (or two) forget about the expensive filter cartridges that come with many of them. The cartridges come with a thin layer of filter material and some carbon. The filter material is not sufficiently thick and most tanks do not need the carbon. The manufactuers want to use the cartridges for a few weeks and then replace them. When you toss the old cartridge, much of the beneficial bacteria is lost. These cartridges are great moneymakers for the manufacturers and pet stores, but they are far from ideal for the aquarium. Take a look at some of the YouTube videos on how to modify the media in your HOB filter to make it much more fish friendly.
 

Similar Aquarium Threads

Replies
24
Views
3K
Tiny_Tanganyikans
Replies
5
Views
867
Fisheye
Replies
2
Views
253
rebellonik
Replies
8
Views
381
jdhef
Replies
3
Views
294
finnipper59

New Aquarium Filter Threads

Latest Aquarium Threads

Top Bottom