HOB nitrate factory myth?

[stingeragent]

Ok, so I've recently thought of getting rid of my sump and just using a HOB filter. I of course know of the "they are nitrate factories" rhetoric. I saw a random post somewhere the other day and it got me thinking. The guy basically said, whatever your HOB filter pick's up was already in the water whether you had the HOB or not. Ergo, the simple fact of having one isn't going to make it a nitrate factory anymore than if the same crud was sitting on a rock in your tank. I never thought about it that way but it makes sense to me. Of course a protein skimmer takes it out of the water column, but by having a HOB it just collects it all into once place. True it may be a nitrate factory, but the crap it picked up would be a nitrate factory either way if it is tucked behind a rock somewhere. Being un-biased I've tried to think of an argument to this but honestly can't come up with anything. All things being the same, live rock, etc, in the absence of a protein skimmer and just using a HOB, the amount of gunk in the tank will be no different. Having the HOB simply means whatever it sucks out will be in the media. If you don'ot have a HOB , it will just be somewhere else in the tank. Live rock is irrelevant as it will process the same amount whether you have a hob filter or not. Any thoughts?

 

[shifty51008]

the thing with HOB filters and canister filters is people don't clean them enough, as long as you clean them regularly they are fine to use.

the same myth goes for bio balls, as long as the bio balls are completely submerged they act just like LR rubble, but if used as a wet dry filter where the balls aren't submerged then yes they will produce nitrates

 

[ericarenee]

the thing with HOB filters and canister filters is people do clean them enough, as long as you clean them regularly they are fine to use.

the same myth goes for bio balls, as long as the bio balls are completely submerged they act just like LR rubble, but if used as a wet dry filter where the balls aren't submerged then yes they will produce nitrates

1+//

But bio balls after very GOOD Mechanical filter pad changed daily can be Good.But seriously who is going to do that.. i have prob 30 gallons of Bio balls in a box in my basement un used ...:lolspin:

 

[stingeragent]

Ok, to a point that make's sense, but why would it matter if it was cleaned or not. Does detritus in a tank grouped together somehow grow more detritus that wasn't there in the first place? If you had a HOB filter and cleaned it once a month, and you also had a tank with no HOB filter (everthing else being the same, live rock,sand, etc), would the one with the HOB have more nitrates and if so how? Because the gunk is compounded into one spot as opposed to being dispersed through the tank? Not trying to start an argument, just trying to understand. Here is how I'm thinking of it. Let's pretend there is a sugar magnet. You take a bucket of a water and dump in 1 cup of sugar. You have sugar all over the bucket. You take a separate bucket and put in a sugar magnet. You also put in 1 cup of sugar. That bucket sucks all the sugar to the magnet. Either way you have a bucket with 1 cup of sugar. If this was a protein skimmer vs HOB I can see how the protein skimmer would win 100% because it is able to remove everything from the water into the collection cup and take it out of the equation. But with a HOB vs just a powerhead blowing onto liverock, I can't see a difference except the HOB give's you a place to clean out all the collected gunk.

 

[Sir JRAD]

Just clean it every now and then and you'll be straight

 

[Waters40]

They become nitrate factories because, when they aren't cleaned, the detritus sits in the filter medium. You are correct, the same "factories" would be created by the detritus sitting in the tank as well. Ideally you want it removed from the system though to avoid the nitrate build up.....cleaning the HOB filters accomplishes that.

 

[CStrickland]

It isn't the amount of gunk, it's the environment in which it is breaking down.

A piece of gunk will float for a while and then sink. Absent some nitrate factory it will land where the flow is not strong, like a sand bed or corner of a sump. Away from the current the nitrogen cycle can progress much further because the denitrifying bacteria can live right underneath the nitrifiers. So ammonia is produced, converted, and off-gassed right at the source.

If the funk is caught in a nitrogen factory, the oxygen inhibits anaerobic bacteria populating. You have a condition instead where the nitrates are released into the water column and must then reach a low flow area in the rock or sand. Being low-flow makes this extra step less likely. So you have higher nitrates.

That's how I remember it from googling a while back. Obvi an oversimplification of the bacteria processes, I'm not great with that stuff. But you get the idea of what people are talking about. I think folks noticed higher nitrates when everyone was using trickle filters that came over from fresh water (where nitrates don't matter) and traced it back to their balls and floss.

 

[Sk8r]

Basically, bacteria live in the rock and sandbed that break stuff down to nitrogen gas. The bacteria living in your filter may include some of those sorts of bacteria, but, but a filter doesn't have the surface area of, say, a tank's rock and sand, and it doesn't have the stability, being subject to cleanings and more-and-less cycles.

A good sandbed rock/sump situation doesn't let crud pile up. A filter has to, or it's letting everything through. You clean it out, lower its bacterial load, and the cycle repeats. A sandbed/rock setup never varies, and if you flattened out all its pores to a micro-thin sheet, it would extend much, much further than a similarly flattened sheet of the typical filter's pores and substance.

 

[stingeragent]

Ok. Make's sense now. I know the obvious (just clean the stupid thing), but I'm the type of person that want's to understand the reasoning behind it. My grandma told me a story once from when she was younger. Her mother cooked something, and went extremely out of her way to place it in a certain pan that made no sense. She didn't know why she did it, that's just the way she learned it from her mom so that's how she did it. Well eventually someone went and asked the great grandma why it has to go to a silly pan and the great grandma said it was because she ran out of regular pans. I probably didn't tell that perfect, but the moral is, sometime's people do stuff for generations just because that's how they have been taught or learned that it's done even though it may serve no purpose what so ever. For any of my fellow veteran's on here, you know if you ask why something is done in the military that seems pointless it's because thats how its always been done. Doesn't have to make sense, its just done that way.

 

[Captain smoke]

Before I went to a sump setup I used a Mainland Emperor 400 for a HOB filter. I did not use the bio-wheels but I did use filter floss and carbon and a HOB eshopps skimmer, with this setup I could not keep my nitrates less than 10-15. I changed my setup to a sump with Eshopps HOB overflow and a 20g sump and s-120 skimmer and my nitrates dropped within a month to unreadable measures.

 

[PirateLove]

How is the HOB filter different from most Eshopps sumps that have that large foam block in the middle chamber? Wouldn't that be a "nitrate factory?"

 

[laga77]

There is a HOB on my 29G QT. Has been set up over a year. I put a small layer of floss under the foam block which gets changed weekly, along with a 3-4 gallon water change. After seeing this thread, I decided to test for nitrates. The result: 15 mg/l with the Salifert test kit. There is always something in the tank.

 

[Shawn O]

If you change out the floss at twice per week you should be better than using the sponge in it. To add to what others have stated: if you leave the gunk in the floss, with water flowing through the gunk, it should allow all that nitrate to return to the water column quickly. Sort of like running water through a tea bag rather than just letting it sit in still water.

I've noticed that my skimmer pulls a little less gunk when I change out my floss twice weekly, rather than once weekly. This tells me that the floss is pulling it out well enough. Makes me think that if I left my HOB empty, the skimmer would pull more stuff daily.