# Opinions on Pros & Cons of HOB filters in planted tanks?



## DaveK (Jul 10, 2010)

I'd say your analysis is generally correct. As I see it, as long as you don't put something that is rated for a tank many times the size you have, I don't see any issues. 

In addition, you can usually diap back the flow one way or another, and if the HOB filter isn't working out at all, it's easy enough to remove and you don't usually have a lot of money sunk into it.

I'd say give it a try.


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## gSTiTcH (Feb 21, 2013)

Hardstuff said:


> Ok this could be a repeat thread but I tried the search & could not find any. From my experience I know that HOB filters will outgas a fair amount of CO2 from Planted tanks. I have read this & personally observed this using calibrated ph meters & regency test kits. To me that is a con.


Depends on how low the water line is.


> However I also know that having a gas exchange of some kind at the surface is beneficial as well, meaning more O2 being brought into the aquarium. That is a pro!


Plants also add oxygen to the water. In a planted tank, I don't believe surface agitation is needed.


> I also know that HOB filters tend to scum up the surface know matter what you do but this can be minimized. That is a con!


Not true. HOB filters actually break up the protein and bio-films through surface agitation.


> Another Con can be additional flow agitation on the surface can cut down on par reaching lower levels of the tank. That my friend is a con!


I can't comment on this, as I haven't done any measurements. I can see refraction causing issues.


> They do offer good organic filtration but semi poor bio filtration. This would seem to be a tossup.


Organic filtration? I know of three classes of filtration used in the aquarium hobby:
-Chemical (Carbon, Purigen)
-Mechanical (Removes crud from the water)
-Biological (Converts Ammonia to Nitrate)

I have always had good bio-filtration with my HOBs. It is a function of the quality of the filter and the exposed surface area of the media.



> I run pressurized CO2 in 1 tank & DIY in another & from what I can see is that in the DIY tank the tank seemed to do better when the little Eihiem 2211 was backed up with the HOB filter. But the penalty was maybe losing a day or 2 in the fermentation bottle from the extra out gassing of CO2.


The yeast in the bottle will produce regardless of the CO2 concentration in the water. They don't shut down at 30ppm. Thusly, whether you had an HOB, no HOB, or if the CO2 line came disconnected, the amount of time the bottle was producing gas would not change.



> I have a low flow problem in my pressurized tank that I feel the HOB filter would help but I might have to crank up the CO2 a lot to help counter the CO2 discharge from the HOB filter! Some may say just point the spray bar up but that I find causes a lower flow problem down low.


So go get a re-circulation pump. Looks like an underwater fan. A HOB filter will only create flow in the area directly in front of it.



> Abstract: What is everyones opinion on using HOB filters in high or low tech applications? Thanks.


I use an HOB by my canister inlet. It is the filter that runs my surface skimmer (another great way to deal with surface scum).


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## exv152 (Jun 8, 2009)

Personally I don't use many HOB filters because they're an eye sore. Too much equipment is a con for me. If you raise the water level to be directly under the output of the HOB, you'll get optimal surface agitation, and avoid large off gassing of co2. Just avoid huge splashing. I have a HOB on my low tech nano/shrimp tank, and love it.


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## bsantucci (Sep 30, 2013)

Look at the Koralia Nano 240 for additional circulation. Great little pump and works great in my 46 gallon.


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## freak (Oct 15, 2013)

exv152 is correct about the level of the water and HOB's. I have 2 Penguin 350's on my 55g low light planted and if I keep the tank filled right up to the bottom of the HOB the surface aggitation is minimal.


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## milesm (Apr 4, 2006)

check out this link: http://www.prirodni-akvarium.cz/en/i...hp?id=en_co2ph. upshot is to increase co2 AND surface turbulence.


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## Hardstuff (Oct 13, 2012)

Thanks for all comments. As far as HOB filters not outgassing or playing around with high water levels is simply not true. Even with high water levels & reducing flow to lowest settings I was able to see CO2 declines with a digital ph meter. gstitch did not mention if he or she was using digital ph meters to back their comments up on CO2 not outgassing using HOB filters. Now The filter actually helps control excessive CO2 buildup with DIY CO2 however one can just time out the device if using an internal reactor.
I personally have tested HOB filters & I know they out gas a fair amount of CO2, however they do offer good gas exchange & some added flow + additional filtration as added benefits. 
As far as surface scum: from my experience they always do especially when turning them off & on again unless they have just been cleaned very well at that point. Once again I know some people will chime in & say they do not but mine always have in the past & will continue to.
Regarding busting up the protein & reducing some surface scum they do that but that does not mean they do not add some back as well at the same time! 
Some of the non out gassing comments seemed were geared towards low tech tanks & non CO2 injection systems. The HOB filters may actually bring some CO2 back into the CO2 starved low tech tanks & create balance benefitting the system. 
Some surface agitation Low Tech or High Tech has benefits in my opinion. It should help add healthy redox to the aquarium as long as its mild. What's mild? Opinions will vary!
I agree also about extra clutter in the tank. That was another con as well for me. But from a mechanical standpoint I was considering adding it to my High Tech setup since it is a small tank but is suffering from low flow low tank turn over right now.
Most circulators that I have researched have too much flow for such a small tank. In my tank the sections with the highest flow rates would grow BBA! Since I pulled my big filter out a Fluval 106 known for having high flow rates , my BBA has diminished + my small tetras do not hide as much now an actually school more even in this small tank! If I could find a real low flow circulator that would be perfect maybe 100 gallons an hour or less. High flow areas seem to grow more BBA at least in my tanks.
Regarding HOB filters not causing an early end to the yeast bottle. They do & I have verified this as well. I cannot explain this but my DIY set up holds CO2 well the way I cycle it. It seems to holds better in part because the reactor is better at diffusion than the atomizer. The DIY tank takes longer to build up CO2 than the pressurized but holds it better & stays more stable even when shutting it off for most of the night. Yes the yeast will only produce x amount of gas over time but the system holds the gas better. 
Thanks again all, I appreciate the comments


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## exv152 (Jun 8, 2009)

A HOB with the water line just below the output, where it creates a gentle ripple on the surface, is no different than aiming your canister spray bar at the surface for some agitation. Both methods will off gas co2. So I agree there. 

But, a HOB should not be your first option for increasing flow. They do a poor job of creating flow other than just in from of it, as someone mentioned earlier. There are several options for power-heads under 100 gph. 



Hardstuff said:


> …The DIY tank takes longer to build up CO2 than the pressurized but holds it better & stays more stable even when shutting it off for most of the night. Yes the yeast will only produce x amount of gas over time but the system holds the gas better.


I’m not sure what you mean when you say diy holds the gas better and is more stable than pressurized. But I, and I’m sure many others, would disagree with this statement.


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## Hardstuff (Oct 13, 2012)

What I believe is going on why I say my DIY holds gas better is because how it is delivered. My atomizer makes millions of micro bubbles. They float around the tank & some make it to the surface & a portion of those bubbles will escape into the atmosphere, hence CO2 discharge to a lower degree.
On the other hand my DIY system runs on an internal reactor powered with a powerhead with an additional ventura to dissolve the CO2 even more. Nearly 100% of the CO2 is dissolved . You can see the gas dissolve before your eyes so the tank in my opinion is more enriched. 
On the other hand since I loose time on changing the reactor & waiting for it to build up the gas , It takes longer in that way to bring the tank down ph wise. Contrary to the pressurized system when I am low with CO2 like early in the morning well before lights on I have gas on demand so I can push the tank down faster in that regard.
Now if I did not use an atomizer & opted instead for the internal reactor with this tank I would get better diffusion of CO2, but the trade would be more clutter in the tank. Hope that clarifies what I was talking about.
I just added the HOB filter set to my DIY set up not the tank in question to lowest FR but I will have to probably double the reactor cycle to help balance the tank. I feel in this case its the way to go because a circulating pump/ powerhead even under 100 gallons probably will not filter as well as the small HOB filter because of additional bio media & sponges. 
The tank already looks better with the surface agitation , the tank appears to have more energy now but its way too early to pass judgment.
I do agree with other comments about outgassing being similar as with canisters but that varies with outflow level as well. HOB filters are an is what it is filter in that respect. If this tank appears to react better I will go ahead & add a HOB filter to the pressurized set up.
I also feel that if HOB filters are used in larger tanks that DIY becomes impractical because of the out gas from them. Pressurized external or internal reactors should work well to help balance outgas but there are probably many folks saying big canisters should be used & sumps & I would agree with that as well.


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## sleepswithdafishez (May 23, 2013)

I have an Eheim Liberty 2040 on my 10g long.Besides the 2 sponge cartridges ,I also stuffed a sponge wrapped in filter wool in the compartment of the water intake ,a bit higher than the propeller ,of course ,and a bit of wool also between the 2 sponge cartridges.Also added a coarse piece of sponge in the squared shaped cascade outflow.
Now I can run it at higher rates ,without it agitating the surface too much ,cause before that ,cranking up the flow caused tsunamis in the tank.

I don't know if it is a good idea ,some people say you shouldn't stuff too much media in your filter.The water level inside has raised a bit since I increased the flow ,But it doesn't go above the 2 sponge cartridges ,which also rest on half inch of cotton wool I put on the bottom of the outflow compartment.So ,in general ,the water level in the filter has raised ,but still flows through filter media ,and the water circulates faster ,without blowing waves in the tank.

As for CO2 outgassing ,I think you are right ,a couple of weeks after starting the tank ,I began to see some white calcium-like deposits on some Anubias and Crypt leaves.They use carbonate in the water as a replacement for CO2 ,I was said it is because they live in harder waters and have that ability.I haven't seen any other of my plants do that ,still ,most of them are showing some yellowing ,so I started to dose some Iron + micronutrients product ,but progress is slow.

Thank you for this thread ,now I am even more convinced that I lack CO2.My PH is now at 8 ,and it used to be around 7.6 ,when I added the first plants.The more I added plants ,the more it climbed(I admit only measuring it when lights were on) ,but I'm pretty much sure CO2 outgassed from the filter and plants absorbing the rest is the cause.


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## Hardstuff (Oct 13, 2012)

Thanks sleepswithdafishez, that is a really good idea to try & slow down or minimize the flow on the surface. I have tried similar ways but I always found the water wants to back flow into the intake compartment & back into the aquarium in reverse, but only about 10%. But you took it to a new level. Especially with plugging the intake & using sponges at the outflow. 
Last night I tried installing my Fluval 30 again & that lasted a whole 6 hours before I noticed my ph rise from a nice 6.6 to 6.8 I knew it was over for that filter. Although after reading what you just posted I feel like giving the old plug try a go. 
For now I installed my only other last option which was a Fluval 1 internal. Within hours it helped my struggling Ehiem 2211 clear the tank much better! Best of all my ph fell back down to 6.6 which is my target range. So its obvious that HOB filters will out gas a lot. Thats with it turned all the way down & high water to the point of almost touching my canopy!
There probably is a way & similar to what you did to minimize the surface agitation, I would not give up on them totally until the tweaking is 100% tried! From a low tech stand, I can see them work well.
I forgot if you mention if you inject CO2 sleepswithdafishez . You still need to get your ferts+ lighting to name just a few in order & all else thats involved with this kind of set up as far as your yellowing is concerned. I have found that planted tanks are sensitive to just small changes, which can tilt your tank into an ugly mess. There are many factors that make these tanks run well and countless ways to mess a tank up!


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## gSTiTcH (Feb 21, 2013)

I didn't say HOBs don't cause off-gassing. That would contradict my statement about the gas exchange. What I said was the gas exchange in the water will not affect how long your DIY CO2 produces, which is what you seemed to indicate as your measuring device in the original post:



> But the penalty was maybe losing a day or 2 in the fermentation bottle from the extra out gassing of CO2.


Regarding the discharge of particulate at start up, unless your filter is continually dumping stuff in the return stream, that's pretty normal. Mine does the same thing, but it's quickly sucked back up with no problem.

Your atomizer is definitely wasting CO2 if bubbles reach the surface. It's why a lot of us use closed reactors (Cerges or Griggs) to dissolve the CO2. I would say DIY is ineffective in larger tanks because of the surface area for gas exchange. Surely any surface agitation would complicate the issue. A Griggs reactor with DIY might help.


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## Dany08fa (Jul 3, 2012)

heres my pros and cons on HOBs from my experience. my pros and cons are more of compairing HOB to canisters. i skipped pros and cons that all filters have. like i don't consider surface agitation really a pro because you can create surface agitation with just about any filter. i would only put a HOB on a tank 20gal or smaller.

pros:
-affordable
-easy maintenance
-you can plant HOBs
-it works!!

cons:
-lacking in bio filtration
-ugly
-inline is not an option
-harder to adjust flow rate
-cant do spraybar (i think)

if you have the money canisters are the way to go! the only HOBs i own and recomend is aquaclear or fluval, theyre pretty much the same thing though


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## exv152 (Jun 8, 2009)

Dany08fa said:


> ...if you have the money canisters are the way to go! the only HOBs i own and recomend is *aquaclear or fluval*, theyre pretty much the same thing though


They are both made by Hagen.


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## Hardstuff (Oct 13, 2012)

I do appreciate your comments gstitch an I do agree that DIY will only produce for a given time & that you did not say that HOB filters do not cause out gassing. However HOB filters do effect how long you can run a given fermentation batch BECAUSE the HOB filters out gas so much that during the production hight lets say you get 4 or 5 really good days, during those days the HOB filter will not effect CO2 discharge as much & may even help in CO2 gas control so the ph does not get pushed down too far.
After that things change fast as the production falls just a little your ph will rise & bounce a little. I consider this period non productive & I do not count those days. 
My DIY reactor hold gas really well & to a great degree because of low surface agitation, but I feel the ph would rise a little faster if micro bubbles were used.
That being said I babysit my reactor by using a timer which I change all the time considering what my ph is doing. I also use a heater in a bucket that seems to wake up the yeast more & produce better. The heater shuts off at night to cool down the bucket & seems to calm down the yeast which in theory gives me a longer burn time if they are less active during this time. In theory this should save me some gas, however you want to look at it. This is mostly a winter thing & may not work as well in the summer for some folks. 
I am now approaching day 10 & my tank is still 6.6! Some folks may chime in & say they can get 2 weeks or more but I would ask you what is your ph? + kh I feel 10-14 days will be the cut off point any further past that & the reactors will not be able to produce 30ppms of CO2 or more! Hope that helped to clarify a little what I was saying?


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## gSTiTcH (Feb 21, 2013)

I have never heard of someone investing that much time and effort into regulating DIY. That's kinda cool. At this point, I would consider running your reactor on a pH controller to maintain a steady pH.

Heat will definitely impact the rate of fermentation up to a certain point. I used to keep my bottle on a reptile under-tank heater to maximize the production I got from my bottles.

pH in my tank at rest is 8.4. I set the controller to run at 7.4. I haven't tested kh in a while as I just have simple fish and gave up on shrimping in that tank. Last time I tried to test, I stopped counting at 18 drops with the API kit. (Hooray Florida liquid rock)

All this said, with the HOB filter and DIY, you might see a problem. I got away with dual HOBs plus a canister on my 55g tank using 2-2L bottles into a Rex Griggs reactor. I didn't measure pH much with that set up, but the drop checker at 4dKh stayed nice and light green. I switched to pressure because I got tired of fighting with that much mixing. I also alternated the bottles to keep things steady. Changed out one bottle each week.


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## exv152 (Jun 8, 2009)

IME I noticed fermentation being affected by;

i) temperature, 
ii) type of yeast (I found more success with champagne yeast), 
iii) and the amount of sugar added, 
iv) and whether or not you put baking soda didn't really seem to change the longevity of the brew for me.

That said, this is an old method of DIY co2 since the introduction of the new citric acid and baking soda method. Apparently it lasts much longer, up to 4 weeks, as opposed to 1~2 weeks with yeast. But I think I'll happily stick with my pressurized systems & canister filters.


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## talontsiawd (Oct 19, 2008)

My opinion...

The only _real_downside of a HOB in a planted tank is having to maintain consistent water level. A second would be they can be ugly when on long tanks where they work best on the sides. That is debatable and plenty of tanks look fine with HOB. Lastly, they tend to be noisier than canisters. Again, debatable but you can't put a HOB in a cabinet which will quiet down a loud filter.

The plus for me is more oxygen. 


Off gassing CO2 doesn't matter. Just add more CO2. In my experience, I can use almost 2x as much CO2 in a tank with a HOB compared to a canister. So what...I think refilling a CO2 tank is a cheaper part of the hobby.

As for bio media. No scientist but it makes sense a canister does a better job. However, I really don't believe that you cannot stock a tank to a reasonable level with a HOB. So if you can stock your tank and it stays stable, it really doesn't matter what does a better job on paper, they both work well in practice.


That said, I am not a fan of HOB. I don't like to top off everyday and that leads to CO2 inconstancy. More importantly, if you have a bunch of stems, they get pushed around with just a slight drop in water level.

At the end of the day, I feel the differences in practice, not theory, are minimal.


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## sleepswithdafishez (May 23, 2013)

Hardstuff said:


> Thanks sleepswithdafishez, that is a really good idea to try & slow down or minimize the flow on the surface. I have tried similar ways but I always found the water wants to back flow into the intake compartment & back into the aquarium in reverse, but only about 10%. But you took it to a new level. Especially with plugging the intake & using sponges at the outflow.
> Last night I tried installing my Fluval 30 again & that lasted a whole 6 hours before I noticed my ph rise from a nice 6.6 to 6.8 I knew it was over for that filter. Although after reading what you just posted I feel like giving the old plug try a go.
> For now I installed my only other last option which was a Fluval 1 internal. Within hours it helped my struggling Ehiem 2211 clear the tank much better! Best of all my ph fell back down to 6.6 which is my target range. So its obvious that HOB filters will out gas a lot. Thats with it turned all the way down & high water to the point of almost touching my canopy!
> There probably is a way & similar to what you did to minimize the surface agitation, I would not give up on them totally until the tweaking is 100% tried! From a low tech stand, I can see them work well.
> I forgot if you mention if you inject CO2 sleepswithdafishez . You still need to get your ferts+ lighting to name just a few in order & all else thats involved with this kind of set up as far as your yellowing is concerned. I have found that planted tanks are sensitive to just small changes, which can tilt your tank into an ugly mess. There are many factors that make these tanks run well and countless ways to mess a tank up!


Yes I just started using DIY Co2.My PH has gone down to 7.6 ,just like when I started the tank ,after only 2 days.The Eheim HOB is on minimal flow ,water movement barely noticeable.if PH continues to drop ,I'll crank up the flow a bit.
Someone said temperature can affect production of ,CO2 ,generally = cold room ,means less bubbles.I am thinking I could insert my Diy CO2 canister in a bucket of water or something ,and add a heater with thermostat.Constant warm water so good bubbling from the canister.Hotter water - many more bubbles(maybe?)
For the moment I'll wait and see what gives ,and I'll try the warm water trick if not satisfied ,it's only been 2 days with CO2.


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## Hardstuff (Oct 13, 2012)

Thanks again gstich for your useful comments. I spend so much effort on my getto DIY CO2 tank because I want it to succeed. I want to learn how to beat bba algae. I grew the stuff when I switched over from total low tech, which is a common problem when switching over to a CO2 system. Plus I briefly switched lighting spectrums & intensified my lighting before adding CO2. That was more trouble. 
However since switching to a CO2 DIY driven internal reactor I have been beating this stuff back little by little. The tank is about 98% clean now! The only place the stuff currently grows is on the back glass in small patches. I caught the stuff festering on the powerhead only a week ago then nuked it with some peroxide & appears to be gone. 
As far as a controller , how would I do that with DIY CO2??? I use a solenoid like method now but it simply relies on turning off the powerhead. Plus right now I cannot afford to put any money into this tank. 
I think I already mentioned I gave up on the HOB filter . The ph went up too fast for me! No I am done with them unless as mentioned I was running pressurized then I would waist a little more gas & not care. 
Yes the extra O2 would be a plus but again in another tank with pressurized it may be ok but can still could be a problem in my opinion. Would not want to risk red algae!!!!!! Canisters can be flow adjusted which means you can dial in custom surface agitation for any tank provided you have the right filter.
Yes I agree on stocking levels as well, I have more faith in canisters than HOB filters as far as bio filtration anyway.
Bottom line: I feel that HOB filters can work if constant care is maintained regarding water line & flow if running pressurized but inferior to canister filters unless running very small tanks but then you run right back into CO2 issues. From a low tech standpoint they probably work well since CO2 is limiting & constantly low & stable anyway.


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## Hardstuff (Oct 13, 2012)

I forgot to mention that I am running R/o water on my tanks. I wish I did not have to because balancing this stuff is hard. My fish seem to like it but sometimes I feel besides CO2 deviations I am missing a nutrient or 2. That being said I do this because I have 21 degrees of hardness in my tap & 17 degrees of carbonates , ouch. I feel your pain gstitch. You think Florida water is hard , try AZ water it is as hard as it gets!


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## Terminalance (Oct 31, 2013)

> They do offer good organic filtration but semi poor bio filtration. This would seem to be a tossup.


The aquaclear offers great biological filtration. The fact that it is customizeable much the same way a canister is, makes it more economically efficient in my eyes. As with the majority of things in life, it comes down to what you can afford. 



> Personally I don't use many HOB filters because they're an eye sore. Too much equipment is a con for me.


How is a HOB too much equipment? If anything, it is far less equipment than a canister filter. A HOB sits neatly on the back of the tank, where a canister has all these hoses and spraybars and whatnot.


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## Brian_Cali77 (Mar 19, 2010)

talontsiawd said:


> My opinion...
> 
> The only _real_downside of a HOB in a planted tank is having to maintain consistent water level. A second would be they can be ugly when on long tanks where they work best on the sides. That is debatable and plenty of tanks look fine with HOB. Lastly, they tend to be noisier than canisters. Again, debatable but you can't put a HOB in a cabinet which will quiet down a loud filter.
> 
> ...


+1 

My "opinion" pretty much coincide here with talontsiawd . Although I like canisters + lilies much better, I have a couple tanks like this (my 60F as one), but HOB's when done right can look decent, be effective, and save money. I have a pair of brand new do!aqua pipes for my newly setup 60P that I can literally go buy another canister tomorrow and set it up that way.. HOWEVER, I choose not to (yet) because I wanted to go a different route for kicks and it's working out surprisingly well for me. I'm using a Fluval C2 with double the bio (replaced the carbon with bio) alongside a SunSun 301 surface skimmer HOB to not only keep the surface crystal (which it is) but I also filled that with extra bio. Also, although I don't monitor my pH and co2 with high tech meters or what not, my drop checker remains a happy green with about 2 BPS. If I do get some gas off, who cares... My plants are thriving, minimal algae... HC and UG carpeting in nicely. No fancy reactors either, just a cheap ceramic diffuser. 

I keep my water level high... I top off with my daily fert dosing. Just part of my routine, no biggie.

Skim through the progress of my thread. HOB doesn't look too bad IMO against a black background on my 60P.

http://www.plantedtank.net/forums/showthread.php?t=441873


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## Hardstuff (Oct 13, 2012)

Brian your tank looks very nice! However, I do not want to be a kill joy but your tank is very young yet. New tanks usually experience some early algae issues that can blow over & end up not being bad. That being said my tank went through a lot of early algae issues in the early stages. BGA, diatoms, green algae, & GSA! After I knocked then down 1 by 1 I was very pleased & for about 6 months I could do nothing wrong. Then in May I noticed BBA algae appear & my dream of an algae free tank WAS OVER. 
For the last 5 months I have tried everything I will not list because it would be another thread starter. 
It came from overconfidence & neglect. I Now have to work at it extra hard to avoid CO2 fluctuations! Watch out for those fluctuations from the HOB filters they could cause BBA at some point! My fluctuations did not come from HOB filters in my tank since I was not running them, they came from neglect!.


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## Brian_Cali77 (Mar 19, 2010)

Thanks... time will tell. I did have some nasty filamentous diatoms or rhizo... I already killed that off. I do get a bit of GDA, I just scrub off what my Otos aren't getting to by the time I do my weekly maintenance. No signs of BBA, yet... I do add some Glut to my daily PPS-Pro regimen. So that may give me a cushion to would-be algae problems. Also I think because I keep my water level high, there's less surface agitation (= reduced gas off). If I were just running the C2 by itself, I know I'd get a nasty protein layer where I'd have to run the HOB with a lower water level to create more surface turbulence to break up the surface scum (= more gas off). That's the beauty of running the SunSun 301 in tandem with the C2. Excellent tag team efficiency. If I run into problems, I'll be sure to report back. But I'm optimistic at this point.


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## exv152 (Jun 8, 2009)

Terminalance said:


> How is a HOB too much equipment? If anything, it is far less equipment than a canister filter. A HOB sits neatly on the back of the tank, where a canister has all these hoses and spraybars and whatnot.


It's too much equipment for me on a rimless tank. With a canister, using clear hosing & glass lily pipes (not a sparybar) it's obviously less equipment to look at. However, Brian Cali77 has done a nice job with his HOBs on his 60P, and the black background. Very nice!


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## Toby_kourtney (Jun 29, 2013)

I find in my 75 since I put my hob filter on it help regulate co2. Before my co2 would keep getting higher and by the end of the day it would slowly creep up to 50+ ppm. Now it hits lime green on the drop checker and stays there. I think you need a certain amount of surface agitation to make an equilibrium and my hob filter works perfect for it. I use a filter baffle so water level doesn't matter to an extent.


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## Hardstuff (Oct 13, 2012)

I feel you have more options with the kind of surface agitation that you can get with canisters. Keeping the outflow pipe well below the surface & using the flow control you can get any amount of surface agitation you need. Of course this is without the spray bar. 
With my Fluval I turn up a little more agitation during the night & decrease it a little during the day when CO2 is needed more. What I like is there is zero braking of any kind but I can get 60-80% of the entire surface moving to almost mimic a light windy day if the outflow is adjusted correctly. The flow control also doubles in respect that it creates more flow evenly around the entire tank, something that HOB filters cannot do in larger tanks, especially in getting a smooth even agitation around most of the surface & around the tank volume.


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## Hardstuff (Oct 13, 2012)

I forgot to mention that those drop checkers are really not that accurate. Especially if you are making micro bubbles. The tiny bubbles get lodged inside the drop checker & give you lower readings than you think you have. They are general guides only & can lag hours behind what the tank is in real time.
As far as your tank getting lower as the day goes & needing HOB filters to help off gas the excess CO2 , that would mean if you are running a canister that you need to adjust the canister so it moves the surface more but not braking it! 
I have miss adjusted my filter many times , you just have to be more diligent in your adjustments & play around with it some. 
I like running outflow pipes more than spray bars but sometimes both is better running 2 separate filters. 
I have used HOB filters as stated to out gas CO2 but found they waste a lot of gas. I know people will say the gas is cheap but a properly positioned Canister will beat any HOB filter from what I can see. What do I mean by beat? Better bio filtration , proper surface agitation , more bio media capacity, more flow options , better filtration & less bi pass, less surface scum, inline CO2 reactors, generally moves more water, out gasses less CO2 if properly positioned, less stuff hanging on the tank . The list is too long to list.


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## edstewart5 (Sep 24, 2013)

I just switched from a Fluval C4 HOB filter to a canister and I already like it better. Absolutely no noise I can hear (it's a bedroom tank), the flow is better throughout the tank and it looks less cluttered inside. Plus, the room for customization is nice!


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## Hardstuff (Oct 13, 2012)

Which one did you get? I like Ehiem , but Fluvals are good as well. I find the Fluvals have better flow. The down side to canisters are that they are harder to clean & a lot of folks put off cleaning them because they are more involved.


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## edstewart5 (Sep 24, 2013)

Hardstuff said:


> Which one did you get? I like Ehiem , but Fluvals are good as well. I find the Fluvals have better flow. The down side to canisters are that they are harder to clean & a lot of folks put off cleaning them because they are more involved.


I went the cheap way with the sunsun due to the UV sterilizer integrated with it also. Everything feels extremely sturdy besides the handles on the media baskets and the plastics for intake/output. 

Honestly, I think the canister will be easier than the HOB. I had to take the HOB off the back and take it apart piece by piece to clean it if it got really messy. The canister I just close the tubing, disconnect intake/output from filter and open it up.


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## Hardstuff (Oct 13, 2012)

I really feel any canister if cleaned properly will be much more involved than a HOB filter. Between the long tubing that needs to be cleaned with a long wire brush not to mention the head, & fittings should be cleaned along with the impella , media baskets sponges , there is just way more work & surface area to clean & be concerned about killing your beneficial bacteria. 
I would say it takes me 3-4 times longer to clean a canister. Especially trying to make the bacteria stay alive. I watch the temperature , & aeration while cleaning the filter which you would need to do with HOB filters anyway. 
The HOB filter would get the edge in ease of cleaning compared to canisters. But thats the least of the concerns to me .


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