# Undergravel Filter..to be or not to be?



## goldgrille85 (Jan 17, 2012)

I have a 55 gallon tank that currently has a pleco(8"), tiger oscar(4"), electric blue jack dempsey(3"), purple parrot(2.5"), firemouth(2"), and two corry cats. FYI I just bought a 180 gallon setup last weekend that I will be moving the pleco, oscar, and parrot into. My wife and I are currently selling our house so I'm not gonna set up the 180 until after the move, so it may be a month or two before it's up and running. On my 55 I currently have an aqua clear 70 HOB, a Fluval 405, and an aqua clear 70 powerhead running an under gravel filter and I do a weekly 25%water change with a gravel vac. I have been building a DIY under gravel jet system that is almost complete. I just use basic aquarium gravel purchased at a LFS as my substrate. Before I install my UGJ system I am just curious bout a few things...I have read more than one discussion about under gravel filters and it seems many people on this forum are not fans of these filters. It actually seems as if some people feel they do more harm than good. I am seriously considering removing mine when I install the UGJ system but I am afraid this may create a mini cycle if I lose too much beneficial bacteria. I would think that with the HOB and the fluval both running they would hold enough beneficial bacteria to maintain safe water conditions but I want to be sure of this. So, is it a good idea to get rid of the under gravel filter and if I do would there be any advantage to switching to a pool sand substrate and getting rid of the gravel?


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## Hoosier Tank (May 8, 2007)

At the risk of being flamed by other members, I'll admit I have been using UGF's since they came out in the '70s, both with an air pump and with a power head. They are used with a HOB and work for me, plain and simple.
Now that being said, when you break down a tank or change to sand and remove the UGF plate you will find what may be the NASTIEST sludge known to aquatics... YUK!
I strongly recommend NOT doing this with your fish IN the tank. Since you are currently running the AC 70 and Fluval 405, and they have been running a while on the tank, I doubt you will have a cycling issue once the UGF removed. But you will need a place for your fish for a couple days.
Here is what I would do... Move those two filters, water, and some of the gravel from your 55 to another tank first then the fish. If you don't have another temporary tank, pick up a 29 or a 20 off Craiglist (cheap) or Freecycle (FREE). Sometimes you can even find 55 or 40L people just want to get rid of. You are only going to use it for a couple days tops but clean & rinse it well.
Then breakdown your 55 and install the UGJ system. If you go with sand be sure you have a pre-filter on your powerhead you are using for the UGJ. Once it settles (overnight or more) and you are happy with it, move the filters, water, and fish back to the pretty remodeled 55. Now, put the gravel from the temporary tank in a Ladies nylon stocking and lay it in the remodeled tank. After a week or so you can remove the nylon stocking with the gravel. 
You should be good to go after that and can either keep or re-sell the temporary tank.


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## goldgrille85 (Jan 17, 2012)

That sounds like a great plan. I was really unsure how to go about doing this safely so I really appreciate the advice, Hoosier. I just so happen to have a 29 gallon tank at home that I can use as a temp for a day or two if i do decide to remove the UGF. I will be using a mag pump for the UGJ'S and it does have a foam pre-filter so I think it should do fine.

My main goal here is "ease of maintenance" and I have read a lot of people find sand very easy to keep clean. I'm just curious if anyone has experience using both and which one is easier to maintain (I plan on adding the UGJ's either way).


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## PfunMo (Jul 30, 2009)

No reason to consider flaming anybody but I would like to throw in my thoughts against UGF. It is not that they don't do a good job and I do like the idea of low maintaince. My problem with them is over the long term, they have a way of failing in a way that doesn't show.

With other filters we can see the media getting clogged in HOB or see the water flow decrease in canisters. In UGF, I found they begin to get some of the small filter plate holes stopped up. As those stop up, more water goes through the remaining holes and no reduction in flow is noticed. The stoppage gradually spreads across the bottom of the plate, under the gravel all out of sight. As the water stops flowing in these ares, the O2 using, good bacteria is replaced by bad bacteria that does not use O2. These make the filter smell like a sewer because it is a sewer which does nothing for your fish. Depending on luck, one may find need to redo the tank and pull the plates to clean them before a critical level is reached. But then if your tank is stabil and you don't tear it all down to look, you will gradually lose your filtering until one day, your fish begin to suffer and you can't figure why.

To me, it is just too close to being a ticking time bomb waiting for some really awkward time to let you know your filter has stopped working! And then I never really liked cleaning sewers, either.

No flaming intended, just my view.


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## Hoosier Tank (May 8, 2007)

...and very well put, those are the issues with a UGF... so no offence taken. 
*goldgrille85*: You are obviously used to the Gravel Vac routine but vacuuming sand is really easy, there is a video on here somewhere (Library section). Only other change is to stir your sand once a month or so to keep the toxins from building up underneath.


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## PfunMo (Jul 30, 2009)

Glad to hear you say you are not mad!!

As I said, I really wish there was a way to make UGF that one could see and monitor better. The idea is nice and a filter that didn't need the constant cleaning and changing would be great. I've read about people who have their tanks set on stands and can look at the bottom but I've never been there.

I'm still looking for that "magic" better way!


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## goldgrille85 (Jan 17, 2012)

My tank is on a metal frame stand with a open bottom so I took the liberty to get some pictures to share with everyone. Hoosier, you are right, this is pretty nasty...



















It's hard to believe my water is crystal clear with all that sludge hanging out under the gravel. This is gonna be a dirty job. I'm calling Mike Rowe...


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## PfunMo (Jul 30, 2009)

Great job with the pictures. I don't want to seem to be piling on you but it is exactly what I found in my UGF. If your water is still good looking it is because the debris is still going down to clog more holes. I would be interested in any water quality tests you have done? Any records of how the nitrite and nitrates have been running. It was not at a time when I was testing but I think I would have been shocked at how bad my water had become. If we found a HOB filter with that much grung we would beat the guy silly for not changing or cleaning it.

Nothing personal against you. I just don't like UGF that sneak up on me!


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## Hoosier Tank (May 8, 2007)

Yep, that's the stuff I was talking about... I think it is better to think of these as "Septic Systems" rather than calling them "Filters". :roll:


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## goldgrille85 (Jan 17, 2012)

I don't take anything on here personal. I am open to all criticism. I am fairly new to this hobby so I am just trying to learn as much about everything as I can before I start up my 180 gallon. Just reading discussions on this forum has provided me with a ton of good information. I really appreciate all the input and feedback that everyone provides, good or bad, i just take it and try to learn from it, so no need to worry about offending me. I figure most of you know more about this stuff than I do.

My water tests are actually all pretty good. My nitrites stay at zero but it does seem as if my nitrate level rises a little quicker than what i would expect it to. I don't have my aquarium overstocked and I do not believe I overfeed. My water tests at 5 ppm (nitrates) straight out of the tap and about 24 hrs after a water change with a gravel vac my aquarium water usaully tests around the 10 ppm mark. I usaully do my water changes every 5-7 days and by that time my ppm are usually somewhere in the 30 's range pushing 40. Considering that I over filter my aquarium, it does seem a little odd to me that my nitrates reach a dangerous level so quickly. Maybe this is normal and I am wrong in my assumption, but since I am planning on removing the UGF as soon as my sand arrives, I will know soon if there is any noticable difference in how fast the nitrates rise!


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## PfunMo (Jul 30, 2009)

Good info there, thanks. I was just guessing that a lot of the gunk is still debris that is decaying. With other filters, we clean it off and get it out of the tank so that it doesn't add to the ammonia for the filters to handle. If it is collected by the filter but stays in the tank, it seems that it will add to the load the filter bacteria has to convert. As more and more collect, the load gets bigger and at the same time the area where there is good bacteria decreases as water stops flowing. That sets up a situation where the needed filtering and the available bacteria reach a crisis. I remember in my early fishkeeping things would be rocking along fine and then gradually I had more and more trouble. Fish would get funky and then get sick. All kinds of weird little things that I would try to treat with the best guess on what medicine would work. Without testing and knowledge about the nitrogen cycle, it was the best we could manage and we lost a bunch of fish. Changing carbon and filter floss combined with a really intense cleaning was considered the way to go.

Hindsight is wonderful for the future but little help with past mistakes.


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## DialedN07 (Feb 24, 2012)

First post here (but have been around for a month or so reading as much as I can)

I have a question about my planned tank setup.
I have a 150 and am also planning to establish my UGF. However, the tank that was given to me has 6 pre-drilled holes in the bottom from a friend who was using the tank for saltwater. I would like to take these holes and utilize a quick release for the water to drain into a 5 gallon bucket under the tank. This would account for approx 30 gallons to be released from the tank (from under the filter) which would dump a majority of this sludge right out of the bottom of the tank and I could then do the normal vacuum for the remainder of the water change.

Has anyone heard of using this method? In my inexperience and simple thought process, it seems like it would be the ideal solution to this sludge problem posted in the picture above.

(Sorry I really don't want to hi-jack this thread, but thought it could add some interesting conversation to it) opcorn:


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## prov356 (Sep 20, 2006)

> I have a question about my planned tank setup.
> I have a 150 and am also planning to establish my UGF. However, the tank that was given to me has 6 pre-drilled holes in the bottom from a friend who was using the tank for saltwater. I would like to take these holes and utilize a quick release for the water to drain into a 5 gallon bucket under the tank. This would account for approx 30 gallons to be released from the tank (from under the filter) which would dump a majority of this sludge right out of the bottom of the tank and I could then do the normal vacuum for the remainder of the water change.
> 
> Has anyone heard of using this method? In my inexperience and simple thought process, it seems like it would be the ideal solution to this sludge problem posted in the picture above.


Unlikely that anyone's done this before, but sounds like it would work really well. You can also convert these filters to reverse flow. I think part of the reason they're not used more by members is that most use sand for their cichlids.


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## PfunMo (Jul 30, 2009)

Sounds like a quick way to dump water but for me in that size tank it would be too many buckets! I will admit to trying to keep work to a minimum, though.  
Any chance of adding a drain instead of the buckets?

Second thought would be a concern whether the water would draw form all across the filter plates or just through the closest section so that much of the plate would not get cleaned. Water tends to take the path of least resistance and if it did not pull water from the far end, it might still become a problem. The thing that bothers me most about this type filter is the unknown part. You really can't tell whether the filter is drawing water through most of the filter plate or if most is stopped working and the water is all drawn through a small portion. When you do get around to moving the tank and pull the plates, will you find a clean operating filter or the stagnant sewer setting? Short of looking up from the bottom or pulling an entire section out to look, I find no way to tell if it is working.


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## DialedN07 (Feb 24, 2012)

PfunMo said:


> Any chance of adding a drain instead of the buckets?


The Real plan would be to have a two into one type of drain that would attach to a quick disconnect to a regular garden hose. This way, I would have three "drains" and one garden hose that would go right out my front door into my shrubs probably 5-10 ft away.

This is a horrible rendering of what my tank looks like now, but for 2 minutes in MSFT Paint, it gets the point across.

View from the top









From the front


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## goldgrille85 (Jan 17, 2012)

You could have all three drains come into a 4 way splitter then out you the bottom of the splitter into your garden hose. May be a little less maintenance yet. Just a thought. I do like where you are going with this though.


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## Hoosier Tank (May 8, 2007)

if I was setting up a pre-drilled 150, it would have a wet/dry sump... without a second thought.


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