Undergravel Filtration?

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Undergravel Filtration?

Post by FunkyFredFrog »

Hi guys

I've currently got a community tank which leans heavily towards catfish - plecs / loaches and bottom feeders (ghost knife too).

I think I made an error choosing Coral Sand for the bottom but I thought I may get Elephant Nose Fish so plumped for this option.

I have a 1010 x 600 x 500 mm tank with an external filter but I did have a Fluval 2 internal filter AND a Stingray 15 inside as it needs heavy filtration - the amount of waste is unbelievable!

What I want to know is can I put undergravel filtration in with the coral sand? Its very fine.

I used to have black gravel in my old tank and still have it in the garage.

What would be better?

Constant gravel cleaning with a suction pump type cleaner?

UGF and Change gravel completely (I have no other tank setup so maybe a bit problematic)?

Cheers guys! :d :d
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Re: Undergravel Filtration?

Post by Loracidlover »

Hello.
Coral sand is indeed a poor choice for the fish you are keeping, mainly since it will raise the pH and hardness of the water quite significantly, really not ideal for any south American fish such as Loricariids. I suggest you change this as quickly as possible for something inert as far as water chemistry goes.

UG filtration is a little out of fashion now, and I think not without good reason. When I was younger people were a lot keener on it, but the massive build up of wastes over extended periods in the base of the tank tends to lead (in my experience) to almost uncontrollable nitrate rates unless very regularly vigorously cleaned. A bit of a "nitrate factory" as the reefkeepers say. You would be better off with powerful external filtration and regular cleaning of the substrate with a siphon, not too arduous if you take out a just a couple of buckets a week, in addition to the regular water changes.

What external filter are you currently using? and what are the water parameters in the tank?

Conrad.
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Re: Undergravel Filtration?

Post by FunkyFredFrog »

I did a PH test the other day and it went bright blue - at least 7.6 - my test only goes upto that level.

I have a Sera bioactive 250 external filter and a Fluval 2 internal filter.

What would be an "inert" substrate? My black gravel wouldn't be a problem to wash off and replace but I'm not sure how to go about replacing unless I put up my small tank until I'd got all the coral sand out.
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Re: Undergravel Filtration?

Post by FunkyFredFrog »

Also - how do fish places keep their tanks so clean? they seem to have undergravel filters exclusively.
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Re: Undergravel Filtration?

Post by MatsP »

The Fluval 2 (is that a Fluval 2, Fluval 2+, or Fluval U2 model - not that it makes a huge difference, as they are all small filters). The 2+ is meant for tanks up to 90 liter, the U2 for up to 110 liter.

The Stingray 15 is for a tank of 75 liter.

So with the best possible of these values, your 300 liter tank is underfiltered by about 120 liter - and in my experience, manufacturers are quite optimistic when it comes to specifying what size tank a certain filter is suitable for - I tend aim for a filter that is for a tank 1.5-2x the size of my actual tank, or use two filters for about the size of the tank.

Nice size & shape tank, by the way - should be a good tank for plecos and such.

I agree that calciferous gravel/sand (such as coral sand/gravel) is a bad idea in a tank for (most) South American fish. This type of sand will raise the pH to somewhere between 7.5 and 8 - which is acceptable for some South American fish, but not something you should strive for.

And undergravel filters are probably not the greatest idea for plecos anyways. The principle of pulling all the dirt into the surface on which the fish tends to spend most of its time seems to be a poor solution, in my mind.

I prefer a sand substrate, rather than gravel. There are lots of different products in the LFS, and DIY stores etc sell a number of different types of sand that can be used in aquariums as well. The most commonly used on is play-sand. You can also use silver-sand, kiln-dried paving sand, and if you know what to look for, several other kinds. All are around £5 for a 25kg bag. You probably don't need more than 25kg anyways.

Fish-shops clean their tanks frequently, and most of them don't feed their fish as much as I would do in my home. Also, they DO have tanks that are filtered appropriately for their inhabitant (at least most shops do). I know a few shops that still use UGF, but most shops these days have sump-filtration, where a large tank containing several kinds of media sit under the tank(s), and water is pumped from the sump to the tank, which has some sort of overflow connection back into the sump. This is sometimes also connected to a central filtration system. All Maidenhead Aquatics stores use this method of filtration, as do Aquajardin, Pier Aquatics, Barlows Aquatic Trading, BAS, Wholesale Tropical and Wildwoods - of the top of my head, I can think of two shops that don't: Aqualife in Preston and Dorking Aquatics.

The lack of use in shops is not an argument against undergravel filters as such, and shops that do use UGF are no less good than those shops that use a centralized filtration system - it's a question of work vs. cost. Anyone building a new shop today will use centralized filtration simply because it is more cost effective - it's easy to clean and costs are comparable.

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Re: Undergravel Filtration?

Post by Loracidlover »

Hello again,
Mats, you appear to have missed the external that OP is also using, when also considered, the tank has a fairly decent amount of filtration, so this shouldn't be too much of a problem, unless stocking is excessive.
I'd agree that a sand substrate would be best, considering the number of bottom feeder you have. Play sand, as mentioned, is good, or pool filter sand, which has a slightly heavier grain and is less likely to end up in the external (therefore reducing impeller damage). You can buy pool filter sand from swimming pool supply places. As far as replacing it goes, it's a bit of a job, but I've done it in 1 go with a 250 litre tank before, net the fish an either put them in a large tub/bucket or spare tank, then drain, rinse and replace the substrate.

The only thing I can recommend to stop waste build up is regular hoovering of the substrate with a good old siphon. I'm afraid copious waste is often a part of catfish husbandry. Electronic hoovers are also available, if a little pricey :http://www.charterhouse-aquatics.co.uk/ ... p-971.html

Conrad
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Re: Undergravel Filtration?

Post by MatsP »

I did indeed miss the external filter.

I have sand in all my tanks (different types in different tanks, depending on my mood and the type of fish kept in the tank). I do get sand in the filters, but for the three or so years I've used sand in my tanks, so far (touch wood) I've had no problem with sand in the impeller. I'm not saying it can't be a problem, but a correctly set up, good filter, shouldn't allow sand to enter the pump housing, as there should be several particle filters in between...

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Re: Undergravel Filtration?

Post by FunkyFredFrog »

I may be mis-calculating but I thought my tank was just over 200 litres not 300? I've just posted a video on YouTube. I'm in a bit of a quandary as what fish would be suitable to keep if I was going to get a 3 beacon / blue phantom pleco. The ghost knife is getting bigger all the time and the common pleco isn't staying forever unfortunately. I didn't buy it - it was given to me in a 2 foot tank which wasn't right!


Also check out my other video 'another fishy tale' it's how my tank looks now!

[Mod edit: Use youtube tags --Mats]
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Re: Undergravel Filtration?

Post by MatsP »

If we convert the size of your tank to centimeters, it is 101 * 50 * 60cm = 303000 cm3 = 303 liter. (Obviously, with a bit of glass thickness and not filling the tank to the very top, you probably end up with about 260-280 liter of actual water, sand and decorations). Of course, that assumes you got the numbers right.

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Re: Undergravel Filtration?

Post by Jackster »

MatsP wrote:And undergravel filters are probably not the greatest idea for plecos anyways. The principle of pulling all the dirt into the surface on which the fish tends to spend most of its time seems to be a poor solution, in my mind.
--
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I totally disagree. I know undergravel filters are "old fashioned" but I have been
using them for over 20 years with excellent results. I also would seriously warn
against any type of central water flow system for plecos since any parasites
introduced will result in contamination of the entire system. Undergravel filters
also need supplemental filtration and I don't feel they will solely support any tank
or system. I know compared to some of my pleco breeding buddies, I get away
with higher stocking rates, (normally) less fry deaths, and fewer water changes
compared to sand or bare bottom tanks. And if you buy wild fish, separate tanks
are definitely the best and my preference is undergravel plates in every one,
however, most of the breeders I buy from (and sell to) use bare bottom (separate)
tanks using either multiple sponge filters or very "old school" box type filters
combined with a large central air flow system to run all of the tanks. This also
requires diligent water changes and frequent cleaning of the sand or bare bottoms.
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Re: Undergravel Filtration?

Post by racoll »

Jackster wrote: I totally disagree. I know undergravel filters are "old fashioned" but I have been
using them for over 20 years with excellent results. I also would seriously warn
against any type of central water flow system for plecos since any parasites
introduced will result in contamination of the entire system. Undergravel filters
also need supplemental filtration and I don't feel they will solely support any tank
or system. I know compared to some of my pleco breeding buddies, I get away
with higher stocking rates, (normally) less fry deaths, and fewer water changes
compared to sand or bare bottom tanks. And if you buy wild fish, separate tanks
are definitely the best and my preference is undergravel plates in every one,
however, most of the breeders I buy from (and sell to) use bare bottom (separate)
tanks using either multiple sponge filters or very "old school" box type filters
combined with a large central air flow system to run all of the tanks. This also
requires diligent water changes and frequent cleaning of the sand or bare bottoms.
We are not really discussing how to set up a filtration system for multiple tanks, or a pet store. Going off topic like this is quite likely to confuse the OP.

For the home catfish aquarium I wouldn't recommend undergravel either, mainly for the reason that it's really hard to keep clean with all the ornaments etc. Decent sized external filters are the only way, really, for a well stocked tank.

I would also agree that coral sand is a very bad idea. If I recall correctly, Sheffield has really nice soft water coming off the moors, perfect for your South American and Asian fishes. FunkyFredFrog, do you have any pH hardness readings for your tapwater?
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Re: Undergravel Filtration?

Post by FunkyFredFrog »

What's an OP? I guess that's me / the person who asks the question?

The ph test I use went as blue as possible. I tested the tap water and it's the same. At least 7.6. Is that soft or hard / acid or alk?
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Re: Undergravel Filtration?

Post by racoll »

What's an OP? I guess that's me / the person who asks the question?
OP stands for "original poster", i.e. you. It annoys me when people use unnecessary jargon and abbreviations I don't understand, so sorry about that.
The ph test I use went as blue as possible. I tested the tap water and it's the same. At least 7.6. Is that soft or hard / acid or alk?
The pH of the tapwater won't tell you all that much. Soft water is often still slightly alkaline (pH above 7) out of the tap anyway. Water companies don't want acid water dissolving their pipes, so they often put a bit of calcium carbonate into the soft water supplies.

Does the kettle fur up with limescale like it does is the South of England?
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Re: Undergravel Filtration?

Post by Jackster »

Well it's certainly possible to remove and replace the sand with gravel (with or without an undergravel filter) because I've done it several times. The best tool to remove sand is a kid's plastic toy shovel that is flat. I confiscated my son's years ago, and although he was a bit upset at the time, I don't think he cares anymore now that' he's older.

There has always been and will always be two sides to the whole undergravel filter story, but I have found that they give the hobbyist a little extra insurance if something happens to go wrong with the water quality of your aquarium. I don't see what issues would arise with undergravel filtration for the home aquarium since I tear apart my tanks frequently to move fry, breeders, and to catch fish for shipping and cleaning gravel is necessary anyway whether one has an undergravel plate or not so I don't really see the difference. Undergravel filters can get clogged eventually but it takes years and then an occasional tank breakdown for a 100% cleaning is probably a good idea anyway. Obviously as I mentioned before some type of supplemental filtration such as an external canister filter or multiple HOB filters would be required regardless.
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Re: Undergravel Filtration?

Post by FunkyFredFrog »

Jackster...would it be a complete no no to take the sand out while the fish are still in the tank. I can't think it would be good for them!

Yes we do get limescale in our kettles! My wife says she thinks it's not soft...maybe slighty hard.

Gosh..isn't getting a new tank just the start of an addiction!? Lol! I just love my fish!
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Re: Undergravel Filtration?

Post by racoll »

Yes we do get limescale in our kettles! My wife says she thinks it's not soft...maybe slighty hard.
That's okay then, there should be enough buffering capacity in your water to do without the coral sand.
.would it be a complete no no to take the sand out while the fish are still in the tank. I can't think it would be good for them!
It'll be better in the long term to get rid of the coral sand. It sounds like a nightmare, but it's not really.
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Re: Undergravel Filtration?

Post by MatsP »

You can quite easily replace the substrate (sand/gravel).
The process goes a bit like this:
Get a bigger hose than your average gravel cleaner, about 2m length.
Use the hose to "hoover" up your gravel/sand.
You'll probably want to do this at the water-change time, and perhaps over two-three times (you can change water every day if, you have similar tap-water to your tank-water).
Once you have removed a part of sand/gravel, add new sand/gravel.
Obviously, if you want to get a undergravel filter, then you'll need to clear enough space for the UGF-plate.

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Re: Undergravel Filtration?

Post by FunkyFredFrog »

Whats the right type of sand look like then? It's a bit confusing! I have some black gravel...maybe I could mix this with another dark colour for an interesting effect...
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Re: Undergravel Filtration?

Post by racoll »

Whats the right type of sand look like then? It's a bit confusing!
As Mats said, "play sand" from a DIY shop will be the cheapest option. You can also get inert aquarium sand from your local fish shop (LFS), but this will cost more. These will be your easiest options.

Be sure to wash any new sand really, really, really thoroughly before use.
have some black gravel...maybe I could mix this with another dark colour for an interesting effect...
Why not. A mix of substrates is good, but make sure you test it out first before you commit. It might look awful!
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Re: Undergravel Filtration?

Post by FunkyFredFrog »

Jackster wrote:
MatsP wrote:And undergravel filters are probably not the greatest idea for plecos anyways. The principle of pulling all the dirt into the surface on which the fish tends to spend most of its time seems to be a poor solution, in my mind.
--
Mats
I totally disagree. I know undergravel filters are "old fashioned" but I have been
using them for over 20 years with excellent results. I also would seriously warn
against any type of central water flow system for plecos since any parasites
introduced will result in contamination of the entire system. Undergravel filters
also need supplemental filtration and I don't feel they will solely support any tank
or system. I know compared to some of my pleco breeding buddies, I get away
with higher stocking rates, (normally) less fry deaths, and fewer water changes
compared to sand or bare bottom tanks. And if you buy wild fish, separate tanks
are definitely the best and my preference is undergravel plates in every one,
however, most of the breeders I buy from (and sell to) use bare bottom (separate)
tanks using either multiple sponge filters or very "old school" box type filters
combined with a large central air flow system to run all of the tanks. This also
requires diligent water changes and frequent cleaning of the sand or bare bottoms.
What are you referring to when you say central water flow? I have a small pump creating better circulation of water and waste / trying to mimick faster flowing rivers for the snowball pleco in particular.

Cheers for all the help folks!
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Re: Undergravel Filtration?

Post by racoll »

What are you referring to when you say central water flow?
Jackster's talking about multiple tanks with a single, centralised filter, like in the aquarium shops or some fish rooms.

I [correctly] suspected it might confuse matters slightly, which is why I suggested we stick to the topic in hand, i.e. your single tank.
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Re: Undergravel Filtration?

Post by MatsP »

Central filtration is when you have ONE filter for multiple tanks, which is (often) how fish shops works. And I talked about that, because you asked "How do fish-shops filter their tanks". I didn't suggest you do this!

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Re: Undergravel Filtration?

Post by Jackster »

And the only reason I mentioned a centralized system is because I've been there, done that, and it was a total disaster when it came to disease and parasite control. A circulating pump in a single tank is not a problem at all and I personally prefer current in my tanks, however, a couple of my breeder buddies have clearly proven that current is not necessary to spawn some of the more challenging species of plecos.
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Re: Undergravel Filtration?

Post by FunkyFredFrog »

I did get some new gravel but I'm going to wait for a while and see what happens. Can you run undergravel AND an external filter?

I've been looking at making a powerhead filtration system but not sure how it all fits together. Anyone help / got a good article on it?
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Re: Undergravel Filtration?

Post by Jools »

I've used UGFs a lot with plecos and a few other cats but run them with powerheads. I've not used air driven UGFs in 25 or so years - I use air driven sponges as the fry can eat off the sponge.

With non-wood eating plecos it works quite well although you do have a fair bit of maintenance. For me (30+ individual tanks) it's just easier to use internal or external power filtration for similar conditions for the fish. In tanks wider than 12" I found UGFs to be less effective and I use one powerhead per 18"x12" surface.

I got the best results with reverse UGF and external filtration in terms of minimising filter maintenance and ran a few tanks like this for years. However, it was just easier to swap out the UGF filters with internals.

Depth and grain size of substrate is also important with UGFs, I mostly used pea sized gravel about 4" deep.

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