Internal to external filter

[Darter217]

After a month or so of having my tank up and running with fish and after doing a bit of research I've noticed that upgrading to an external filter has quite a new benefits. Especially when it comes to increasing your stocking. So I have some questions about it.

How do you deal out your filter sponges and media from your internal to your external (I have a fluval U3)

Because I have a fluval filter, would I also have to get a fluval external filter?

I have a 125 litre tank, should I go for the fluval 207 or 307 (if I choose a fluval external)

 

[Darkomot]

When you say external filter, do you mean a canister filter? The filter that you have now should handle a healthy stocking amount for the tank. Lastly, the filter media in your internal filter (the sponge, or other things inside of the filter) can easily be moved into another filter if you chose to do so. What fish do you have, and what fish are you planning to add? This will help decide if you actually need to switch to an external filter.

 

[seangee]

I'm afraid the idea that you can buy a bigger filter and then house more fish is a load of old ****. The U3 is a good filter for your tank size. Changing the filter won't make the tank any bigger. If you want to push how many fish you keep plants (lots of them) are a far better option as this provides shelter and hiding spaces for fish (from each other) and are a far more effective way of increasing water quality.

If you double your filter capacity in order to double your "stock limit" you end up with an overcrowded tank full of stressed fish. They won't adapt to overcrowding so ultimately you end up with unhealthy (and later dead) fish.

 

[Darter217]

I'm afraid the idea that you can buy a bigger filter and then house more fish is a load of old ****. The U3 is a good filter for your tank size. Changing the filter won't make the tank any bigger. If you want to push how many fish you keep plants (lots of them) are a far better option as this provides shelter and hiding spaces for fish (from each other) and are a far more effective way of increasing water quality.

If you double your filter capacity in order to double your "stock limit" you end up with an overcrowded tank full of stressed fish. They won't adapt to overcrowding so ultimately you end up with unhealthy (and later dead) fish.

Oh I wasn't planning on overstocking my tank, I was just concerned that my current filter won't be enough for the fish I want to keep. Also heard that external filters are just better in general.

 

[Darter217]

When you say external filter, do you mean a canister filter? The filter that you have now should handle a healthy stocking amount for the tank. Lastly, the filter media in your internal filter (the sponge, or other things inside of the filter) can easily be moved into another filter if you chose to do so. What fish do you have, and what fish are you planning to add? This will help decide if you actually need to switch to an external filter.

At the moment I have 9 five banded barbs, planning to add 5 Juli Cory's and 10 lemon tetras. The tetras will come in a few months once my tank has matured.

 

[Gypsum]

Externals look nicer than a big black box inside your tank, and it gives your fish a wee bit more space to swim. Or you run both because you feel better with redunancy in the system and it gives you more media to play around with when seeding other tanks. Anyway, the Fluval 207 is fine for 125L. If one fit into the awkward space around my 125L, that's probably what I would have. I have a 307 on the 240L.

You can take media out of the U3 and put it in the new external. The other thing lots of people do -- and that I would do -- would be running both at the same time for about two weeks. This gives bacteria a chance to fully colonize the new filter and reduced risk of a crash. I have also done water changes either every day or every couple days for a week, just to be safe. That might be overly paranoid, but I've changed a lot of filters and no one has died as a result of that yet.

 

[Darter217]

Externals look nicer than a big black box inside your tank, and it gives your fish a wee bit more space to swim. Or you run both because you feel better with redunancy in the system and it gives you more media to play around with when seeding other tanks. Anyway, the Fluval 207 is fine for 125L. If one fit into the awkward space around my 125L, that's probably what I would have. I have a 307 on the 240L.

You can take media out of the U3 and put it in the new external. The other thing lots of people do -- and that I would do -- would be running both at the same time for about two weeks. This gives bacteria a chance to fully colonize the new filter and reduced risk of a crash. I have also done water changes either every day or every couple days for a week, just to be safe. That might be overly paranoid, but I've changed a lot of filters and no one has died as a result of that yet.

Thanks for the detailed reply! Yeh I thought the 207 would be okay, the 307 would just be taking up extra space in the cabinet and uses more power and the 207 would already be overfiltering. I'll have to cut two squares into the lid of the 125 to fit the intake and outtake pipes in but that shouldn't be an issue, also how exactly would I go about swapping the filter sponges and media?

 

[itiwhetu]

I would never go back to external filters, I love internals. Firstly they are easier to maintain and secondly you have the added security of knowing that ever thing is contained in the tank. If anything put a second internal in to your tank.

 

[Gypsum]

Our 50-degree fish keeping learning curve involved a hell of a lot of tank upgrades and filter faff. We got really good at replacing filters and swapping fish to new tanks.

When we put an external -- an Oase Filtosmart 200, which is roughly the same capacity as a 207 but it fit under an oddly-shaped table -- on my 125 Fluval Roma, OH drilled holes in the lid. That's pretty straightforward.

To swap media, you take the sponges and whatever else out of the U3 and ram them into the 207. They'll be in the cartridge thingmes, so take them out of the cartridges. Sponges in U-series Fluvals aren't very big, so they can be crammed into most things. Sometimes, you will have to take a couple bits of sponge out of the new filter so the old media fits. That's fine. Then you have extra sponge lying around, which is useful when you have to baffle an intake or something. Sometimes, you have to mutilate sponges to make them fit. But that's fine too. That said, we didn't have to do much when we got the 307, as it was big enough to just throw whatever into it.

 

[Darter217]

Our 50-degree fish keeping learning curve involved a hell of a lot of tank upgrades and filter faff. We got really good at replacing filters and swapping fish to new tanks.

When we put an external -- an Oase Filtosmart 200, which is roughly the same capacity as a 207 but it fit under an oddly-shaped table -- on my 125 Fluval Roma, OH drilled holes in the lid. That's pretty straightforward.

To swap media, you take the sponges and whatever else out of the U3 and ram them into the 207. They'll be in the cartridge thingmes, so take them out of the cartridges. Sponges in U-series Fluvals aren't very big, so they can be crammed into most things. Sometimes, you will have to take a couple bits of sponge out of the new filter so the old media fits. That's fine. Then you have extra sponge lying around, which is useful when you have to baffle an intake or something. Sometimes, you have to mutilate sponges to make them fit. But that's fine too. That said, we didn't have to do much when we got the 307, as it was big enough to just throw whatever into it.

So you're saying that the U3 sponges would fit much easier into the 307 than the 207, makes sense. I take I'd just mix the old filter media in with the new filter media that comes with the new filter so that the bacteria would colonise on them too?

I'm considering the 307 purely because it would mean not having to upgrade my external filter when I eventually move up to a bigger tank with bigger fish.

 

[FFGuest6357]

I’m running a 207 on my 20gal long right now, more than enough, and it will be able to handle my upgrade to the 30gal.

how big are you looking upgrade your tank and can you not wait to get the new tank before you upgrade your filter?

 

[Fishmanic]

I run a HOB filter AND a sponge filter in each of my 3 tanks. If one fails, the other one will prevent a cycle crash. And having two, increases water circulation. And I have media for a hospital tank if needed in a pinch.

 

[FFGuest6357]

I don’t want to back and forth between gallons and litres.

the 207 is rated for tanks between 20 and 40gallons

the 307 is rated for tanks between 40 and 70gallons.

The way I would approach your situation is first decided what size you’re going to upgrade to, and choose your filter accordingly. But if you decide to go with the 307 because you want a bigger 50-75 gallons tank, just know that putting that filter on your 125L tank, which is approximately 33 US gallon, is going to be way overkill.

as mentioned I’m running the 207 on my 20 long and the flow rate is a little stronger than I would like. And my tank falls within the recommended size for the filter. If you want to go with the 307, you’re putting a filter on the tank that is meant to filter tanks 10-40 gallons larger than your current tank. it’s going to be moving a lot of water.

be diligent in your research. Either upgrade you filter when you upgrade size, or you could always go with the 207, which would be undersized for a 40-55 gallon, but there’s no reason you couldn’t run the hang on back as well. I’ve known people to run all of their biological media in a canister and run a hang on back with nothing but polishing media to keep water clear.

Good luck!

 

[Darter217]

I don’t want to back and forth between gallons and litres.

the 207 is rated for tanks between 20 and 40gallons

the 307 is rated for tanks between 40 and 70gallons.

The way I would approach your situation is first decided what size you’re going to upgrade to, and choose your filter accordingly. But if you decide to go with the 307 because you want a bigger 50-75 gallons tank, just know that putting that filter on your 125L tank, which is approximately 33 US gallon, is going to be way overkill.

as mentioned I’m running the 207 on my 20 long and the flow rate is a little stronger than I would like. And my tank falls within the recommended size for the filter. If you want to go with the 307, you’re putting a filter on the tank that is meant to filter tanks 10-40 gallons larger than your current tank. it’s going to be moving a lot of water.

be diligent in your research. Either upgrade you filter when you upgrade size, or you could always go with the 207, which would be undersized for a 40-55 gallon, but there’s no reason you couldn’t run the hang on back as well. I’ve known people to run all of their biological media in a canister and run a hang on back with nothing but polishing media to keep water clear.

Good luck!

My tank is slightly bigger than yours so the 207 should be fine, heard compelling arguments for a few options but I've got time to decide, although at the moment I'm leaning towards the 207.

 

[Gypsum]

I meant anything in the 07 series should take media from a smaller filter without too much faffing. They're pretty roomy inside.