Replacing Filter

[Fox46]

I am looking to replace one of my old filters in an established fully cycled tank, so I have installed the new filter running alongside the old one, and removed one of the sponges from the old filter and put it in the new, so both filters are now working with one old, one new sponge. The new filter media, polycarbon pads and remaining new sponge were rinsed and soaked in used filter debris water for a short while before inserting.

How long would you think before the new filter is fully seeded and fit for functioning on its own.

 

[gwand]

I’m doing the same thing at the moment. I plan on running the new filter for one month before removing the old filter.

 

[Fox46]

I’m doing the same thing at the moment. I plan on running the new filter for one month before removing the old filter.

Yes, that was about where I was thinking, though I'd have hoped it might be sooner. Thanks

 

[TwoTankAmin]

I have not so much replaced entire filters as i have upgraded the media. I am a big fan of foam media as it does both bio and mechanical filtration. I also became a huge fan of Poret foam about 14 years ago. I used to have about 28 running Aquaclears of all sizes and it has been moistly in them I have change from th AV foam to the 20 ppi Poret. Here is how I do it.

I cut the Poret foam to size so it matched the size of the AC foam. I then remove the AC foam and replace it with the Poret. In order not to have an ammonia etc. spike I then put the AC foam into the tank. I want to avoid putting near the outflow of the filter. What then will happen is the bacteria in the AC foam will beging to decrease in number while new bacteria will start to colonize the Poret. This happens because there is better circulation in the filter and thus to through the new Poret than where the AC foam is in the tank.

Because the ammonia load is not changed the net result is more bacteria will build up in the new foam as a similar amount dies off in the the old foam. I usually leave the old AC foam in the tank for about two weeks and then I remove it first dqueezing it out in the tank water with the goal of trying to lave any of the bacteria I squeeze out behind.

While the bacteria is mostly in a bio-film in the media, the substrate and on other hard surfaces in a tank in places where light is minimal, some amount of the bacteria is actually in the water. It is there naturally as part of the long term survival strategy of the bacteria. How much might be "free swimming" depends in the amount of nitrogen available. If the ammonia were disappear the bacteria uses two strategies to survive this. Most of it will go into a state of dormancy where it can survive for a decent amount of time and will wake back up when ammonia returns.

The amount of bacteria in the water will increase to as much as 10% of the total under the lowest nitrogen levels since its job is to increase the chance that some will succeed in moving to another location where ammonia may be available. Normally, the amount that is mobile is usually way less than 10% but it is never none.

This works great in nature where there are other places for the free swimming bacteria to go where it would then also be able to reproduce due to the availability of ammonia. In our tanks there is no place else for it to go. But that free swimming bacteria will get into the new foam where it will attach. As the amount of bacteria in the old foam decreases the bacteria in the new foam will reproduce because it is getting the ammonia that the decreasing amount of bacteria in old foam can no longer can process.

All of this is happening on the microscopic level. We cannot see it happening. How we know it is doing so is clear when we test durnig the whole change over process. So, we should not see an ammonia spike. What appear to be happening is the bacteria moves from one foam to the other. The fact is what is actually happening is what I described above.

What I would advise is one should remove the old filter, leaving its bio-media behind in the tank water. The new filter just goes onto the tank and a new colony will become established. Of course, even better is when we can move the old bio-media out of the old filter and then put it into the new one. That allows us to remove the old filter and add the new one with the old media and there is no need for the more elaborate process I have described. But when this is not possible, then using the method above leaving the old media behind in the tank is the next best option.

I have done this multiple times over the years and I never have gotten an ammonia spike. It works so well that I stopped testing for ammonia during the change over because I know how it will go. If you want to try this, you should test so you can see how it goes for your own peace of mind. Even if you do see a low level of ammonia when testing, it will not last very long and will not be enough to cause harm to the fish.

Because the bulk of the needed bacteria is immobile it will always do best where the ammonia, oxygen and a few other things are delivered to it regularly without much change. The total amount of nitrifying bacteria in a tank will always be determined by the ammonia level available. If this increases then the bacteria will reproduce to handle it. If the ammonia level decreases then the natural death rate of the bacteria will be greater than the rate of reproduction and the total amount of bacteria will decrease until it is again in balance with the lower ammonia level.

 

[Fox46]

I have not so much replaced entire filters as i have upgraded the media. I am a big fan of foam media as it does both bio and mechanical filtration. I also became a huge fan of Poret foam about 14 years ago. I used to have about 28 running Aquaclears of all sizes and it has been moistly in them I have change from th AV foam to the 20 ppi Poret. Here is how I do it.

I cut the Poret foam to size so it matched the size of the AC foam. I then remove the AC foam and replace it with the Poret. In order not to have an ammonia etc. spike I then put the AC foam into the tank. I want to avoid putting near the outflow of the filter. What then will happen is the bacteria in the AC foam will beging to decrease in number while new bacteria will start to colonize the Poret. This happens because there is better circulation in the filter and thus to through the new Poret than where the AC foam is in the tank.

Because the ammonia load is not changed the net result is more bacteria will build up in the new foam as a similar amount dies off in the the old foam. I usually leave the old AC foam in the tank for about two weeks and then I remove it first dqueezing it out in the tank water with the goal of trying to lave any of the bacteria I squeeze out behind.

While the bacteria is mostly in a bio-film in the media, the substrate and on other hard surfaces in a tank in places where light is minimal, some amount of the bacteria is actually in the water. It is there naturally as part of the long term survival strategy of the bacteria. How much might be "free swimming" depends in the amount of nitrogen available. If the ammonia were disappear the bacteria uses two strategies to survive this. Most of it will go into a state of dormancy where it can survive for a decent amount of time and will wake back up when ammonia returns.

The amount of bacteria in the water will increase to as much as 10% of the total under the lowest nitrogen levels since its job is to increase the chance that some will succeed in moving to another location where ammonia may be available. Normally, the amount that is mobile is usually way less than 10% but it is never none.

This works great in nature where there are other places for the free swimming bacteria to go where it would then also be able to reproduce due to the availability of ammonia. In our tanks there is no place else for it to go. But that free swimming bacteria will get into the new foam where it will attach. As the amount of bacteria in the old foam decreases the bacteria in the new foam will reproduce because it is getting the ammonia that the decreasing amount of bacteria in old foam can no longer can process.

All of this is happening on the microscopic level. We cannot see it happening. How we know it is doing so is clear when we test durnig the whole change over process. So, we should not see an ammonia spike. What appear to be happening is the bacteria moves from one foam to the other. The fact is what is actually happening is what I described above.

What I would advise is one should remove the old filter, leaving its bio-media behind in the tank water. The new filter just goes onto the tank and a new colony will become established. Of course, even better is when we can move the old bio-media out of the old filter and then put it into the new one. That allows us to remove the old filter and add the new one with the old media and there is no need for the more elaborate process I have described. But when this is not possible, then using the method above leaving the old media behind in the tank is the next best option.

I have done this multiple times over the years and I never have gotten an ammonia spike. It works so well that I stopped testing for ammonia during the change over because I know how it will go. If you want to try this, you should test so you can see how it goes for your own peace of mind. Even if you do see a low level of ammonia when testing, it will not last very long and will not be enough to cause harm to the fish.

Because the bulk of the needed bacteria is immobile it will always do best where the ammonia, oxygen and a few other things are delivered to it regularly without much change. The total amount of nitrifying bacteria in a tank will always be determined by the ammonia level available. If this increases then the bacteria will reproduce to handle it. If the ammonia level decreases then the natural death rate of the bacteria will be greater than the rate of reproduction and the total amount of bacteria will decrease until it is again in balance with the lower ammonia level.

That’s a very comprehensive response – thank you. And in part I think that last paragraph may explain something that happened prior to my deciding to get a new filter.

I had a population explosion in my bigger tank, as a result of an initial purchase of 1 male swordtail and 5 females turning into 3 males and 3 females, the latter transformations going unnoticed by me initially. So I segregated the 3 males into a smaller 60l tank which I furnished with 2 x 25litre sponge spray-bar type filters from my big tank (which I run in there as a supplement just for water agitation and to be able to immediately set up a 25l hospital tank should it be needed as an emergency. )

I assumed that with only 3 fish in the new tank, an initial water fill-up comprising 50% old tank water, some tank furniture and plants from the old tank and the 2 fully seeded 25l filters I would be pretty safe to assume that water parameters would remain consistent in the newly set-up tank. This proved not to be the case, though thankfully nothing drastic as I immediately started testing the parameters after the transfer and saw a concerning change. But for several days I had to do 50% water changes and test the parameters twice daily while the cycle re-stabilised itself. I’m guessing therefore that the reduction in ammonia level in this new tank caused a hiccup with the existing bacterial load, as mentioned in your last paragraph.

Anyway, all’s well now. I probably won’t take out the media from the old filter in the big tank, as once the new one is up and running I intend to transfer that old one into the 60l tank, so I can restore the 2 x 25l filters back to the bigger tank.

It’s all a bit like a game of chess!

Thanks for your response.

 

[AJ356]

Sorry if this has already been covered above, but just so you know, one thing to always bear in mind is that on any given mature sponge, there is not necessarily the same amount of beneficial bacteria on each sponge or part of the sponge.

This might not apply to you, as you are using all your mature sponges at the moment.

It more applies if someone cuts off part of a mature sponge thinking it will definitely contain roughly the same amount of beneficial bacteria to the rest of the sponge.

What I mean by that is that half of a big mature sponge might instantly cycle a small tank with 10 small fish, while the other half of that same sponge in an identical small tank with 10 small fish might not have enough beneficial bacteria to prevent an accidental fish-in cycle (I.e. ammonia and nitrite problems)

This different if you have a good amount of live plants that are growing in a tank, because that can reduce the dependency on mature filter media in these scenarios

 

[AJ356]

Also, be aware that even in one month, there might be very little build up of beneficial bacteria on the new sponges.

This is because, if the old sponges are very mature and housing enough beneficial bacteria to process all the ammonia into nitrite and then nitrate, there will be no need for more beneficial bacteria to start multiplying in great numbers on the new sponges. I think eventually maybe, but not in a month.

In your case, I would just keep the old mature sponges in the new filter, and keep the new sponges as spares, unless you are concerned the old sponges are so old they are falling apart?

I literally can go 2, to even 5 years easy with the same filter sponges in a tank and they work just as well as new mature sponges in terms of handling ammonia and nitrite.

 

[AJ356]

If you have very mature filter media, it's worth it's weight in gold. Be careful in making any decision to replace old filter media with new, even if you are trying to do it skillfully. Mature media is more than just an ammonia and nitrite eliminator.

 

[AJ356]

Squeezing the old sponges into the tank water is better than getting rid of the old sponge altogether.

But i believe from my testing over the years that sponge squeezing is not quite as effective as some might think, but its definitely better then nothing and has helped speed up my cycles, and helped somewhat in an emergency

I say this because I think people probably overestimate how much beneficial bacteria actually simply falls off because the sponge is squeezed. I think its harder to get the bacteria off a sponge than we probably think.

Also, I am pretty convinced quite a small amount of beneficial bacteria that goes in the water from a squeeze, ends up sticking to the new media. Some does obviously.

I am also a believer that beneficial bacteria is NOT present in enough quantity to make any real difference unless its ON the filter media. This talk of beneficial bacteria floating around in the water column, being on the glass, the decor, the substrate. Probably true, but in a non planted aquarium, if you turn off your filter and just use an airstone, you will quickly see how helpful all this other beneficial bacteria is that is not on the filter, and the answer is NO HELP AT ALL !!!

 

[Fox46]

Squeezing the old sponges into the tank water is better than getting rid of the old sponge altogether.

But i believe from my testing over the years that sponge squeezing is not quite as effective as some might think, but its definitely better then nothing and has helped speed up my cycles, and helped somewhat in an emergency

I say this because I think people probably overestimate how much beneficial bacteria actually simply falls off because the sponge is squeezed. I think its harder to get the bacteria off a sponge than we probably think.

Also, I am pretty convinced quite a small amount of beneficial bacteria that goes in the water from a squeeze, ends up sticking to the new media. Some does obviously.

I am also a believer that beneficial bacteria is NOT present in enough quantity to make any real difference unless its ON the filter media. This talk of beneficial bacteria floating around in the water column, being on the glass, the decor, the substrate. Probably true, but in a non planted aquarium, if you turn off your filter and just use an airstone, you will quickly see how helpful all this other beneficial bacteria is that is not on the filter, and the answer is NO HELP AT ALL !!!

Thanks for those responses. It's tricky isn't it? My aim is not to replace the old filter in its entirety, but to eventually utilise it in the other tank that I've had to set up, after I've used it in the most effective way to get its replacement working in the shortest time possible. Hence the partial removal/sharing of component parts in a manner which I hope doesn't compromise its effectiveness in its current tank (which is heavily populated) yet facilitates its best contribution to the set up of the new filter that will replace it.

 

[TwoTankAmin]

One more observation that is failed to mention in my post related to leaving the old sponge in the tank instead of the old filter.

The filter worked as it does in terms of supplying the bacteria with what they need because there is a constant circulation of new water which contain the ammonia, oxygen and the other things the bacteria needs to thrive. When I move the pold foam into the tank it is no lnger getting that flow of nutrients. However, it is getting some of them but at a greatly reduced level. The new media in the new filter now has the best supply of what the bacteria will need. The result is the old foam begins to lose bacteria while the new one begins to have whatever bacteria it starts with begining to multiply. And this will happen at the best possible rate. In one 24 hour period this means the number can double in as few as 8 hours. And this works in a similar fashion to how investments benefid from compounding.

If there are only 100 bacterium in the new foam after 8 hours there would be 200. In another 8 hours that number becomes 400 and at the end of one day that number becomes 800, This is a bit of an over simplification but it is a fair explanation of how it works, The reality is the number or individuals involve is much greater. Taking it a step further on day 2 the numbers go to 1,600 then 3,200 and then to 6,400.

This also explains why using something lke Dr. Tim's One and Only can help get a tank cycled pretty fast. What matters is how much bacteria one might have in a tank to start. It is also why rinsing out the old media in the tank helps more than some folks understand is possible. I f all that comes out of the old foam is just 5% of the bacteria the same math works, 5% could ecome 10% then 20% and finally 40% at the end of one full day. And by day 2 you hit the 100%. However, the realty is that it will not happen that fast because the old foam now in the tank will still be using some of the nutrients and this means there will be less that all the nutrients available to double the bacteria in the new foam.

However, the more of that bacteria that develops in the new foam, the less that there will be for the old foam's residents to have. And this means the dying back process will accelerate. As I said this is an over simplification but it should give one an idea of theow the process basically works. And we shuld not forget that there is bacteria at work all over a tank. it is in the top portion of the substrate and on other hard surfaces as well. Circulation and being out of the light will influence all of this.

What matter is what ammonia levels one can test and how the readings will change over time.By time we are talking about a few days not weeks etc. What matters most in all of this bacterial relocation and the risk from any ammonia reading is how much of the total ammonia is in the toxic NH3 form. As long as this number for this does not manage t get much over 0.05 ppm. the fish can be OK in readings fot total ammonia as high as 2 ppm for a short time. Think a few days or even a week for most fish.

My numbers for the danger levels are quite conservative. I reached them with the goal of protecting even the more sensitive fish. I do this because I cannot be certain of what specific stock any given keeper may have in their tank. It is also why the fishless cycling article here uses 4 ppm of ammonia when adding to a tank being cycled without fish and then allowing one to fully stock a tank in one go. I do not know how many fish nor what species and sizes they might be. Nor do I know the specific parameters in any tank might be either. The higher the pH and temperature of the water, the more of any total ammonia reading will be in the NH3 form.

What this means is that 3 ppm is more often than not a greater level than many tanks might need to produce sufficient bacteria for the given parameters and stocking specifics one has, What is needed is that the 3 ppm level will protect the highest risk situations which can occur and will not matter in cases where it is more than needed. The cycling method used here is intended to protect in all parameters and all stocking levels as long as these are not gross overstocking.