Filtration question

[Fishy Smell]

Up until recently I had 2 filters running on my 55 and the same on my 48. I removed one filter on each because I felt that the current was a bit much for some of the fish and my stock levels didn't particularly need double filtration anyway. On both tanks the filtration was double the recommended before I took one on each away. I thought it would be ok because the remaining should have been enough. I had a fairly significant ( but not quite dangerous) ammonia spike on the 55, and a slightly raised ammonia level in the 48 (which is quite lightly stocked). I have lost a couple of the more sensitive fish on the 55, and have been performing water changes daily and rinsed a couple of filter sponges out of my 130 into the water to get some more bacteria in there. The levels are slightly better this morning but still present. I'm going to get some of that tank starting bacteria you can add to new tanks as well to help more.
My question is, because I've thought of this after; presumably there was only enough beneficial bacteria in the tank to cater for the fish in there (makes sense in hindsight) and me removing a filter halved the bb available for the quantity of fish I had (rather than me thinking that there was twice the bb I needed in the tank so if I take one away there will still be enough!!
Presumably if true, this means that over filtration is pointless (to an extent) unless you are overstocked?
Any feedback from filtration experts would be most welcome.



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[Delapool]

That makes sense to me. Conversely, if you had same filters but doubled your stocking you may get a mini-cycle until bb can catch up.

However, I've done the same (well, the filter was cleaned in tap water -yes, I know, I know; and then put back in). No ammonia spike. I can only assume some bb survive in the ceramic biomedia and these catch up fairly quickly.

The only time I've had an ammonia spike was when I was basically running a single filter and had to clean it 3 times in a month as the impeller got blocked. I run 3 filters now so that isn't a problem but have been stuffing more filter wool into them until I get the flow I want. Some thoughts anyways.

 

[BBradbury]

Your Tanks

Up until recently I had 2 filters running on my 55 and the same on my 48. I removed one filter on each because I felt that the current was a bit much for some of the fish and my stock levels didn't particularly need double filtration anyway. On both tanks the filtration was double the recommended before I took one on each away. I thought it would be ok because the remaining should have been enough. I had a fairly significant ( but not quite dangerous) ammonia spike on the 55, and a slightly raised ammonia level in the 48 (which is quite lightly stocked). I have lost a couple of the more sensitive fish on the 55, and have been performing water changes daily and rinsed a couple of filter sponges out of my 130 into the water to get some more bacteria in there. The levels are slightly better this morning but still present. I'm going to get some of that tank starting bacteria you can add to new tanks as well to help more.
My question is, because I've thought of this after; presumably there was only enough beneficial bacteria in the tank to cater for the fish in there (makes sense in hindsight) and me removing a filter halved the bb available for the quantity of fish I had (rather than me thinking that there was twice the bb I needed in the tank so if I take one away there will still be enough!!
Presumably if true, this means that over filtration is pointless (to an extent) unless you are overstocked?
Any feedback from filtration experts would be most welcome.



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Hello Fishy...

A water change prior to removing the extra filter would have avoided the sudden rise in nitrogen. I keep the same sized tanks you have and change half the tank water weekly to keep the tank water cleaner. I only have one filter with a gph (gallon per hour) rating 4 times the volume of the tank. That's plenty for the amount of new water that goes into the tank. Large, frequent water changes will take the place of a filter. The reverse however, isn't true. We live and learn.

The good bacteria lives on surfaces inside the tank. There's very little bacteria in the old water. There's nothing for the bacteria to hold on to.

I believe you're essentially right about overfiltration. If you you're an aggressive water changer (I'm one), you don't need a lot of filtration. The water is already clean, so the filters are simply moving pure water. Seems like a waste to me too. But, if you're a member of the "Water Change Slackers' Club", you'll need high end filters and a lot of them, to even begin to keep the tank water safe for the fish.

Keep pluggin',

B

 

[Fishy Smell]

Thanks for the replies. Yeah, had no water issues for over 12 months till now, definitely a miscalculation on my part with this. Need to concentrate on getting everything normal again and might replace a couple of the ones I lost.
You live and learn.


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[dalto]

My question is, because I've thought of this after; presumably there was only enough beneficial bacteria in the tank to cater for the fish in there (makes sense in hindsight) and me removing a filter halved the bb available for the quantity of fish I had (rather than me thinking that there was twice the bb I needed in the tank so if I take one away there will still be enough!!
Presumably if true, this means that over filtration is pointless (to an extent) unless you are overstocked?
Any feedback from filtration experts would be most welcome.

Yes, you probably removed about a good bit of you BB but in an established tank the results should not be that drastic. You should have seen no more than a small mini-cycle.

Something else must be going on. Some potential ideas:
- Something disrupted the other filter, a cleaning, a replacement filter pad, etc
- All of your BB was in the filter you removed.(Highly unlikely, IMO)
- Your current bio-filtration is not enough to handle the tank or their isn't enough bio-media.
- Something else happened to destroy all the BB. This seems fairly unlikely.

 

[PB_Smith]

There is no such thing as over filtration, especially biological.
I purposely set my tanks up so the bio filter could easily support 4-5 times the load I put on them.
Bacteria will go dormant or lower metabolism if not enough nutrients are present, but they don't really die off. With that fact in mind than it makes good sense to provide AS MUCH potential for the bacteria as possible to flourish in your set-up.

The fact that everything went south after removing the filters tells you right there that your tanks WERE NOT over filtered, if anything the opposite was/is true, they are under filtered, otherwise you would not have had the spikes you encountered.

Just about every HOB filter I have seen provide a woeful amount of filtration potential for the rated water volumes. I actually was laughing reading the specs of a AC 110 the other day at the store, what a joke. If using any of the popular HOB type filters, I would definitely double up on them at least.

 

[gilpi]

In case I missed it, what filters do you have in the 55?

 

[Fishy Smell]

Standard filter system integrated into frf2100 tank (210 litres), includes bio balls, active carbon and sponges for chemical, biological and mechanical. + eheim 2012 pickup, good for up to 200 litres apparently. That was the one i took out.

I do appreciate the feedback from everyone but there is no way i was even close to underfiltered beforehand. If someone wants to tell me that my theory regarding there being just enough good bb for the bioload and me removing half of it (rather than there being twice as much bb as i needed and me removing half of it, therefore still having enough) is wrong, then i'm curious to hear more on that.

I used to run the tank with a similar bioload on the integrated filter alone and had very few problems. I decided to put another one in originally purely to improve water quality further and as back up incase the integrated one failed.

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[dalto]

If someone wants to tell me that my theory regarding there being just enough good bb for the bioload and me removing half of it (rather than there being twice as much bb as i needed and me removing half of it, therefore still having enough) is wrong, then i'm curious to hear more on that.

It isn't wrong. It just shouldn't have caused this big of a problem in an established tank. That is what it concerning to me personally.

 

[gilpi]

Stick to water changes for now and make sure you have good flow through the filter for now, that's the oxygen the BB needs. Over feeding and overstocking could be a problem, what fish do you have?

 

[Fishy Smell]

Yeah, i know it seemed strange. That was why i racked my brains thinking about the cause and came up with the theory. The main thing i was trying to take from posting on here was finding out from someone who knows more about cycling and filters than me, whether my theory was correct in theory
Still interested to know if anyone else has a take on it....?


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[Fishy Smell]

Stick to water changes for now and make sure you have good flow through the filter for now, that's the oxygen the BB needs. Over feeding and overstocking could be a problem, what fish do you have?

Not feeding them at the moment. 5 midsized cichlids, 10 tiger barbs and a few bottom dwellers, a couple of which ive lost.

I should point out again that the ammonia wasn't quite in the toxic zone, when relating to my ph level. Its just that it wasn't far away from it and i lost a couple of sensitive fish that probably cant cope with any. The levels are now starting to drop, and are well away from the 'toxic zone'.

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[Masha]

I suspect it might have more to do with removing the filter media (and the bacteria it held) than removing the filter.

The amount of bacteria is determined by the amount of food for them, and if you have 2 filters, that bacteria is shared between the two lots of filter media. Remove a filter = removing half of the bacteria colony.

Some say that there is more bacteria in the rest of the tank than in the filter. I say that must depend from tank to tank, and in this case, probably there was enough bacteria in the filter for the loss of them to make a difference

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[Fishy Smell]

Thanks Masha, i think you've confirmed what i thought about an optimum level of bb being split between the two filters, hence the problem. There is no ammonia present now in this tank or the other one which had a minor issue, will start feeding in very small quantities and build up slow.
Its always useful when you have multiple tanks, i think rinsing sponges from the 130g has resolved it quite quickly.


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[Delapool]

Only other thing I could think of was if you had low ph slowing down bb activity but assumed you had it covered.

 

[Fishy Smell]

Ph is 7.5. Put some 'cycle' bacteria stuff in both today, just to make sure.


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[Delapool]

Covered