# how to kill nitrifying bateria in cloth filter



## peridot (Feb 24, 2005)

Hello
I am running a nice Nano (12gal) El Natural and I have some mechanical filtration to keep the water looking pretty. Plants and fish are well but increasing amount of thread algae (cladophora?) The filter is just filter fabric sewn up into sock shape thru which water water is pumped. In the tank, pH has recently been rountinely going down and now I find that the nitrates are up to 18 ppm, so I suspect that the filter is hosting nitrifying bacteria. Normally I just rinse it out now and again. But to kill nitrifiers I think I might steam it in the microwave and rinse it again. If I use bleach, I have to worry about getting it all out again.....

What do you think?

Thanks

Peridot


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## Fortuna Wolf (Feb 3, 2007)

dude, what?
12 gallons is not a nano. 

If you kill the nitrifying bacteria (which is all over the tank) then you'll have ammonia and nitrate problems. And then the bacteria will recolonize anyway.


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## helgymatt (Sep 12, 2007)

The purpose of a filter is to provide a home for nitrifying bacteria to convert toxic ammonium to non-toxic nitrate. Just do a water change to reduce the nitrate! Some nitrate is ok. Killing those bacteria is the last thing you want to do.

I dought the nitrate or the pH has anything to do with the algae. Lighting and CO2 are more likely the cause of the algae.
Matt


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## peridot (Feb 24, 2005)

Sorry I wasn't clear. I don't mean killing all the nitrifying bacteria in the tank. I just don't want my mechanical filtration to turn into a defacto biological filtration. In this I am following Diana Walstad as closely as I can. "Aquatic plants prefer Ammonium over Nitrates" (page 107) I don't want a biological filter competing with the plants for ammonium (page 111) and driving the pH down. (page 112)


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## helgymatt (Sep 12, 2007)

Do you have a natural tank with soil substrate?


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## mistergreen (Mar 3, 2007)

don't worry about this... if there are no NH3/NH4, plants can use NO3.
And I'd assume, plants are much faster at consuming NH3 than bacteria.


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## peridot (Feb 24, 2005)

Yes, I have a natural tank with soil substrate, submerged and floating plants, no CO2, 2 watts per gallon. Basically I have a Walstad type tank. The algae is probably a secondary issue. The persistantly falling pH is more troublesome.

Peridot


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## will5 (Oct 26, 2005)

I think you need to do some more reading on El natrual tanks. There is no reason in the world ti kill good bacteria. I have an El natural tank and I run a filter on it with a sponge inside the tank on the intake and in the filter itself and I have never had a reason to kill this the bacteria. I think you should post over in the El natural form to try and get some help that way. If you lucky Walstad her self will reply.

Until you get some help I suggest you do a lot more reading in the El natural thread.


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## rohape (Feb 7, 2005)

Bleach kills everything. Just dump some in your tank, you'll be good. :lol:
Remove the 'sock'. See if you can get your hands on something more porous. A large prefilter where it would be harder for the bacteria to grow. I use a very porous prefilter in my power head, but thats just to catch large debris and is cleaned about every 2 weeks - 1 month under running tapwater.

_edit:_ DON'T DUMP THE BLEACH IN YOUR TANK! :mrgreen:


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## peridot (Feb 24, 2005)

Isn't this the El natural forum!?

Ms Walstad, can you help us? Persistently falling pH is the trouble I am trying to fix. If reducing my population of nitrifying bacteria helped calm down the algae that's good too.

Many thanks

Peridot


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## mistergreen (Mar 3, 2007)

A water change? That'll help with ph.
I don't know how you're connecting n-bacteria with algae.


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## rohape (Feb 7, 2005)

Yes this is the El Natural forum. The advice I gave is based off NPT theories. No bacterial filtration.
Falling Ph is caused by lack of CO2. I would guess your filter may be a HOB (Hang On Back), like a biowheel type. Causing surface disturbance, thus releasing what CO2 you may have. This will also affect your Kh because your CO2 is dissipating.

Do a search in this forum for CO2, agitation, disturbance. This should yield some results to help you minimize surface disturbance.

I tried all sorts of things to stabilize my Ph. I finally bought some crushed coral and seem to be doing good now.

Good Luck!


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## dwalstad (Apr 14, 2006)

peridot said:


> Hello
> I am running a nice Nano (12gal) El Natural and I have some mechanical filtration to keep the water looking pretty. Plants and fish are well but increasing amount of thread algae (cladophora?) The filter is just filter fabric sewn up into sock shape thru which water water is pumped. In the tank, pH has recently been rountinely going down and now I find that the nitrates are up to 18 ppm, so I suspect that the filter is hosting nitrifying bacteria. Normally I just rinse it out now and again. But to kill nitrifiers I think I might steam it in the microwave and rinse it again. If I use bleach, I have to worry about getting it all out again.....
> 
> What do you think?
> ...


If the pH is consistently falling, that means that plant growth (pH goes up via photosynthesis) is less than nitrification (pH goes down) and fish load. See my book, p. 5.

Rather than trying to kill nitrifying bacteria, I would try to encourage better plant growth. Better plant growth will bring the pH up and reduce nitrates. It does no good to kill nitrifying bacteria in the filter if your entire ecosystem encourages their activity. You may kill nitrifying bacteria in the filter, but there are many, many more nitrifying bacteria on plants, glass, and gravel layer.

You may need to add more lighting, faster growing plant species, etc to increase total photosynthesis in your tank.

You need to balance fish load with photosynthesis.


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## peridot (Feb 24, 2005)

Thank you Ms Walstad! I think the fog is clearing. I will turn my focus to boosting photosynthesis.

-Not including tails I have about 9 inches of fish in 12 gallon tank and they are on the mellow to moderately active side so hopefully I have not overloaded the tank. 
-I may have been over-generous feeding the fish/plants.
-Nitrates were higher than the 17 that I previously posted as I had done a water change maybe a week before; guesstimate 25 mg/l. (water change was not routine; corrected an error I made restoring total hardness)
-Tank is a JRC Nano so the filter is a home-made cloth sock whose mouth hangs open where the foam block would be. It could easily be that it does not have enough surface area to support a significant biological filter.
-Circulation is one submerged pump, no splashing or biowheel.
-There are both rooted plants (including one vigorous weedy one) and duckweed.


To remedy pH, algae and nitrate problems I have done a water change, added a little baking soda, increased lighting to 15 hours, added water sprite to floating plants. I will check how old my bulb is. I will continue to maintain total hardness around 140 mg/l. The total hardness goes down so fast I am wondering about adding shells just to put a floor under it. I do live on the ocean (in Maine). You may not want to ask me about my water source! I am the one who has whole house reverse osmosis as a water source so I have to build my water back up. (usually Seachem Equilibrium) Our well has salt water in it and our taps have RO with a little (10 mg/l) calcium in it.

This is not a new tank. In fact it is 5 years old. It was quite stable until about a year ago until our well went salty and we had to put in the RO system. Interesting.....

Many thanks indeed

Peridot


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## rohape (Feb 7, 2005)

How much light do you have now? Depending on how much you have you may want to look at _adding_ light, not extending. Your algae problems will more than likely get worse by extending the photoperiod.
I would definitely look at adding shells.



dwalstad said:


> You may need to add more lighting, faster growing plant species, etc to increase total photosynthesis in your tank.


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## will5 (Oct 26, 2005)

peridot said:


> Isn't this the El natural forum!?
> 
> Ms Walstad, can you help us? Persistently falling pH is the trouble I am trying to fix. If reducing my population of nitrifying bacteria helped calm down the algae that's good too.
> 
> ...


Yes sorry I see That now.[smilie=l:


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## peridot (Feb 24, 2005)

I have a 24 watt bulb. The tank is constructed with a partition such that the rear portion is walled off and recieves no light so I would say that that light reached 10 to 11 gallons. I figure 2.5 watts per gallon. I lengthened the duration because in a discussion elsewhere in this forum, Ms Walstad (I think?) recommended it as a way of boosting our favored plants in their effort to out-compete the algae. 

I am not trying to get nitrates down to zero. 25 mg/l seems a suspiciously high given persistantly falling pH. 

(I should also add that I have a small UV running in case that's relevant somehow)

But who knows ....?......


Peridot


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## jusu (May 22, 2008)

peridot said:


> I have a 24 watt bulb.


What kind of a bulb? Is it fluorescent? What is your fish stock? How densely planted?


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## peridot (Feb 24, 2005)

Lighting is 24 watt fluorescent 6500k. Earlier I think I called the tank manufacturer JRC, that's wrong, it's JBJ. JRC is stereos, right? Rooted plants grow moderately and are of moderate density, floaters grow like mad and risk shading rooted plants out if I don't thin them regularly. Fish are quite happy so long as I keep the pH from dropping too far. When the corydoras stop dancing around I know I have been lazy about check pH.


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## rohape (Feb 7, 2005)

Fish can adjust to Ph changes as long as it isn't sudden. My Ph has gone from 8.0 down to 6.0 and is now at about 7.2. All within about 1 year time frame. (Don't ask, was having similar issues controlling Ph  ) Every single fish came out of it just fine. So I wouldn't be too concerned with your Ph, as long as it's not crashing. Since you've done a water change and made some changes, try riding it out. Let the tank settle down some and see what happens. Sometimes you can do more damage by trying too many things chasing problems. Give it a week, maybe two. Keep an eye on things just to make sure they don't destroy your tank.


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## helgymatt (Sep 12, 2007)

What does your pH fall to and where does it start?


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## dwalstad (Apr 14, 2006)

peridot said:


> This is not a new tank. In fact it is 5 years old. It was quite stable until about a year ago until our well went salty and we had to put in the RO system. Interesting....
> 
> Peridot


Yes, very interesting! 

Here's my take: Your water is soft and not buffered as well as before. Equilibrium, unfortunately, has too many sulfates for NPTs (it works fine for tanks without soil). Instead, I would use the "Calcium Dosing Procedure" described in the El Natural "Stickie" for Useful NPT Links. The Calcium Dosing Procedure uses calcium chloride instead of calcium sulfate to bring up water hardness. Sulfate-rich fertilizers are not good for NPTs. A little sulfate is okay, but Equilibrium is made up almost entirely of sulfate fertilizers.

Your tank's ecosystem has changed entirely due to the new water regimen. Plants may not be growing as well OR denitrification (which consumes nitrates and brings pH up) in the substrate may have slowed. The inhibition of denitrifying bacteria could be due to the excess sulfates that you are pouring into the tank every time you use Equilibrium.

I would do water changes and use a little baking soda for now. Consider mixing your hard well water with the RO water instead of dosing tank with Equilibrium. If this doesn't work, I would follow the "Calcium Dosing Procedure" for increasing water hardness.

Intriguing question, Peridot.


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## peridot (Feb 24, 2005)

I was wondering in my mind about whether to use Equilibirum or Calcium chloride and magnesium sulfate. Thank you so much for helping me sort that out. I am quite familiar with your calcium dosing procedure although I have often wondered how long to wait for proper mixing before testing again Not sure I can use my untreated well water at all. Depending on the tide, it has varying amounts of sodium chloride in it (!) . I live right on the ocean, you see. Any idea how much chloride is OK for freshwater fish. Have a Hach kit for chloride from when the well went bad. Must say, it 
has been most helpful to have Hach's test kit for both Total and Calcium hardness. I wonder if I need to get a grip on other nutrients like potassium that would normally be in proper well water?

Right now I am running a little 12 gal tank. As I have in the past, in other locations, I hope go back to having a larger tank but I certainly need to figure out how to manage with RO as my water supply.

Peridot


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## dwalstad (Apr 14, 2006)

peridot said:


> I was wondering in my mind about whether to use Equilibirum or Calcium chloride and magnesium sulfate. Thank you so much for helping me sort that out. I am quite familiar with your calcium dosing procedure although I have often wondered how long to wait for proper mixing before testing again.
> 
> Peridot


I don't understand this part. Calcium chloride and magnesium sulfate dissolve instantly so its just a question of waiting until the solutions mix in your aquarium before taking the GH water hardness measurements.

Note: this doesn't have to be perfect. As long as you add more calcium than magnesium and get the GH up to 8 or more, you'll be fine.

As to the K (potassium). This is an important nutrient and a little scarce in fishfood (my book, p. 80). Therefore, it wouldn't hurt to add some K to your "cocktail". As I describe on p. 87 of my book, you can use "Salt Substitute", which is mainly potassium chloride (KCl) at about 1/8 teaspoon per 10 gal.

If your well water is mainly marine saltwater, then you're right not to use it. There's just too much NaCl.

Calcium dosing makes keeping NPTs a little more complicated. Hopefully, once you've done the original calcium dosing, you'll only need to add the cocktail if your GH decreases substantially or for major water changes.

I don't have softwater, so others may be able to help you out with their experiences.


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