119 replies to this topic

[Cawdor]

I'm looking into ways of reducing nitrates without having to change the water or using plants. I have come across an excellent article on nitrates in general and ways of reducing them. Thought I'd share this:

http://joejaworski.w...11/12/nitrates/

http://joejaworski.w...ow-up-nitrates/

I wasn't sure if this should go into the article section or not, mods feel free to move this.
Has anyone used the sulfur method or the aquamedic? Would be interested in experiences with these.

[jack]

Tim i have a aqua-medic nitratereductor 400. iv found in a overstocked tank it will keep nitrates low if they are low to start with . when i put mine on nitrates were 30, lowest its been with nitratereductor is about 25 but saying that if i wanted to get it down further you can add more denimar tablets to help the biological filter it recommends to feed quite often to start with on an already well established tank until the slimy bacterial biomass is formed.

jack

[Cawdor]

Thanks Jack. I've been reading up on this and it looks like a good unit, once it is set up correctly and the flow rate is adjusted it should work quite efficiently. How long did you have yours for and how long did the initial period last for until it was working 100%?
I'm looking at reducing my waterchanges for one of my tanks to maybe once every 4-6 weeks or so rather than weekly. It's just getting a bit much, takes me all afternoon to do all the tanks properly.

[jack]

How long did you have yours for and how long did the initial period last for until it was working 100%

it took about a month to become fully snotted iv had it now for about7-8 weeks i think

[Krystal]

I currently have the Aquamedic 400 nitrate reductor but it has only been a week so no results as yet but the 8'x30" at Aquotix has had theirs running for around 2 months now and the nitrates have come down to 15ppm-20ppm MAX! and those are some large garbage disposal units swimming around in there. They are excellent units and look forward to the rewards from mine. Aquamedic says it takes up to 8-10 weeks, for a heavily stocked tank, for the nitrate reductor to start working at its optimum

First hand, they work great!

[Cawdor]

Cheers Krissy, was gonna come into the shop today but it's closed! Damn.
I think I will purchase a unit and see how it goes on my 6x2x18. It's the hardest to change the water cause I have to use a pump (it's too close to the floor to get the physics working for me).

[Brett]

Tim's post raises the question of whether there is any substitute for water changes. Sure, there are other methods of reducing nitrates, but is this the whole story? What about all the other waste products produced by our fish that we can't measure? We know that some of these are biologically active. How do these chemicals get remove from the system?

Personally I see high nitrates as an indication that the system is not coping with the bio-load, and the only effective strategy is water changes.

Cheers

Brett

[Neakit]

brett just a thought but tap water has nitrates in it to start off with.

[Cawdor]

Personally I see high nitrates as an indication that the system is not coping with the bio-load, and the only effective strategy is water changes.

Brett, I wouldn't say that high nitrates are an indicator of the system not coping. Nitrate will accumulate as it's a waste product that, unless your tank is heavily planted, is not broken down. So every tank will eventually have high nitrates, UNLESS you change the water or use a nitrate reductor. I would agree that if, for example, you do weekly waterchanges and your nitrates are still high, it's a sign that there is a lot of waste being produced in your tank. It's also a sign that your system is working and breaking down ammonia and nitrite! So in that respect it's a good indicator.

With this nitrate reductor I'm not looking at replacing waterchanges. I simply want to reduce the frequency of my waterchanges. I was also told that this particular unit can also provide an environment for bacteria that brake down other byproducts, so its use is not limited to just nitrate. I will provide some feedback on this unit after it's been running a couple of months.

[sydad]

I was also told that this particular unit can also provide an environment for bacteria that brake down other byproducts, so its use is not limited to just nitrate. I will provide some feedback on this unit after it's been running a couple of months.

Hi Cawdor,

While not saying that the facultative anaerobes , that are relied on to reduce nitrates, will not break down other "byproducts" of fish metabolism, I will say that they tend to produce more of their own as a result of the metabolic changes engendered in the switch from aerobic to anaerobic function . Bear in mind that bacteria that are normally aerobes, or at best microaerophilic, require additional dissolved organic carbon sources to be added to the aquarium if they are to function as promised by the manufacturers of denitrating systems. It is quite difficult to adequately determine the optimum requirements of these organisms, and as a result you can either effectively further pollute the aquarium, or just wind up with another useless "system" within the aquarium.

I played around with bio-denitrators for several years before deciding that a reasonably deep substrate layer performed the funtionality I desired without introducing the complications necessary to ensure their efficient functioning.

If you decide to use the unit, and "provide feedback", please ensure that you mention any inexplicable events that occur during the use of the unit.

Cheers, Syd.

[Cawdor]

Bear in mind that bacteria that are normally aerobes, or at best microaerophilic, require additional dissolved organic carbon sources to be added to the aquarium if they are to function as promised by the manufacturers of denitrating systems.

This is taken care of by special balls that reside within the unit and brake down over time, providing the carbon sources for the bacteria. There are also additional tablets that can be dissolved in water and fed into the system if required. The manufacturer has actually included information about how it works as well as some basic chemistry information in the manual, which was a positive surprise. usually you just get "this is how you assemble it and this is how you clean it" in the manual.

If you decide to use the unit, and "provide feedback", please ensure that you mention any inexplicable events that occur during the use of the unit.

I plan on doing that. The tank that the unit is connected to is very stable and "predictable", so any unusual readings or occurences will be noted.

[Cawdor]

Ok I've had the unit running for a week and after a few days I could see the slime forming already (even though I had it running according to Oliver's suggestion and having full water flow, not drops), now it has increased and I can see lots of bubbles in the unit which tells me the bacteria are hard at work. Yesterday I turned down the flow rate to 2 drops per second.
Coincidentally I tested my nitrates today and they were at 20ppm, usually after 2 weeks after a waterchange I have about 40ppm in that tank. I want to believe it's already making a difference but it's probably just coincidence.

Fish are happy and breeding, so it's no difference to their well-being.

[Cawdor]

It has been about 5 weeks now. They say it takes 6-8 weeks to take full effect, but I'm already seeing changes. Normal nitrates in this tank after a waterchange are around 20ppm. I used to change the water weekly or fortnightly if I had no time. By the time I did the change the levels are usually around 40-50ppm. These are still the levels I get (just under 40ppm), however I can now leave the tank for about 3 weeks without a waterchange. Exactly what I want - less time consuming maintenance. The only maintenance I do now every day is to check the flow from the nitrate reductor, I try and keep it to around 2 drops per second.
Maintenance on the unit itself is non-existant - there's nothing to do except let it run. Once the white balls are used up, which I'm told can be anywhere from within a year to about 2 years, it's simply a matter of placing new white balls in there.

Some photos:

Water inflow control: Eheim pump connected to the t-junction (supplied with the unit) and a valve at the end to control pressure. Nothing fancy but it works.



The outlet: drops and gas are expelled here. Drops are easy to see and count.



Main unit: the white balls are the food for the bacteria, the black ones just provide surface area to grow.



Close-up: slimy goodness. The more the better! Also visible are the bubbles of gas.

[Krystal]

WOW, and i thought my nitrate reductor was slimy! Mine has got about half of that anerobic slime in it.................mind you theres only one fish in the tank

Glad you are happy with the outcome Tim, they are definately worth the investment.
And as you stated, they are not a replacement for water changes but just a tool to keep your nitrates at an acceptable level in between cleans or to give you just a couple more weeks in between water changes.

[dazzabozza]

Looking good Tim

How much did it cost u to set up? Ongoing costs?


Dazza

[Cawdor]

Dazza, the Aquamedic cost me around $220, can't remember the exact cost. It comes with everything. The T-junction is supposed to run off a canister hose, so if you don't have one or an unsuitable one like me, then you gotta run it off a small pump. Overseas the unit retails for around 80 Euro ($129 bucks) so there is a significant increase in price.

Ongoing costs are just electricity and once the white balls are used up, you gotta replace them. I read they last anywhere from 1 year to 2 years. I haven't looked into replacement costs for these, they are called "Deni Balls" if you wanna google them.

[slink]

What will happen if the white balls are past the used by date as to speak and they don't get changed will all that nitrate go back into the tank. Sounds like external cannister filters when they are not maintained correctly and the nitrate gets pushed back into the tank. Any idea how it stops this????

[Cawdor]

What will happen if the white balls are past the used by date as to speak and they don't get changed will all that nitrate go back into the tank.

You misunderstand how the whole thing works. Nitrates are not trapped in there, they are broken down by bacteria who use the oxygen molecule in nitrate for their metabolism. The white balls act as a food source and diminish over time. If a situation arises where the white balls are completely gone and you do nothing about it and just let it run, the bacteria would die off and it would just be another waterpump connected to your tank. No negative effects at all.

[slink]

It's hard to believe with that process you can brake down all of the nitrate going through that system. there is always something that can go wrong and it's still connected to the tank. what ever happened to the good old water changes.

[Brett]

I would like to thank Tim for his interesting post. It's heartening to see people critically analysing their management techniques.

However, from my perspective, the most important information has been omitted. That is the health and growth of the fish.

The impression this post gives, and I am not blaming Tim for this, is that if you lower nitrates sufficiently you can reduce or even cease water changes without reducing the health of your fish. I am not convinced this is the case. Nitrates are products of metabolism, that we can measure. So there is a tendency to rely on them and not consider the many other products of metabolism that we can't measure (or see).

In my previous post I said, "high nitrates are an indication that the system is not coping", this was misinterpreted by some, who thought I meant the filter was not coping. What I meant was the system, that waste products were building up faster than they were being removed. The vast majority of us keep systems that don't cope with the bioload, we forget that this is not the norm. In a bigger system, with a lower bioload, the waste would be broken down as quickly as it was produced, there would be NO build up of nitrates.

I guess this is just a long winded way of saying I think you should concentrate on water changes and not nitrate reduction. If you are going to buy extra equipment, it is my belief that your money would be better spent on a more efficient water changing system.

Cheers
Brett