All about Denitrator

Originally Posted by WaterZoo

Bro Atom ... you're absolutely correct by commenting that sulphur based denitrator is meant for marine environment and not suitable for any freshwater tanks.

Bro, can you elaborate on why the sulphur beads denitrator is not suitable for freshwater tank?

Thanks.

does it mean orp will read significantly lower comparing nitrate levels of abv 100ppm and that of below 25ppm? what would be the ideal orp for comm tanks?

Originally Posted by carlfsk

Bro, can you elaborate on why the sulphur beads denitrator is not suitable for freshwater tank?

Thanks.

Actually it is the by product of the sulphur beads that is not suitable for freshwaer tank because of toxicity.

Sulfates are harmless to fish, is odorless and quite stable. By contrast, in sulfides, such as hydron sulfide (H2S), the sulfur atom is reduced, stripped of its oxygen and joined to another atom. In short, sulfides are reactive and they can be very toxic.

Hydrogen Sulfide has been a hooha to aquarists, who have sniffed their tanks for the tell-tale whiff of rotten eggs that would confirm their dark fears which could leads to disaster.

Howver, to get the H2S up into the main tank, it takes a long time depending on the tank volume capacit.

This is my understand and others may have a different view.

Pls comment.

Originally Posted by MilkMan

does it mean orp will read significantly lower comparing nitrate levels of abv 100ppm and that of below 25ppm? what would be the ideal orp for comm tanks?

Not really. Try reading through this link as it will give you an overall picture of ORP.

http://canadiankoiandpond.ca/articles/article13.html


The ORP which I am introducing is lean towards denitrification than the general condition of an aquarium.

Btw, warning to those who are feeding to reduce nitrates. I got a chinese rice wine of 20%. Tuesday night ibs, poured the remaining 100ml or so into the tank and slept. Coz i lazy to feed the denitrator, and thought of testing if i can seed my dsb.

Results disastrous. Yesterday night i return to find my whole tank super cloudy to the extend it's like 1 glass 1/2 milk 1/2 water. Further inspection it's slime. Bro atom, can enlighten me what could the bb be? aerobic?

Had to straight away do 75% w/c and till today still cloudy. Still got a sample of the water if anyone wants.

Originally Posted by atom

ORP - What does it do and how does one benefit from it.

Denitrification is as natural as nitrification. It depends on the level of (in our case) dissolved oxygen present within the water column itself. For the case of a denitrator, very low level or no dissolved oxygen must be achieve for it to work.

What is ORP? It stands for Oxidation Reduction Potential and the measuring unit is denoted as mV. Sometimes it is also known as pollution index. In our case, it is the measure of the relative oxidizing power of the water. Sounds simple? It is, perhaps, the single most complicated chemical feature that aquarists will typically encounter! I will try to explain as simply as possible and how it can be applied on the denitrator.

In our aquarium, just imagine it is a battlefield comprises of oxidizers and reducers. ORP is the measurement of who is winning and who is losing. We cannot have only either one of them as the livestock will be very very dead.

The majority of oxidisers are O2 and the minorities are O3 (ozone), H2O2 (hydrogen peroxide), 3O2 (triplet oxygen) and other variety of oxygen radicals with also include chlorine and chloramine. The oxidisers need to get electrons and they get them from the reducers.

The reducers are: inorganic compounds such as ammonia, iodide and sulfide. Vitamins C is a very powerful reducing agent.
The reducers come from fish food, metabolic waste products, the breakdown of dead organisms, and certain additives put into the aquarium. The reducers all want to get rid of electrons, and they virtually throw them at the oxidizers.

To be continue.....

In summary, the ORP is a measure of the relative fighting ability of the oxidizers and the reducers. In other words, it is the measure of electrons "pulling and pushing" from a solution. If you add oxidizers to the aquarium (aeration, ozone, permanganate, hydrogen peroxide, etc.) then the ORP rises. Alternatively, if you add a lot of organic molecules to the solution, or restrict the oxygen supply, the ORP drops.

Inside the denitrator, low oxygen or anoxic or anaerobic process is fundemental for dentrification. Since this is the case, using a DO meter should be the most appropriate. Not really. The problem of using DO control in an anoxic or anaerobic process is that DO readings become unreliable when DO is below 0.1 to 0.2 mg/L (Moriyama et al., 1993).
This is where ORP comes in as it is an indirect measurement of DO (dissolved oxygen) at concentrations that can not be measured directly with DO probes.

Here is a report on the effect of oxidation-reduction potential on biological denitrification.

http://seminar.dicer.org/seminar/ppt/550.pdf

Originally Posted by Lonerboi

Btw, warning to those who are feeding to reduce nitrates. I got a chinese rice wine of 20%. Tuesday night ibs, poured the remaining 100ml or so into the tank and slept. Coz i lazy to feed the denitrator, and thought of testing if i can seed my dsb.

Results disastrous. Yesterday night i return to find my whole tank super cloudy to the extend it's like 1 glass 1/2 milk 1/2 water. Further inspection it's slime. Bro atom, can enlighten me what could the bb be? aerobic?

Had to straight away do 75% w/c and till today still cloudy. Still got a sample of the water if anyone wants.

Too much alcohol ....too much carbon source leads to sudden increase in anaerobe. Same as bbs bloom. Try not to use chinese wine. Use diluted volka.

Originally Posted by atom

Too much alcohol ....too much carbon source leads to sudden increase in anaerobe. Same as bbs bloom. Try not to use chinese wine. Use diluted volka.

haha... liddat i should bottle my water and sell to jump start the denitrators. Hmm, any reason why chinese wine is not gd?

Originally Posted by Lonerboi

haha... liddat i should bottle my water and sell to jump start the denitrators. Hmm, any reason why chinese wine is not gd?

Tried on octane's denitrator...it give lots of false reading. It might be the ingredient used.

There are many dissatisfied users of denitrator for both freshwater n marine keepers. Here are some of the reason:

- difficult to operate
- it take years to mature
- very difficult to control the output flowrate
- never really keeps the nitrate in control
- too tedious
- very unstable result

As discussed previously, the anaerobe will begin denitrification when the condition permit, namely:
- low or 0 Oxygen level
- the availability of carbon source
- the nitrate level

There are also other factors that will affect the rate of denitrification like pH and temperature.

Although there are so many negatives on operating the denitrator, by adjusting the flowrate will solve most of the problems.

Since ORP is the measure of electrons pulling and pushing in a solution or the measure of the relative oxidizing power of the water, it is ideal device to measure the condition inside the denitrator. The condition should be mainly reducing than oxidising. This makes the ORP a more suitable measuring device than the DO meter which is very inaccurate at very low level of dissolved oxygen.

By incorporating an ORP, the condition inside the reactor can be measured and thus the flowrate can be adjusted accordingly. This is done by using an ORP controller and not ORP meter. ORP meter provides only the reading whereas ORP controller provides an additional on/off power supply to operate the device that is responsible for the flow. With this device, no tedious n frequent meddling on the flowrate anymore. Just let the ORP controller monitor and control!