Finally achieved 0 nitrates

[Rocksor]

So with my specific tap water chemistry, a 50ppm increase in TDS generally means orange/red API nitrate test, above 20ppm, so an increase of at least 25-30ppm. Ive checked this for a few months between a TDS meter and API nitrate test. The real kicker is that over the course of the year, my tap water TDS fluctuate between 385ppm - 485ppm.

so did you measure your tap water TDS each time prior to a water change?

 

[DDK]

Low to no maintenance fish keeping us the holy grail !
I suspect bio film is reducing your nitrate as much or more than denitrification.

I suggest you look at constant drip auto water change to lower your maintenance further as getting low nitrate will not mean no more water changes. Like you, I have many fish tanks - some very large. I have several fish rooms in fact.

Ah i see you noticed one of the oldest tricks haha. I do purposely not clean the bottom/back of the tank to keep the algae there in hopes of it lowering nitrates.

So when you say you use a tds meter to determine 0ppm nitrates, what is your tap water tds and your tank tds?

My cities water ppm is 190ppm during the day and at night 200ppm as less people use water so it does sit and pick up crap from the pipes in the street.

city water
190-200ppm
Tank water
210-220ppm

I do 90% changes because i do top off with tap water for evaporation

 

[esoxlucius]

To seal the deal for me it would have been nice, just for this experiment, for you to have several before experiment and after experiment nitrate readings along with pictures of test vials against the colour chart......using an actual nitrate test kit. That's the currency of nitrate testing we're used to.

It would have looked really good for your experiment if your before readings of 80ppm, showing a horrible deep red on your chart, were to have miraculously changed to the beautiful bright yellow of 0ppm, which is what you are claiming.

 

[duanes]

The problem using a TDS meter to get an accurate nitrate reading, is that TDS is a combination of all organic and inorganic salts in the water.
These include, and are not limited to, carbonate, bicarbonate, calcium, phosphate, sodium, potassium, nitrate etc etc
So the idea that a TDS meter will differentiate only nitrate is not possible.
If you want to measure just nitrate, you must use a nitrate test, with the proper reagents that differentiate the nitrate species .
If you want to measure phosphate levels you use a specific set of reagents to measure phosphate.
As generic (inaccurate) as the API nitrate test is, it is the only way to separate nitrate, from all the other components a TDS meter detects.
Sure, when I was a chemist at a water facility I used a very accurate spectrophotometer to get separate nitrate readings down to the 100th place required by EPA guidelines, but now retired, I find the API (and a few other brands, and even strips) adequate enough for generic aquarium use.

 

[twentyleagues]

I agree with duanes and others that without a traditional nitrate test I can't believe 0 nitrate. It's possible that the biohome being so compact is removing some other tds instead of nitrate, idk and neither do you without a test. I do think/believe in the idea of anoxic filtration removing nitrate. I use it and know it works to a point. I also know biohome can create or should I say support anoxic bacteria as can matrix if used properly. The surface area for that size tank would need to be very large to reduce nitrate from 80 to 0. Time frame is also a problem for me. Nitrate reducing bacteria isn't easily cultivated in fresh water fish tanks. For reasons not completely know or should I say understood by myself it's much easier to grow in saltwater, maybe from preexisting colonies with in live rock......? I have been messing around with this pretty hardcore for the last 3-4 years. Currently trying biocenosis baskets as a experiment. Unfortunately I've not been keeping it really scientific.
So overall I doubt the title and claim of 0 nitrate without a proper nitrate test. But hope it's actually true....

 

[Rocksor]

I've been running biohome (with other ceramic media) in my 3 canisters for years. I've never witnessed nitrate reduction or lower TDS. Maybe it's because I open up the canisters regularly for maintenance. I've got them on a 10 week cycle of cleaning, and they aren't slimy enough to slow down flow on my canisters.

 

[duanes]

The only way to use a generic TDS test to find nitrate, would be to have a complete assay of every component of the water, every chemical species, and examining all percentages of each separate species component (ie 25% cal, 35% sodium 18% iron, 2% nitrate etc etc) and then determine what each of those percentages are in ppm.

 

[DDK]

Alright guys haha I get you guys would like a nitrate test kit but I'm not going to spend the ten bucks when I have my method that works for me, just because it works for me doesnt mean its going to work for you. I can do 90% w/c's and my jardini will lay on its side and chill there calmly so I can pull 90% of the water, some peoples fish would freak out and hurt themselves, mine doesnt. I feed 2-3 times a week, many others feed daily, as I said what works for me might not work for you. My method of using tds to calculate nitrates work for me and might not work for you.

No one is saying I am finding the exact level of nitrates in the water nor does the api nitrate test kit hold any merit to me as its just matching vague colors. I know the ppm of the water I add to the tank 190-200ppm, and have done 90% water changes as a habit to prevent minerals from building up from evaporation and to knock down nitrates as low as I can cause im lazy and do water changes once a month. Any reasonable tds increase would have to be nitrates unless the tank evaporates a substantial amount of volume and concentrates the dissolved solids in the water. But even then, I know I add 20 gallons in-between water changes and finding the % is basic quick math. Nothing in a fish tank other than nitrates will increase the tds value unless its evaporation is concentrating the dissolved solids in the water, but I can easily calculate it.

Tanks volume: 240 gallons
Evaporation loss: ~20 gallons
Time frame: Every three weeks
City water ppm: 190-200ppm

volume of water replenished due to evaporation
20g of 240g = 8.33%
concentration of tds in 240 gallons = +/-200ppm atm 4/29
8.33% (volume of 20g) of 200ppm = +16.66 ppm
In theory the water that has evaporated (20g) would raise the ppm, 16.66ppm leading to 216.66ppm, before I add 20 more gallons of water at 200ppm bringing the ppm down the final ppm, to 208.33ppm. From here I can have a general idea of how much nitrates have built up nor how much dissolved solids have built up from evaporation.

Then at 90% water changes I can do quick math to find the general range of ppm accounting 8.33% of evaporation
90% of 240 = 24 gallons
concentration: Now 208.33ppm including topping off 20 gallons
10% of left over tank water: 208.33ppm at 24 gallons of water
adding 90% of 200ppm city water: 200.833ppm

So yea a nitrate test kit would give me a vague idea, but I also can do the quick math to calculate the build up of nitrates versus tds increasing from evaporation and also have a vauge idea as evaporation is the constant. Subtracting the concentrating dissolved solids due to evaporation and also me topping off the tank is basic math I can do in my head in 10 seconds which gives me a ball park figure of nitrates, I dont need to spend 10 dollars on a nitrate test kit when I can think for 10 seconds and probably have a better idea of nitrates than most do distinguishing different colors. But as I said, do what works for you.

Heres the tds for 4/29


Water level is at the same level, tbh I was a bit surprised it did go down from yesterday as I actually fed yesterday. These are just my results and from my logic I'm determining denitrifying bacteria are doing their job. You are free to think other wise and I wont stop you nor try to change your mind.

 

[DDK]

So with my specific tap water chemistry, a 50ppm increase in TDS generally means orange/red API nitrate test, above 20ppm, so an increase of at least 25-30ppm. Ive checked this for a few months between a TDS meter and API nitrate test. The real kicker is that over the course of the year, my tap water TDS fluctuate between 385ppm - 485ppm.

so did you measure your tap water TDS each time prior to a water change?

Thankfully my city water is snow melt, and stays constant