• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up
  • You can now follow UKAPS on Instagram.

Nitrate Tests?

tdc999

New Member
Joined
19 Nov 2020
Messages
22
Location
Germany
Hi

I have a 240L planted tank.

I would describe the planting as medium to high.

I think for the size of the tank the fish stock is low.

I have CO 2.

An external Oase 850 filter.

The tank has been running for almost 1 year.

I have been testing the water with the API freshwater test kit.

Apart from the Nitrate all the other tests are very good.

Over the past couple of months the Nitrate has been going steadily upwards 80+

I have been doing water changes of 25% twice a week.

The filters are are closely monitored .



After all this the Nitrate does not improve.



I now have Pro JBL Aqua test.

The Nitrate reading is between 15 and 30.

Clearly this is a huge difference.

Point is which do I go with.



The fish appear happy enough. I would have expected some to be killed off at the higher reading.

Hope someone can pass on some ideas.



Just to add the API has an expiry in 2005.
 

Nick potts

Member
Joined
25 Sep 2014
Messages
953
Location
Torbay
I have been testing the water with the API freshwater test kit.

Apart from the Nitrate all the other tests are very good.

Over the past couple of months the Nitrate has been going steadily upwards 80+

I now have Pro JBL Aqua test.

The Nitrate reading is between 15 and 30.

Clearly this is a huge difference.

Point is which do I go with.



The fish appear happy enough. I would have expected some to be killed off at the higher reading.

Just to add the API has an expiry in 2005.

Go with neither, testing nitrates with hobby grade kits is difficult, and as you have found not at all reliable. Having said that a test kit that is 16 years out of date no matter is not going to be any good.

You say the fish seem healthy, how about your plants, the best way to judge a healthy tank is always going to start with just observing the general health with your eyes.

If I had to go with one it would be the lower number, in a CO2 injected tank with a good plant mass nitrates should be being used up pretty well by the plants.
 

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
Messages
13,818
Location
nr Bath
Hi all,
The fish appear happy enough........
I would describe the planting as medium to high. I think for the size of the tank the fish stock is low.
As @Nick potts says that is the only bit that really counts. You have healthy fish and plenty of plants, it is very likely that you have low NO3 levels, and even if you don't it doesn't really matter.
I have been testing the water with the API freshwater test kit.
Apart from the Nitrate all the other tests are very good.
Over the past couple of months the Nitrate has been going steadily upwards 80+
I have been doing water changes of 25% twice a week.
I now have Pro JBL Aqua test.
The Nitrate reading is between 15 and 30.
Clearly this is a huge difference.
Point is which do I go with.
You probably have somewhere between 15 and 30 ppm NO3. I say "probably" because nitrate testing is <"not entirely straight forward">.

It was partially the difficulty with getting accurate values for nitrate (NO3-) that led me to the <"Duckweed Index"> a technique where you use the health and leaf colour of a floating plant to <"estimate fixed nitrogen availability">.

cheers Darrel
 

tdc999

New Member
Thread starter
Joined
19 Nov 2020
Messages
22
Location
Germany
Thanks for the replies.
Slight error with the expiry date. Should read 2025!
The plants are doing well.
I may take some water to our local aquatic shop and get it rested. Can't do any harm.
Thanks again.
 

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
Messages
13,818
Location
nr Bath
Hi all,
I may take some water to our local aquatic shop and get it tested. Can't do any harm.
It really depends what analytical equipment they have. Can you get figures from your water company? The EU limit is 50 ppm NO3 in drinking water and the water company will have a proper analytical lab. and scientists etc.

If the aquatic store have an <"ion selective electrode"> (and <"some-one who understands how to use it">) they should be able to get a ball park figure. If it is a <"semi-quantitative titrimetric test">, where you can construct a standard curve, it will probably be similarily accurate, but after that their guess will be as good as yours.

cheers Darrel
 
Last edited:

MichaelJ

Member
Joined
9 Feb 2021
Messages
1,690
Location
Minnesota, USA
Hi @tdc999 What are you dosing for fertilizer? and what's the NO3 level in your WC (Tap) water?


I am dosing 20ppm of NO3 per week and my WC water is (40% Tap / 60% RO) is around 1.5ppm (Our tap water is around 3-4 ppm). When I measure my tank with my API kit I get this - picture below (this is from a healthy and clean tank with seemingly happy shrimps and fish). Not only is it hard to measure NO3 with a test kit such as this, but even the scale your matching the test solution up against is very hard to gauge - Is this measurement supposed to be 40 or 80ppm or perhaps more?!... As mentioned above, as long as livestock and plants are healthy - and have a good reason to be healthy due to proper maintenance (regular large WC's etc.) I wouldn't worry about it.

PO4NO3.jpg



In addition to the Duckweed Index a good way to monitor overall tank health is to gauge the TDS level over time - if you have gradually rising TDS, due to buildup of waste etc., it's a good indication that maintenance might be insufficient. Besides temperature, it's pretty much the only thing I measure on a regular basis these days.

Cheers,
Michael
 
Last edited:

tdc999

New Member
Thread starter
Joined
19 Nov 2020
Messages
22
Location
Germany
Thanks for the info.
I am using home made ferts. the recipe is taken from the Barr Report. The plants are doing very well. May get some algae on the leaves but not enough
to cause any issues?

Whilst I was looking at articles regarding water chemistry I came across

Measury PH Meter Aquarium + TDS Meter Set, Conductivity Meter Aquarium, PH Tester Pool and Water, pH Meter, PH Value Meter.​

This is just one of many i found.
Has anyone got experience with this type of meter.
 

Nick potts

Member
Joined
25 Sep 2014
Messages
953
Location
Torbay
Thanks for the info.
I am using home made ferts. the recipe is taken from the Barr Report. The plants are doing very well. May get some algae on the leaves but not enough
to cause any issues?

Whilst I was looking at articles regarding water chemistry I came across

Measury PH Meter Aquarium + TDS Meter Set, Conductivity Meter Aquarium, PH Tester Pool and Water, pH Meter, PH Value Meter.​

This is just one of many i found.
Has anyone got experience with this type of meter.

I can't see a link, but I am guessing it is a cheapish set from amazon or similar?

I use a cheap TDS meter and a PH probe, they work fine but like any measurement device, it needs to be calibrated and looked after and used properly to be of value.
 

erwin123

Member
Joined
4 Mar 2021
Messages
849
Location
Singapore
Amazon product

I got the Apera PH20 for under US$50 from amazon including shipping. It has 4401 ratings and 119 Q&As on its amazon product page so it appears to be a popular product. When I calibrate it with 4.0/7.0 solution I find that after 1 month of use ,it is just 0.1 away from the reference.

Apera PH60 + 1 cost of 1 replacement probe costs 3x the price of PH20. So instead of buying a PH60 and replacing the probe, I could just buy 3 PH20 at the same price.

If I have the opportunity to compare it with a more expensive ph tester I'll do so and report the results
 

Kelvin12

Member
Joined
16 Nov 2020
Messages
170
Location
NSW Australia
As luck would have it I was just about to post a question about TDS meters. I just received a replacement one to keep as a spare just in case..... I decided to compare them against each other and found quite a discrepancy. Older one was reading 120ppm while the new one read 102ppm. Both are the same brand with the older only about 6 months old. They were both ebay purchases, different suppliers and I did do some readings on comparison tests and these CE brand came up near the top.
What I am asking does anyone have a recomendation for a good reasonably reliable meter.

Dirk
 

Nick potts

Member
Joined
25 Sep 2014
Messages
953
Location
Torbay
Most will have an accuracy range (typically +/- 5% of the reading), I would just split the difference and be happy with that, then just stick to 1 meter :)

Edit to add, pick up some calibration solution if you want to be sure of there accuracy. If you do get some, try to choose one as close to the range you are trying to measure as possible.
 

Kelvin12

Member
Joined
16 Nov 2020
Messages
170
Location
NSW Australia
Should have added both are reading 000 with RO water. Just reading some more and there are numerous identical versions of what I have with pricing varying all over the place so guess this is a bit of mass production with varying quality components....maybe.
Appologies for high jacking your thread, tdc999
Dirk
 

Kelvin12

Member
Joined
16 Nov 2020
Messages
170
Location
NSW Australia
Nope, only temp C and F and TDS. Sort of suggests crapy cheap Chinese item as far as I am concerned. I contacted the ebay seller, usual sort of run around, good quality, always tested before despatch and adjusted, rare to find a fault, of course. Send it back at my expense How this happens, with the adjustment before despatch is beyond me as for the love of me there is no adjustment port screw hole or any other hole for that matter to do any sort of adjustment. The thing is sealed solid. Another case of you pay for what you get.......

Dirk
 

MichaelJ

Member
Joined
9 Feb 2021
Messages
1,690
Location
Minnesota, USA
For TDS and temperature (Celsius and Fahrenheit) I highly recommend this from Hanna. Its bang on accurate in my experience - i've only calibrated it once, but I check it on a regular basis - if I make a NaCl (table salt) solution with 1 g of salt diluted in 1 liter of distilled water I get a reading hovering around 990-1010 ... and 0.5 gram I get a reading super close to 500... which is probably as good as it gets for $50... the TDS is temperature compensated and its using a fixed uS/cm to TDS conversion factor of 0.5, so converting back to uS/cm is a breeze.

Cheers,
Michael
 
Last edited:

Kelvin12

Member
Joined
16 Nov 2020
Messages
170
Location
NSW Australia
Thanks Michael I bookmarked you recomendation, currently out of stock but will keep on it.
I tried your salt mix and came up with these way off readings, 137 (old meter ) and 106 (new meter). Obviously not good so both are heading for the bin. .
 

Nick potts

Member
Joined
25 Sep 2014
Messages
953
Location
Torbay
Thanks Michael I bookmarked you recomendation, currently out of stock but will keep on it.
I tried your salt mix and came up with these way off readings, 137 (old meter ) and 106 (new meter). Obviously not good so both are heading for the bin. .

Making a calibration standard can be difficult, so before binning them I would pick up some pre-made solution HM Digital TDS and EC Calibration Solution 342ppm
 
Top