# Nitrate Tests?



## tdc999 (9 Nov 2021)

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.


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## Nick potts (9 Nov 2021)

tdc999 said:


> I have been testing the water with the API freshwater test kit.
> 
> Apart from the Nitrate all the other tests are very good.
> 
> ...



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 Having said that a test kit that is 16 years out of date no matter is not going to be any good.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.


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## dw1305 (9 Nov 2021)

Hi all,


tdc999 said:


> 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.


tdc999 said:


> 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.





tdc999 said:


> 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


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## tdc999 (9 Nov 2021)

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.


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## dw1305 (9 Nov 2021)

Hi all,


tdc999 said:


> 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


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## MichaelJ (9 Nov 2021)

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.







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


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## Rockfella (9 Nov 2021)

MichaelJ said:


> View attachment 177050


I can never see diff between 40/80. So unless it becomes deep red or orangish I will assume it to be 80.


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## ian_m (10 Nov 2021)

Why you shouldn't really bother with test kits, as you have found out.
What about Test Kits ?


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## tdc999 (10 Nov 2021)

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.


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## Nick potts (10 Nov 2021)

tdc999 said:


> 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?
> 
> ...



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.


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## dw1305 (10 Nov 2021)

Hi all, 


tdc999 said:


> Has anyone got experience with this type of meter.


Cheap ~€50 conductivity meters <"are fine">.  I'm not personally a fan of <"cheap pH meters">.


Nick potts said:


> I can't see a link,


Same for me.

cheers Darrel


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## erwin123 (10 Nov 2021)

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


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## Kelvin12 (10 Nov 2021)

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


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## Nick potts (10 Nov 2021)

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.


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## Kelvin12 (10 Nov 2021)

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


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## dw1305 (11 Nov 2021)

Hi all, 


Kelvin12 said:


> Older one was reading 120ppm while the new one read 102ppm


You should be able to <"recalibrate them">. 

Set them to "Electrical Conductivity (EC)" in microS.  They will probaby have three options "ppm TDS", "EC" and "salinity".  They all <"measure electrical conductivity"> and then use a conversion factor to estimate ppm TDS etc. 

cheers Darrel


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## Kelvin12 (12 Nov 2021)

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


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## MichaelJ (12 Nov 2021)

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


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## Kelvin12 (12 Nov 2021)

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. .


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## Nick potts (12 Nov 2021)

Kelvin12 said:


> 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


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## MichaelJ (12 Nov 2021)

Kelvin12 said:


> 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. .


Hi @Kelvin12  You need an accurate scale (milligram resolution) to measure out the 1 gram of pure NaCl and an accurate measure for the 1 liter of distilled water,  make sure the salt is throughly diluted and ideally making sure the solution is at room temperature when you measure.  If both probes comes out close to 100 ppm I suspect the solution mix is off, so I wouldn't toss the probes just yet.

Cheers,
Michael


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## jaypeecee (12 Nov 2021)

tdc999 said:


> I now have Pro JBL Aqua test.
> 
> The Nitrate reading is between 15 and 30.
> 
> ...


Hi @tdc999 

I use JBL test kits and they serve me well. Just ensure that you store them as JBL recommends. And, although manufacturers don't explicitly state this, it may be advisable to use the kit within six months of starting to use it. An expiry date will be stated on the box but this will likely be in excess of six months. I suspect that the JBL Test Kits are produced by Macherey-Nagel.

JPC


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## jaypeecee (12 Nov 2021)

MichaelJ said:


> ...if I make a NaCl (table salt) solution...


Hi @MichaelJ 

Is it worth pointing out that some Table Salt is not pure sodium chloride (NaCl) but may contain other substances to enable the salt to flow readily?

JPC


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## MichaelJ (12 Nov 2021)

jaypeecee said:


> Hi @MichaelJ
> 
> Is it worth pointing out that some Table Salt is not pure sodium chloride (NaCl) but may contain other substances to enable the salt to flow readily?
> 
> JPC


Yes, thats  key... it needs to be +99% NaCl - we call it table salt, but there can be all sorts of other ingredients in regular kitchen salt. My wife prefer to cook with "table salt" that has a vintage merlot flavor 
I don't think it would skew the measurement an order of magnitude though...

Cheers,
Michael


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## Kelvin12 (12 Nov 2021)

Unfortunately neither of these TDS meters are adjustable so calibrating is not an option.  I have ordered another TDS, X1AOMI Mi (not the same as above) from an aquarium dealer I have used before for a number of items and been happy with the service and quality of their stuff.   If this turns out OK I am happy.  It will do at least for the time being until the Hanna one is back in stock. stock.

About the only thing I can find about this salt is that its potassium iodate??

Dirk


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## MichaelJ (13 Nov 2021)

Kelvin12 said:


> Unfortunately neither of these TDS meters are adjustable so calibrating is not an option.  I have ordered another TDS, X1AOMI Mi (not the same as above) from an aquarium dealer I have used before for a number of items and been happy with the service and quality of their stuff.   If this turns out OK I am happy.  It will do at least for the time being until the Hanna one is back in stock. stock.
> 
> About the only thing I can find about this salt is that its potassium iodate??
> 
> Dirk


Sounds like iodized salt to me. Perhaps look into buying a calibrated NaCl solution as suggested by @Nick potts  above. 

Cheers,
Michael


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## Kelvin12 (13 Nov 2021)

Yes I think that is a very good option for sure. I found your recomendation here in AU which is good.  Thanks everyone for the assistance. 
Dirk


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## harryH (15 Nov 2021)

I was going to ask the question about high nitrates but found this thread.
I just have a 10 gallon tank, running a couple of months. Plants are great (heavily planted) and responding well to the CO2 and after battling algae for the first few weeks I'm struggling to find any at all, water is gin clear. Fish are in rude health.
I've been using Tetra 6 in one strips and while they are very convenient I find  they can be difficult to read with any confidence.
The strips show my nitrates from the tap at 80 -100 and exactly same in the tank. I went onto Anglian water site and found their readings which say Nitrates in the 30's. There is a caveat however stating farmers using fertiliser may up the nitrate readings from time to time and I do live in Lincolnshire which is very agricultural and has hard water.
From the strips my other readings are PH 7.5, GH 8-10 and KH 10 -18, again KH is difficult to read. Needless to say Nitrites 0 .
My thoughts are to trust my eye as regards nitrates as it doesn't appear to be having any adverse effects and I don't want to start messing with water parameters..
Thanks guys for all the information you post on here and any comments on my situation would be most welcome. hope I've added to rather than hijacked the thread.


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## bazz (15 Nov 2021)

Hi,
I may be wrong but living in Lincolnshire I would imagine your GH is most probably around twice as high as 8-10. I'm in Lincoln and I've just this moment tested my tap water which is GH19, although this too will be an inaccurate reading it has always hovered around this value whenever I've tested it over the last 45 years.
Cheers!


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## dw1305 (15 Nov 2021)

Hi all,


jaypeecee said:


> Table Salt is not pure sodium chloride (NaCl) but may contain other substances to enable the salt to flow readily?


It does, added as an anti-caking agent.  It used to be magnesium carbonate (MgCO3), but now it is usually sodium hexaferrocyanide (Na4Fe(CN)6).


MichaelJ said:


> Yes, thats key... it needs to be +99% NaCl - we call it table salt, but there can be all sorts of other ingredients in regular kitchen salt. My wife prefer to cook with "table salt" that has a vintage merlot flavor
> I don't think it would skew the measurement an order of magnitude though...


I don't know exactly how much is added, but I'm going to guess "_not very much_" and that it makes less than 5 microS difference.

cheers Darrel


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## dw1305 (15 Nov 2021)

Hi all, 


harryH said:


> The strips show my nitrates from the tap at 80 -100 and exactly same in the tank. I went onto Anglian water site and found their readings which say Nitrates in the 30's. There is a caveat however stating farmers using fertiliser may up the nitrate readings from time to time and I do live in Lincolnshire which is very agricultural and has hard water.


The EU limit (which we are adhering to) for drinking water is 50 ppm NO3. It is sometimes breached, but all breaches should be reported on the <"Anglian Water web site">.


bazz said:


> I would imagine your GH is most probably around twice as high as 8-10. I'm in Lincoln and I've just this moment tested my tap water which is GH19, although this too will be an inaccurate reading it has always hovered around this value whenever I've tested it over the last 45 years


That sounds about right. Approximately 18 dGH & 18 dKH are the equilibrium values for water <"saturated with calcium carbonate"> from a limestone aquifer. The workings are in Larry Franks very useful article on <"water hardness at the Krib">. 

cheers Darrel


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## harryH (15 Nov 2021)

Thanks for that Bazz yes I think I am reading what I'd like it to be rather than what it is😉, as I say the strips are not easy to read and the subtle colour changes  coupled with the smudges the water can give on them doesn't help. Your figures sound much more plausible,. I'm out on the coast near Cleethorpes where Anglian water say the tap water is 16.302 dH.


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## harryH (15 Nov 2021)

dw1305 said:


> Hi all,
> 
> The EU limit (which we are adhering to) for drinking water is 50 ppm NO3. It is sometimes breached, but all breaches should be reported on the <"Anglian Water web site">.
> 
> ...


Cheers Darrel, there's no breaches reported and ave fig. is 39.1 nitrates. Hardness is reported as Calcium Carbonate 287 mg/l,  Calcium 114.8 mg/l, German Hardness 16.303 dH.


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## bazz (15 Nov 2021)

harryH said:


> Thanks for that Bazz yes I think I am reading what I'd like it to be rather than what it is😉, as I say the strips are not easy to read and the subtle colour changes  coupled with the smudges the water can give on them doesn't help. Your figures sound much more plausible,. I'm out on the coast near Cleethorpes where Anglian water say the tap water is 16.302 dH.


What I was trying to suggest is that test strips and entry level titration kits are notoriously unreliable and sometimes difficult to correlate with the provided colour charts.
Cheers!


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## dw1305 (15 Nov 2021)

Hi all,


harryH said:


> yes I think I am reading what I'd like it to be rather than what it is😉, as I say the strips are not easy to read and the subtle colour changes coupled with the smudges the water can give on them doesn't help.


That was partially why I went to using

plant leaf colour and health and
conductivity
as my <"test strip">.  There is <"little margin for error"> and <"the plants are providing">, what I now know, are <"ecosystem services">.


> _........ Plant/microbe filtration provides a negative feedback loop where enhanced levels of fixed nitrogen lead to enhanced plant growth, which leads to <"higher oxygen production">, which leads to the ability to process more fixed nitrogen. When you remove that plant growth you've exported that nitrogen from the system......._


cheers Darrel


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## harryH (15 Nov 2021)

This is my little aquarium as it looks, I've been out of the hobby quite some time but not too bad, I am 81 years young after all but once bitten🤣. I just want something to keep me occupied and trying to do it right but keeping it enjoyable.
Thanks for replying guys


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## sparkyweasel (15 Nov 2021)

harryH said:


> Plants are great (heavily planted) and responding well to the CO2 and after battling algae for the first few weeks I'm struggling to find any at all, water is gin clear. Fish are in rude health.


I wouldn't wory about anything else. 


harryH said:


> My thoughts are to trust my eye as regards nitrates as it doesn't appear to be having any adverse effects and I don't want to start messing with water parameters.


That sounds good.


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## jaypeecee (15 Nov 2021)

harryH said:


> This is my little aquarium as it looks, I've been out of the hobby quite some time but not too bad, I am 81 years young after all but once bitten🤣.


Hi @harryH 

If, and when, I get to 81*, I hope I can have tanks that look as good as yours! Well done!

* I've got 13 years to go!  

JPC


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## harryH (15 Nov 2021)

jaypeecee said:


> Hi @harryH
> 
> If, and when, I get to 81*, I hope I can have tanks that look as good as yours! Well done!
> 
> ...


Hi mate and thank you, I retired at 60 and the only thing I regret is time has flown. I can't do half the things I could in the garden but keeping a planted tank is just another kind of gardening and as long as I don't end up with all the tanks I once had I should be okay at keeping the Mrs sweet.😂


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## Kelvin12 (24 Nov 2021)

MichaelJ,  I took your advice here and bought the Hanna TDS meter you recommended.  It took a while butb worth it Its brilliant and came with 4 sachets of test solution for future calibration.   I checked the Hanna reading against 3 cheap Chinese TDS and the difference in reading on the cheap meters was way out and I mean way out and this despite one seller assuring me his meters are always tested before they leave the wharehouse.   I wonder in what they were tested. 

Thanks again Michael and everyone else here for the advice it was appreciated.  This truly is a great forum.   

Dirk


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## jaypeecee (29 Nov 2021)

Kelvin12 said:


> I took your advice here and bought the Hanna TDS meter you recommended.


Hi @Kelvin12 

Hanna products are good. I have four of their devices. In the UK, their prices are high compared with the USA. I don't know about Australian pricing.

It is totally false economy to buy cheap meters. This is one of those situations when you get what you pay for. In terms of technical complexity (the device innards), TDS & EC meters are simple bits of kit. This is followed by thermometers and then, pH meters. Almost at the top of the ladder are ORP/Redox meters. And, finally for we hobbyists, there are what are known as photometers - this would correspond with Hanna's _Checker_ range.

JPC


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## Nick potts (29 Nov 2021)

jaypeecee said:


> Hi @Kelvin12
> 
> Hanna products are good. I have four of their devices. In the UK, their prices are high compared with the USA. I don't know about Australian pricing.
> 
> ...



Maybe my understanding is wrong, but I thought the hanna checkers used the same testing methods as a standard test kit, but the electronics read the colour change, Wouldn't that make them only slightly better (on the basis the machine can read the colour better than the human eye)

I have owned a few of the meters for reef tanks and always liked them for ease of use.


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## Kelvin12 (30 Nov 2021)

I would be happy with a reasonable easy to read liquid test kit.   I saw Hanna have a hardness liquid checker but it doesn't mention if its a GH / KH kit.   I was going to chase it up in the new year.


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## Nick potts (30 Nov 2021)

Kelvin12 said:


> I would be happy with a reasonable easy to read liquid test kit.   I saw Hanna have a hardness liquid checker but it doesn't mention if its a GH / KH kit.   I was going to chase it up in the new year.


You have a link to the kit?


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## Kelvin12 (30 Nov 2021)

The Sera Kit I had in mind was the GH test.   They do make a full kit though with a few more tests than API pro. but its a bit more expensive, well at least over here in Australia which isn't  unusual......  around the $100AU  plus.   From what I have read to date its an easier test to read.   
I can't do a link unfortunately and no idea how to do than on my tablet but if you Google,  Sera aquarium test kit it comes up.


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## Kelvin12 (30 Nov 2021)

Sorry Nick Pots misread your post. 

From HANNA AU  the part number is  H 13840.  I would assume its the same part number the world over.   It says its total hardness kit ?   Price is right if it does the job, $18-70


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## jaypeecee (1 Dec 2021)

Nick potts said:


> Maybe my understanding is wrong, but I thought the hanna checkers used the same testing methods as a standard test kit, but the electronics read the colour change, Wouldn't that make them only slightly better (on the basis the machine can read the colour better than the human eye)


Hi @Nick potts 

Indeed, you are correct. The photometer test kits often use the same basic chemistry but eliminating colour matching is a major step forward as far as I'm concerned. Particularly at the low end of the test range. Colour perception is dependent on ambient lighting and this can pose a problem. As with all things, we have to set a price limit on what we're prepared to pay. I guess the next level up is the ISFET* electrode but we're looking at £300+.

* Ion-Sensitive Field Effect Transistor

JPC


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