Seneye vs Liquid Test Kits in a tank emergency

Discussion in 'Water Chemistry' started by Mark D, 5 Jun 2015.

  1. Mark D

    Mark D Member

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    Yesterday was a major refurb day for my main tank, and I was expecting things to take a bit of time to settle down. However things have gone very odd, at least according the my seneye.

    Put simply the seneye has been reading a steady increase in ammonia since putting it back in the main tank (I had it in the holding tank during the work).

    So it was all up and running by around 6pm last night, and ammonia was showing .03ppm on the seneye at 9pm, so did a 25% water change (bigger this late was not an option, 25% takes about an hour), level dropped a little .027, but I had noted the seneye tends to stay high for a while after a water change if it had any non zero reading before hand.

    5.30am checked again and its shown a rise through the night to over .06ppm.
    Something did not seem right, so I got the liquid test kits I had out (I had 3, JBL - normally for my nano tank, API - Previous one for main tank, kit was running low and Nutrafin brand new set for future use on main tank)
    and while the test were developing started another water change (again 25%)

    After the water change the seneye had shown .041 and has remained stable at that level since.

    Now here is the kicker, all 3 liquid tests showed clear 0 readings

    Obviously they kind of ammonia readings the seneye are showing are very worrying and big water change plus get some zeolite etc as soon as possible would be the order of the day. But with all 3 liquid kits showing 0 I am wondering if its the seneye playing up.

    Does anyone else have experience with this?
     
  2. ian_m

    ian_m Global Moderator Staff Member

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    1. Seneye is gives false and incorrect readings in soft water.

    2. Ammonia test kits won't read correctly in presence of most dechlorinators.

    If it is a mature tank and filter, ignore and get on with watching your tank. If ammonia was around, due to substrate fiddling it will be quickly consumed by your filter, job done. If the ammonia did exist, there is no real way to tell as test kits (and Seneye) cannot accurately measure it due to the presence of interfering substance. You are probably being misled, like many other people do by test kits. You may be chasing something that doesn't exist.

    Best course is don't use test kits (or Seneye) and observe your tank.
     
    EnderUK likes this.
  3. Tim Harrison

    Tim Harrison Global Moderator Staff Member

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    Hobby grade test kits are notoriously inaccurate. Not sure about the seneye, since I've never used one, but from what I can gather from the interweb they ain't necessarily that accurate either...nice gizmo tho'. Just keep an eye on your critters, and if you feel the need keep up the water changes, I'm sure all will be fine.
     
  4. Mark D

    Mark D Member

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    Critters all seemed fine, so probably going to keep an eye on things and go back to normal wc cycle. Filter is mature, but tank was stripped bare and all new in as part of the refurb (filter had its normal heavy maintenance at the same time), so why I am little more worried than normal.

    My water is fairly hard and I normally used the Seneye as an early warning so I can take action before big problems occur
     
  5. ian_m

    ian_m Global Moderator Staff Member

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    If worried add some Prime or AmQuel to the tank daily as these will remove ammonia. In fact AmQuel is better, if growing plants, as it won't react with nitrate. When I got my tank I, which came with fish, but no mature substrate or filter media I cycled it using AmQuel daily to keep ammonia at bay, which is did and fish lived for many years.
     
  6. Mark D

    Mark D Member

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    I use prime as my standard de-chlorinater , will have a look at AmQuel when I run out
     
  7. Tim Harrison

    Tim Harrison Global Moderator Staff Member

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    I have hard water and it's never been an issue. If your filter is mature I'd trust that more than the tests, regardless of heavy maintenance or refurb.
     
  8. alto

    alto Member

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    "Hobby grade test kits are notoriously inaccurate."
    (strangely cant seem to find the "quote" shortcut :oops:)

    I see this posted constantly, but occasionally feel motivated to comment ...
    having run standard curves & "unknown" test samples for several kits - in a lab setting so spectrophotometer & cuvettes & pipettes & lab reagents etc - some are pretty decent, certainly within the requirements of most hobbyist aquaria: lab tank so ran curves/samples with tap water, RO/DI water & tank water as the solvents.

    I wouldn't publish enzyme mechanism data based upon these kits, but kits from Hach, Salifert, Elos & Seachem all performed fairly decently, even the test strips (I had Macherey Nagel) operated within claimed parameters ... could I bias them, sure, are there some compounds that interfere, sure (specific test kit reagent chemistry will usually provide a list of likely interfering substances) but in many instances these kits will provide reasonable insight into tank water parameters.

    @Troi, if you've run data to the contrary, I'm certainly interested :)

    Further, tap water parameters published by the local water district are pretty accurate, most samples are run daily, there are monthly & annual data reports, it's rare for any tap water parameters to measure outside the reported ranges - as long as I'm consistent with my tank maintenance & track my additives, my aquarium water generally reflects my expectations.

    I can't comment on the seneye as I've no experience with the system, and a quick scan of their website provides no information on the technology used in monitoring ammonia etc but a quick call to tech support should provide some troubleshooting steps.
     
  9. dw1305

    dw1305 Expert

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    Hi all,
    You are right, semi titrimetric kits for hardness etc are fairly accurate, and most tests will give you a "ball-park" figure. I think there is a problem with measuring monovalent anions, and I would take all NO3- values with a pinch of salt. Once you are into the measurement of dissolved gases like oxygen then the problems really begin. I think another problem is the "many instances", and the need for interpretation for values like pH, and an understanding of the principles of buffering etc.
    I'd definitely start with water data from your provider, as you say it is extremely accurate.

    I'm not anti-testing, quite the opposite, but it became apparent to me that people generally had unrealistic expectations of what their tests and meters could do. Because of this I looked at affordable meters and tests that would give you accurate and repeatable readings over a whole range of water types, without the need for constant calibration etc.

    The only one I came up with was conductivity. It isn't the metric you would choose, but it was a starting point.

    Having worked with both clean and polluted water I knew that biotic indices and COD/BOD were the "weapons of choice" for people working in these fields. Many years ago my research was on peat alternatives for growing ornamental plants, and again although you would try and obtain physical (air filled porosity, bulk density, shrinkage etc) and chemical (pH, nutrients etc) values, the most important test was a growth trial with a range of plants with different requirements.

    Obviously in the tank a biotic index wasn't going to help (although the state of snail shells etc may be useful), we can't measure BOD, and COD would only be useful if your tanks was so polluted that all the fish were long dead. Because I only keep planted tanks plant health was an option.

    Although we can't measure BOD, it is the lowest oxygen levels that largely define the faunal assemblage in rivers and streams, and in waste water situations we can add oxygen (often via a trickle filter) to wastes with huge BOD values to keep them aerobic, and speed nitrification. There is also a large body of work on using floating plants for phytoremediation in the tropics.

    When you combine all these strands you get the "Duckweed index". You use the conductivity meter to give you a datum for your tank water, you have large gas exchange surfaces to constantly replenish/out gas gases and you use the health and colour of a floating plant (takes CO2 availability out of the equation) to estimate the nutrient status of your tank, and when nutrients need to be applied.

    It isn't perfect but it works.

    cheers Darrel
     
    Tim Harrison likes this.
  10. Tim Harrison

    Tim Harrison Global Moderator Staff Member

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    What Darrel said...I'm not anti-testing either, in fact I find test kits useful to a point, but I'm also somewhat aware of their limitations.
     
    PARAGUAY likes this.
  11. sciencefiction

    sciencefiction Member

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    At anything below 0.1 liquid test kits will show 0. The level the seneye is showing is not really harmful.
     
  12. jaypeecee

    jaypeecee Member

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    Hi @dw1305

    There is a method for measuring aquarium BOD. I seem to recall that a 1 litre sample of tank water is removed and the dissolved oxygen immediately measured. Then, the container is sealed and put in a dark place at 20C for five days. After that period of time, the lid is removed and dissolved oxygen immediately re-measured. The difference in the two readings is the BOD. I only tried this once and it was a bit inconclusive. I think there is another method using solutions with different concentrations of KMnO4. This latter method appears to be used by pondkeepers to determine how much KMnO4 is required to treat/prevent fish diseases.

    JPC
     
  13. jaypeecee

    jaypeecee Member

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    I used to own a Seneye several years ago. One of the worst purchases I ever made. It gave inaccurate pH measurements. It was inadequately sealed as evidenced by droplets of water inside the unit. These were visible through the optical sensor 'window'. And the sensor disintegrated in my freshwater tank. Hairline cracks appeared in the casing. Apart from being in freshwater, the unit would have only had to encounter the treatments and plant ferts that any freshwater tank may have in it.

    JPC
     
  14. Ed Wiser

    Ed Wiser Member

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    In the saltwater world there is an explosion in the world of testing going on. There are testing robots that preform the test for you using regular test kits. Taking the hobbyist out of the loop which is the down fall of test kits.

    https://www.reefkinetics.com/product/reefbot-early-adopters/

    There are ion probe testing systems than can test several different parameters with a single ion probe.


    https://www.aquariumcomputer.com/products/ion-director/

    Doubt most freshwater hobbyist would get this sophisticated in testing.
     
  15. jaypeecee

    jaypeecee Member

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    Hi @Ed Wiser

    That may well be true at the moment. But I, for one, will closely watch for further developments in freshwater testing. I did hear that one major marine test company was looking at freshwater analysis.

    JPC
     
  16. Ed Wiser

    Ed Wiser Member

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    The reefbot can doing freshwater testing right now. An you can get ICP testing also right now. There is a cost involved that is a leap for many.
    I already have a lot of testing equipment with my reefing systems so I just use the same for my freshwater.
     
  17. dw1305

    dw1305 Expert

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    Hi all,
    Pretty much, that is the <"five day BOD test">. This is the <"protocol">. We used to run these, but if you can get an invertebrate sample, <"that gives you a much better estimation of pollution">.
    This is the COD test (Chemical Oxygen Demand), it uses a strong oxidising solution (potassium permanganate) to burn out any organic matter. It is a "quick and dirty test", but not fine scale enough for cleaner water. We use <"COD testing">, (with K2Cr2O7) occasionally for landfill leachate work etc.
    It is really straightforward to test sea water with an ICP. You have a lot of ions and a known range of values that you are looking for.

    Cost is an issue, ICP machines use argon as the carrier gas, and that works out <"fairly expensive fairly quickly">. It is fine if you kit is running all the time, the issue with ICP-MS is that it requires a constant feed of argon even when you aren't running samples. With AAS it only uses acetylene and/or nitrous oxide when you are running samples.
    I think there is, due to a combination of reef keepers often being people who like new technology and there being considerable running costs already to reef keeping.
    It is going to be a lot more problematic, you are looking on a much finer scale in freshwater, at a medium that is much more variable.

    Also ICP isn't going to give you all the answers you need, so you would also need HPLC and/or GC-MS, which ramps the cost up again.

    A water company would have a lab. with this kind of analytical equipment, a microbiology lab. for coliform testing, and plenty of scientists.

    This is why their water testing results are likely to be accurate, after that you can be less sure.

    cheers Darrel
     
    alto likes this.

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