phosphates

[lduncan]

Well... how did you go about testing this.

[wasp]

We've been through all that before! :roll: :roll:

[lduncan]

Funny thing is, you refused to answer that question then too.

So, how did you test these kits?

Layton

[reef]

Actually tested po4 yesterday, it was .24ppm a bit high as I have not been running rowaphos for sometime.

I put in some phos buster and just tested and the po4 was .04ppm.

Will test tomorrow again.

I think it is a bit of a fallacy that dropping po4 to quick will cause problems for acros.

I think the problem with rowaphos etc is that they also clean the water which causes the corals to burn due to the extra light they get from the clear water.

Rowaphos can also drop kh if you add too much.

[lduncan]

I think it is a bit of a fallacy that dropping po4 to quick will cause problems for acros.

It sure is. You can't kill corals doing that.

I think the problem with rowaphos etc is that they also clean the water which causes the corals to burn due to the extra light they get from the clear water.

Yip, and in tanks which have never run iron/aluminium based phosphate removers, iron/aluminium can sometimes cause problems initially.

[wasp]

Layton sorry you are upset I did not answer all your questions! :lol:

Please be aware I do not feel compelled to answer every question you ever ask! :lol:

For me, it has been a working day, it may be a shock for you but another silly argument with you has not been my no.1 priority!

Nonetheless it has been a good and productive day, I am in a good humour, I will answer this one:-

Well... how did you go about testing this.

Over the first few months since I got the Hanna I wanted to be sure it really is accurate so did a number of things, including some simple experiments.

I am no scientist though and nor do I pretend to be, Layton. So these are just simple experiments for my own use, but I doubt they will convince somebody like yourself who has already made up his mind.

One of the things I did was test the Hanna on water with a known phosphate content. The only water I can get with a known phosphate content is RODI, phosphate = 0.00. So I'd sit down once in a while and do 3 tests on RODI. Don't really know how many test I did all up, maybe 12 or 15. Also did 3 tests on other peoples RODI.

As I understand what you said earlier, you seem to think that the Hanna results could be out by as much as 0.05 per test. It is you saying things like that which is why I am suspicious that you have never actually used a Hanna, because that was certainly not what I found.

Out of all the tests I did on RODI, all but 3 came in at 0.00. The other three were 0.01, 0.02, and i THINK 0.17, or similar. The big one was a surprise, so I had a look at the curvette and found a smear on it, so would have to assume this may have interfered with the result, so have to discount that one. Also the 0.02 read was on someone elses water, so I don't know if that says something about the Hanna, or about their water.

If what you said as to accuracy was correct, the results on water with zero phosphate would be expected to range from 0.00, to 0.05. This was not the case & is why, argue as you might, I am sure of my facts.

There is more too, of my own simple unscientific experiments, which I may share at some point, but don't want to make this post an incredibly long and boring one, or more so than it already is! :lol:

[lduncan]

I thought that was the case.

You're telling me that you don't believe the accuracy claims of the manufacturer, so you did your own "experiment" (I use that term loosely) and found that they are in fact far more accurate than Hanna claim. Then you proclaim this as if what you found is actually correct, and the Hanna's testing is wrong?

We'll it might make sense to your mind, but unfortunately it's wrong.

So tossing a coin you have 50% chance of getting heads right?

Well i've just tossed a coin three times and got heads every time. So I now know that who ever said you get heads only 50% of the time is wrong, (because i have experience in tossing coins) that when you toss a coin, you will get heads 100% of the time.

Also you still haven't explained how the readings from the hanna meter are any more useful than the ones you get from a standard test kit.

Layton

[reef]

Also you still haven't explained how the readings from the hanna meter are any more useful than the ones you get from a standard test kit.

I dont want to take sides but this is what i have found.

when doing po4 testing it is important you dont get your fingers on the regents as this can make a big differance .

po4 is hard to read at low levels so most test kits will not go that low as a hanna meter. however saying that when i get readings of .02 on the hanna meter the salifert test kit will still read it when you double the sample.

using a merc test kit which is lab grade i still can get low reading however its hard to read the colours on the chart. i find using the hanna meter gives me a number so i dont have to worry about my eye guessing which colour it is.

i am still not sure if readings of say .05 are bad for a tank as i have seen tanks with readings of .20 and still have nice acro colours. i cant understand why no one can do a organic po4 test kit. actually they can however you have to heat the sample etc, sounds like it takes a long time. i already hate doing a strontium test.

[wasp]

Layton you are just being argumentative. The results were what the results were.

I think what you may be missing is that the manufacturers claimed variances are the extreme outer limits. They may never get hit, and in this case of real world use, they were not.

You also asked another question about my other tests. Happy to tell you, but to be frank, you are simply being an argumentative, aggresive, jerk.

Chill a bit and we can discuss this more sensibly.

Oh, and a more open mind would not kill you either. I strongly suspect that you have never actually used the Hanna, so why such strong opinions despite my experience I have shared?

[wasp]

Thanks for the common sense Reef.

I am sure Layton may be able to accept that as common ground.

[lduncan]

Layton you are just being argumentative. The results were what the results were.

I think what you may be missing is that the manufacturers claimed variances are the extreme outer limits. They may never get hit, and in this case of real world use, they were not.

You also asked another question about my other tests. Happy to tell you, but to be frank, you are simply being an argumentative, aggresive, jerk.

Chill a bit and we can discuss this more sensibly.

Oh, and a more open mind would not kill you either. I strongly suspect that you have never actually used the Hanna, so why such strong opinions despite my experience I have shared?

This just shows your total ignorance in this area. You can't make the claims you have made, from what you've done. It's so wrong it's not even funny.

[wasp]

You asked me to tell you about the experiments i did.

When I didn't answer fast enough you complained.

I then told you what I did, as per your request.

Again, the results were what the results were.

You then tell me this shows how ignorant I am.

Whatever...... you are impossible....

[Feelers]

I agree with Wasp, anecdotal evidence suggests that those tests are more accurate than the ratings given by the manufacturer.

This is based on what I've seen of other people experiences also, if you look at all the super skimmed tanks they have a phosphate of 0 on the test. Now you say flipping a coin but it if it keeps coming up heads enough the results are probably significant.

What I would imagine is that for x amount of tests produced, say 10 in every hundred will be way outa whack.

So the varience is wide which shifts the average accuracy disproportionately away from the median.

If what your saying is the case Layton heaps of the ultra low nutrient tanks would be getting .3 or .4 ratings at least some of the time, and I have not seen much if any evidence of this. Sure it may occur, and what most people do is another test which goes back to the usual result.

[Warren]

This just shows your total ignorance in this area. You can't make the claims you have made, from what you've done. It's so wrong it's not even funny.

Lduncan, I wish you'd stop being so disagreeable and argumentative all the time (it would appear you can't help yourself). The marine threads would be better for it. While your posts are sometimes mildly entertaining they are generally destructive. Unless you can actually offer constructive criticism (and offer it in a nice way), please don't bother and let everyone else get on with it.

[lduncan]

Again, the results were what the results were.

But that doesn't make the conclusions you draw from those "experiments" correct.

They are highly unscientific. Fundamentally flawed, and you can not draw the conclusion you have from the method you've followed.

Hanna has stated the accuracy of there meter:

+/- 0.04 +/- 0.01 +/- 4% of the reading.

None of your experiments are rigourous enough to even start to dispute that. It shows your ignorance of scientific process, experimental technique, and testing principles

The best reading you can get from a Hanna meter is 0.00 +/- 0.05ppm

If you think otherwise, I'm sure Hanna would like to know.

Also, you still haven't explained how the readings you get from a hanna meter are any more useful than those from a standard test kit.

Layton

[Warren]

So what!

At least he's trying to help.

Looks like what he's offering is better than the results from kits and most likely helpful to most people. Just let it go and accept it's not perfect... :roll:

[lduncan]

It's not perfect, it's not even close, it's absolutely wrong.

What he's saying is not helpful at all. It's absolutely misleading.

Layton

[Warren]

Oh, just give it a rest... :roll: :roll: :roll:

[Feelers]

Well what about all the points that I brought up? Why do incredibly low nutrient taks consistantly get nil phosphate readings?

At the same time tanks that have higher levels consistantly get detectable levels.

I'm well aware of the science involved, but I can still see from anecdotal stastical evidence that these tests seem to be a lot more on the money than plus or minus 0.05.

If you keep tossing a coin and it comes up heads time after time, you have to check to see whether its statistically significant.

[lduncan]

Was the colorimeter calibrated?

[lduncan]

I'm well aware of the science involved, but I can still see from anecdotal stastical evidence that these tests seem to be a lot more on the money than plus or minus 0.05.

Then you of all people should know how wrong this is. Just remember what anecdotal means:

Anecdotal - (of an account) not necessarily true or reliable, because based on personal account rather than facts or research

And some reading:

http://en.wikipedia.org/wiki/Anecdotal_evidence

http://en.wikipedia.org/wiki/Availability_heuristic

http://en.wikipedia.org/wiki/Neglect_of_Probability

http://en.wikipedia.org/wiki/Endowment_effect

I'm sure if anyone can show that the Hanna meter is more accurate than Hanna themselves say, they would be happy to hear from them. I'm sure they'd amend their marketing material in a second.

Layton

[dogmatix]

LOL i just read this thread and all i can say is unbelievable :roll: :roll: :roll:

[Warren]

Yup

[JDM]

not all company's market there products in a "best case" scenario, especially those that sell in countries that have strict laws on such marketing.

if they say it has a margin of 0.05ppm this may be what there tests have shown as the worst case, not the standard reading or the bench mark.

i work with products that are designed and engineered in USA, these products use a worse case reading, they are under normal conditions much better than the manufacturer claims, this way there is little chance of a law suit being lodged and the proceeding costs involved.

just my opinion. i think there is many factors that would make the Hanna more useful for the hobbyist, the fact of not having to determine the color of the test sells me on the meter, ease of use in comparison the tests, etc etc.

i would be interested to see what my water tests on with the Hanna compared to the (very good) salifert test.

[shaneo]

Thought I was gunna read a thread that would help me with phosphate issues but other than the first post I have wasted 15 minutes of my time.