aquabillpers;16544 said:
Did the phosphate level rise rapidly? If so, that might be a sign that something is awry in your aquarium.
It also might be that the test kit is giving incorrect results. I think Hagen and Nutrafin merged, and the current kits emphasize the "Nutrafin" name. Maybe your kit is out of date.
You might buy a bottle of distilled water at your local food market and test it with the kit. if it is other than clear or close to it, you need another kit.
Here is a link to the results of a test I made of the accuracy of four inexpensive phosphate test kits.
http://www.aquaticplantcentral.com/...9719-a-comparison-of-four-phosphate-test.html
Bill
Bill, the human factor is really an issue here.
Some think blue is greenish blue, some think green is bluish green etc.
You ask 5 people what happened in their tank and you'll get 5 different answers..........
PO4 test kits are not that accurate over those scales really.
You an get general use from them..........
But you also need to test these test kits at more than one point.
So test at a low range, a mid range and high range over the entire range of interest.
Few do this.............
This is how you make a calibration curve just like using a pH monitor.
Some measure 1.0ppm of PO4 and think because it's accurate, then the kit is fine at 2ppm or at 0.2ppm, that's not true.
0.5, 1.0 2.0 are okay, but a factor of 10 may be better.
So 0.02, 0.2, 2.0, 20 ppm etc.
I think getting resolve at lower ends of things is extreemely important if you do any limiting work.
You did well to address issues in the test however.
I think the data you presented is well supported and should stand.
If you look at the DI and Well water data, the disturbing pattern does emerge however.
The test kits are reading detection of PO4 in non detect waters.............
So folks that think they have low levels, but not absent, are really being fooled and these test kits are totally non useful for such monitoring.
They provide okay resolution for a large wider range, "an estimation", which is not much better than EI.
That range of estimation is why I called it a estimative index.
There is a lot of error, in the time of the test taking, the other factors involved.
To try and make some precise model and specific ppms is really unrelatistic for hobbyists.
The model loses is robustnesses.
Plants are more flexible than that,
until you start getting into limiting ranges..........
Then you need high precision and accuracy, something these kits will/cannot provide.
This is why I chose to use a model that uses a higher range of nutrients, rather than just enough to barely prevent limitations.
While I can measure such relationships and have long known the issues here, many folks/hobbyists are just learning and seeing for themselves, many think I'm nuts, but if you have done the work and look and think about it, I'm not so crazy after all. But many do not do the work............or have not progressed enough to have synthesized it well.
So they still think I'm a nut etc.
A little knowledge is a dangerous thing.
I try to keep that in mind when I learn something new myself.
Regards,
Tom Barr
