Reef Discussion

[potatocouch]

What do you think of the idea purchasing 736 and then doing the math:
Multiply your reading by 3.066 to convert P to PO4
Then divide by 1,000 to convert to ppm.

Does one need to go that ULR or 713 would usually suffice?

View attachment aglassbox_design.com_wp_content_uploads_2010_06_hanna_checker_ppb.jpg

 

[bimbo]

depends what you want out of it - are you running ULNS tank? if not then the 716 will be fine. I use the 736 and just do the math. either way they will both be quite a bit more accurate than trying to match vials of water up against a colour chart

 

[daveH]

I have both but tend to use the 713 over the Phosphate tester. Although I've read a number of times that the Phosphate is more accurate - I guess it's just what you get use to. There is a chart you can download that takes all the maths out of it for you.

 

[IJG3145]

I've noticed that the trend is definitely moving toward testing phosphorous rather than phosphates.

 

[Sam Parker]

I had heard that the checker itself is exactly the same and is just dividing the result that you then multiply?

 

[potatocouch]

I've noticed that the trend is definitely moving toward testing phosphorous rather than phosphates.

Because probably they're lower detailed level as opposed to phosphate.

I had heard that the checker itself is exactly the same and is just dividing the result that you then multiply?

That's how I understood as well.

 

[MagicJ]

A post I found from Randy Holmes-Farley

FWIW, I would have recommended the 736. The range of uncertainty claimed by the manufacturer for the 713 is too large (IMO) at +/- 0.04 ppm. That means a reading of 0.00 could be 0.04 ppm in reality, and 0.04 ppm could be anything between 0.00 and 0.08 ppm.

The 736 does indeed measure exactly the same thing (only inorganic phosphate), but for marketing reasons chooses to report it as ppb phosphorus. Once you convert it into ppm phosphate, its uncertainly is still +/- 0.015 ppm, but it is better than the 713 and adequate for most reef uses. :)

 

[potatocouch]

You can't go wrong with @Randy!

 

[MagicJ]

You can't go wrong with @Randy!

I tend to believe anything he has to say about water chemistry or related subjects :worship

 

[Sam Parker]

I honestly doubt that the 736 is any more accurate, it is the same technology and the same reagent process?

 

[Sam Parker]

update, after researching post-opening my mouth, I now see that it has a lower range and therefore has a more precise reading. Sounds fair

 

[dimitri]

this thread explains the differences and why you want the Phosphorus one.

I bought the UL phosphorus one as it gives you total compounds pre conversion into phosphate, by which point they start to get taken up by algae etc and then give you a false positive / untrue value

http://www.reefcentral.com/forums/showthread.php?t=2066574