Hanna Phosphorous checker question???

[duganderson]

I'm looking at getting the Hanna Phosphorous checker (model 736 for about $50). After making the conversion to phosphate, can you measure phosphate in a tank with phosphate higher than 0.06 (the highest this checker measures) by adding 1/2 tank water and 1/2 RODI water to be measured and then doubling the result. Would this be accurate or am I'm not thinking about this correctly?

Thanks

 

[Dr Colliebreath]

We will see what the chemists have to say but I think the answer is yes.

 

[outssider]

I'm not really understanding what you are trying to do. the 736 measures up to 200 ppb. with the conversion to ppm that would be .61 ppm. If your reef is higher than that, you got serious problems.

also, don't expect ro/di water to have zero phosphorus when measured at ppb. it wont. my ro/di has about 50 ppb going in and still has traces coming out (3-5 ppb) and that is going through 3 resin chambers.

 

[duganderson]

I'm not really understanding what you are trying to do. the 736 measures up to 200 ppb. with the conversion to ppm that would be .61 ppm. If your reef is higher than that, you got serious problems.

also, don't expect ro/di water to have zero phosphorus when measured at ppb. it wont. my ro/di has about 50 ppb going in and still has traces coming out (3-5 ppb) and that is going through 3 resin chambers.

I thought the 736 only measured up until 0.06????

I made the bad assumption that RODI water would be at 0.00

 

[duganderson]

I just double checked.....the Hanna 736 tests up to 0.6 ppm phosphate. Thanks for clarifying.

Is there any value in being able to test higher than 0.6 in a phosphate spike to monitor progress toward a goal of 0.03 ppm?

 

[outssider]

they shouldn't get near that high. You need something that gives you accuracy at the very low end. measuring in ppb rather than ppm will help. Keep in mind your dealing with equipment that costs $50, don't expect absolute accuracy anyway !

 

[duganderson]

Interestingly, the results of the Hanna 713 were extremely accurate compared to a $3,500 Hach Spectrometer in the following article.....

http://www.advancedaquarist.com/2011/8/review