Blinding Phosphates/phosphates

[dave57]

How much can phosphorus/phosphate vary on the Hanna ULR phosphorous checker for our SPS tanks?

According to the Hanna phosphorous ULR standard, a variance of 20ppb is acceptable. “Acceptable results must be between 90 and 110 ppb at 25°C”

Say you test your phosphates one day...

11 PPB= 0.033 PPM P04 (we think wow awesome my phosphates are perfect!)

Reality check
11PPB +20PPB = 21PPB =0.06 PPM P04
OR
11PPB-20PPB = zero zero ZERO

These are extreme examples but you get the idea of how much this instrument can vary. As much as we would like to know our phosphates levels and have them under control. The reality of it is we don’t know where we really stand.
Many other variables such as nuisance algae’s present in the tank, feeding habits, mechanical, biological, and chemical filtration, fish to coral ratios, lighting intensity/duration and can offset your numbers making you believe you have balanced levels.

Observation is a great tool we take for granted. Often times we overlook what is right in front of us and make decisions based on numbers we want to see pop up on a screen.

Don’t get me wrong testing will give you a ballpark, but your two own eyes can tell you if you have phosphates, just keep it stable.

People are blind to reality and only see what they want to see

-DAVID

 

[jda]

I use the Hannah Ultra Low as well. I find that if I make sure that the vials are super clean and I let the stuff sit for the 3 minutes, then I get within one or two PPB with multiple tests and it stays pretty consistent from day to day. It took me a while to figure out that the closing the top door, waiting the three minutes and wiping the vials squeaky clean is the key.

I use both vials, and swap them in/out 3 times and take an average. The other day I got something like 3, 5 and 3, so I called it 4.

All of this said, if I see any cyano beyond just a small patch here or there, then I know that my export is not keeping up with my import. After the cyano can come a bit of dinos, so that is no good either. 4 is about as high as my tank gets and this told me that the chaeto needs harvested so that it can grow faster again.