Iodine v iodide test kits

[chicago]

Help me out.

1. Hana test kit for iodine always show zero
2. but my seacheme test kit for iodide shows .06

Does that make sense. I realize they are two different elements but wondering and need some clarification.

Also.. I was dosing carefully loguls.. but ran out so now using seachem reef iodide. Thoughts thanks

 

[GoVols]

Help me out.

1. Hana test kit for iodine always show zero
2. but my seacheme test kit for iodide shows .06

Does that make sense. I realize they are two different elements but wondering and need some clarification.

Also.. I was dosing carefully loguls.. but ran out so now using seachem reef iodide. Thoughts thanks

Welp,
Looks like Randy covers it in this article
https://www.advancedaquarist.com/2003/3/chemistry

Pretty long write up... ;Bookworm

Read on down, he talks about testing and dosing.

 

[Dkeller_nc]

There might be a reason for your Hanna results. That meter uses the DPD quantitative iodine method from Standard Methods for Analysis of Water and Wastewater - free iodine reacts with N,N-diethyl-p-phenylenediamine to form a pink color. I seem to have misplaced my Standard Methods copy, but I don't think that test will react with iodate (IO3-) nor iodide (I-), and any iodine (I2) you add to your tank would be rapidly converted to these two species. Reading the Hanna package insert, it appears it is primarily intended for the monitoring of freshwater swimming pools.

The Hach writeup on their DPD iodine method notes that one of the interfering substances for this test is alkalinity, and there's a recommendation to acidify samples to prevent the pink color from the DPD from either not developing or fading instantly. The Hach assay notes that the alkalinity would have to be pretty high for this to occur (>250 ppm, or 14dKH), and notes that this level of alkalinity will overcome the acidifying effect of the reagent that Hach provides. Hanna doesn't have this information, so it's not clear whether their reagent packs would have sufficient acidity when mixed with the 10mL seawater sample.

 

[chicago]

Thanks for the insight.. I must say.. I think i wasted my money on that one. I noticed with more research it seems to be for swimming pools.. Freshwater.. I have test many times and never saw a hint of pink...

 

[adrianr514]

Thanks for the insight.. I must say.. I think i wasted my money on that one. I noticed with more research it seems to be for swimming pools.. Freshwater.. I have test many times and never saw a hint of pink...

Yeah, unfortunately you’re correct. The Hanna checker isn’t meant for a marine environment.

 

[chicago]

Yep .. learned the hard way.. waste of money.. I now use the Seachem... its a little bit of a pain in the butt.. but.... did i say that...? anyways... I actually have learned to like the seachem.. you make a testing solution before hand... and given the testing tray has six domes to test... i can test the frag QT and the DT at the same time..

 

[adrianr514]

Yep .. learned the hard way.. waste of money.. I now use the Seachem... its a little bit of a pain in the butt.. but.... did i say that...? anyways... I actually have learned to like the seachem.. you make a testing solution before hand... and given the testing tray has six domes to test... i can test the frag QT and the DT at the same time..

I use the Seachem one as well but I absolutely hate the sliding key it comes with. Once I'm out of this one I'm going to try the red Sea one.

 

[chicago]

Agreed.. i used the reference water sample it comes with at .06 to make sure my eyes are seeing .06 .. I like Seachem but have always had issues with their sliding scale.. just too much play for my eyes..