Brief Hanna phoshpate spikes...test error or actual??

duganderson · 11/02/2013, 07:21 AM

My 28 g. nano cube with live rock, upflow algae scrubber, floss, purigan, BRS Rox and some macro algaes in the display. I get occasional brief spikes in phosphate according to my Hanna Phosphorous Checker. I typically only test every 2-3 weeks except for when I get a spike. For example, last night I was at 0.15 and this morning I was back to my typical 0.046

Are these bumps likely just testing error OR actual brief spikes? I know I could just re-test right away but I'm curious if it is common for folks to see large, but very brief spikes in phosphate.

Also, I'm curious if there are common causes for test errors in the Hanna Phosphorous checker. I try to follow the directions carefully.

When I got the high reading last night, I cleaned my algae scrubber which was overdue for cleaning which could have been the cause for the spike.

outssider · 11/02/2013, 05:18 PM

next time you test, fill both vials with tank water. put reagent in just one. do the test according to the instructions. after you test the correct way, try testing going back and forth between the two vials. today I tested two tanks. on tank #1 I got a 1ppb reading when testing the correct way and a 0,4,6 using the two vial method. tank #2 got a 0 when tested correctly and a 0,0,1 when using the two vial method. these are all within the accuracy limit of the 736 checker so i'm happy. I've been checking this way for a few months even though I've had the checker for years.

If you check in this way, it will put your mind somewhat at ease as to whether you really got a high reading or a fluke reading.

on a side note:
I have tested right after feeding with return pump shut off expecting a very high reading. not so. only slightly elevated reading, don't have an explanation for that!

jbfloor · 11/02/2013, 06:26 PM

Check your reagent batch lot number. If you have lot 50, e-mail Hanna and they'll send you a new batch. Lot 50 has issues.

ElmoC · 11/03/2013, 06:50 AM

Quote:

Originally Posted by jbfloor

Check your reagent batch lot number. If you have lot 50, e-mail Hanna and they'll send you a new batch. Lot 50 has issues.

He is using the phosphorus checker (HI736), not the phosphate one (HI713). The reagents for the HI736 or only in the mid 30's that I know of. Lot 25 and 26 have issues. Lot 30+ seem to be working better.

11/02/2013, 06:26 PM	#3
jbfloor Registered Member Join Date: Sep 2012 Location: San Jose, CA Posts: 250	Check your reagent batch lot number. If you have lot 50, e-mail Hanna and they'll send you a new batch. Lot 50 has issues. __________________ 72"x24"x21" 155g DSA all glass tank, 35g sump, Reef Octopus POV DC1 Skimmer DIY Lighting with 96x CREE XP-G-R5 and XT-E, UV, Orange/Red and Green LED.

11/02/2013, 07:21 AM	#1
duganderson Registered Member Join Date: Dec 2012 Location: Minneapolis, MN Posts: 569	Brief Hanna phoshpate spikes...test error or actual?? My 28 g. nano cube with live rock, upflow algae scrubber, floss, purigan, BRS Rox and some macro algaes in the display. I get occasional brief spikes in phosphate according to my Hanna Phosphorous Checker. I typically only test every 2-3 weeks except for when I get a spike. For example, last night I was at 0.15 and this morning I was back to my typical 0.046 Are these bumps likely just testing error OR actual brief spikes? I know I could just re-test right away but I'm curious if it is common for folks to see large, but very brief spikes in phosphate. Also, I'm curious if there are common causes for test errors in the Hanna Phosphorous checker. I try to follow the directions carefully. When I got the high reading last night, I cleaned my algae scrubber which was overdue for cleaning which could have been the cause for the spike. Last edited by duganderson; 11/02/2013 at 08:06 AM.

11/02/2013, 05:18 PM	#2
outssider Registered Member Join Date: Nov 2009 Location: Reseda, Ca. Posts: 1,717	next time you test, fill both vials with tank water. put reagent in just one. do the test according to the instructions. after you test the correct way, try testing going back and forth between the two vials. today I tested two tanks. on tank #1 I got a 1ppb reading when testing the correct way and a 0,4,6 using the two vial method. tank #2 got a 0 when tested correctly and a 0,0,1 when using the two vial method. these are all within the accuracy limit of the 736 checker so i'm happy. I've been checking this way for a few months even though I've had the checker for years. If you check in this way, it will put your mind somewhat at ease as to whether you really got a high reading or a fluke reading. on a side note: I have tested right after feeding with return pump shut off expecting a very high reading. not so. only slightly elevated reading, don't have an explanation for that!