Phosphorus Ultra Low Range Colorimeter HI736 Hanna Checker - Marine Water

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  • BRStv Investigates: Which is better, Hanna Phosphate or Phosphorus Checker?

Phosphorus Ultra Low Range Colorimeter HI736 Hanna Checker - Marine Water

80% Recommend this to a friend (12 of 15)

SKU: 208630
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Quick Overview

Monitoring phosphorus concentration in saltwater is important because it can cause corrosion if levels are too high. The Hanna HI736 Checker HC Handheld Colorimeter for Phosphorus ULR bridges the gap between simple chemical test kits and professional instrumentation. Accurate, affordable and easy to use. First, zero the instrument with your water sample. Next, add the reagents. Last, place the vial into the Hanna Phosphorus Checker, press the button and read the results. Done.

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Product Questions

Which checker should I use for a reeftank the hi713 or hi736 to check for phosphate?
Question by: John on May 28, 2016 11:19:00 AM
Great question!
We use the Hi713 in most cases as it is easier to use and read over the phosphorus which requires additional calculation to convert to phosphate.
Answer by: Connor (Admin) on Jun 3, 2016 1:35:00 PM

Full Details

Hanna Checker Phosphorus Ultra Low Range Manufacturer's Manual

Hanna Checker Phosphorus Ultra Low Range Manufacturer's Literature


  • Easier to use and more accurate than chemical test kits
  • Large, easy to read digits Auto shut-off
  • Dedicated to a single parameter
  • Designed to work with HANNA's reagents
  • Uses 10 mL glass cuvettes
  • Small Size, Big Convenience
  • Fits in the palm of your hand


  • Range: 0 to 200 ppb
  • Resolution: 1 ppb
  • Accuracy: ±5 ppb ±5% of reading
  • Light Source: LED @ 525 nm
  • Light Detector: Silicon photocell
  • Environment: 0 to 50°C (32 to 122°F); RH max 95% non-condensing
  • Battery Type: (1) 1.5V AAA
  • Auto-off: After 2 minutes of non-use and 10 seconds after reading
  • Dimensions: 81.5 x 61 x 37.5 mm (3.2 x 2.4 x 1.5")
  • Weight: 64 g (2.25 oz.)
  • Method: Adaptation of Standard Method for Examination of Water and Wastewater, 20th edition, Ascorbic Acid method



Items 1 to 12 of 15 total

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  • Best Option Out There By Forsaken77 on 2/26/2017

    Unfortunately this is the best option out there for measuring low range phosphates. For those that don't know, you take the sample reading, multiply by 3.066, then divide by 1,000. This will give you phosphates in ppm. The reason you always get slightly different readings is because it's reading in ppb, which is a VERY low range to begin with and the meter has a +/- percent of accuracy because of the ultra low range.

    The problem, like others have stated, is getting ALL of the reagent into the vile even if you do it perfectly. You have to flick it all in one corner of the packet and some gets stuck in the corner. So by tapping on the packet to get it in the very tiny vile, you end up spilling a bit.

    Then, it says to shake for 2 minutes before putting the vile back in for the reading, but according to the instructions, the meter automatically shuts off after 2 minutes. Figure that one out. I haven't tested if it gives you the time to shake for 2 minutes and then will shut off 2 minutes after that, but I usually shake for 1 minute 50 seconds so I have time to wipe the vial clean and get it in the colorometer quick enough to hold the button down for its 3 minute countdown to let things settle.

    I wish there was a simple monitor with a probe that just constantly measured phosphates and nitrates. It seems these are the only 2 parameters that can't be monitored,yet they are some of the most important factors in determining algae issues.

  • Hanna H1736 By Bori on 1/22/2017

    Great and simple! Nothing more to be said about this item!
  • Great product By Paul on 10/2/2016

    This has been a great device for determining phosphate levels in a reef tank. Easy to use once you get used to the procedure. Number readout and no guessing colors.
  • It really is easy By Aaron on 7/18/2016

    I was hesitant to grab this because of a few reviews that stated it was difficult to get all of the reagent in the curvet but if you flick the packet a couple of times to get the reagent down to the bottom corner, cut the packet like instructed, and fold/roll one side to create a half funnel, it just couldn't be any easier.
  • Good By Niko on 4/3/2016

    I like it!
  • Awesome By crocogator106 on 3/30/2016

    Great piece of equipment. Exact digital readout-no trying to match colors and guessing. Very easy to use.
  • Hanna check ultra low By Nate on 3/20/2016

    Getting accurate readings and working great. you need to make sure your glass vials are cleaned and use all the reagent. Then it will work like a charm.
  • Get The Phophous Test By Sunghoon on 3/14/2016

    This one still doesn't read low enough. I should have bought the phosphorus test and done the conversion. Algae is still causing levels to be to low.
  • decent product deficient marketing approach By MaLi on 2/20/2016

    Seems to work well, but I was amazed by the fact that with the meter there are only eight (8) reagent tests. Strange and cheap given that a pack of 25 is only $9. In my opinion really bad marketing strategy. A bit of a ripoff. I will not recommend to others though I believe is a decent quality product. Hopefully marketing will learn something.
  • Easy to use, worth the price! By Jwill275 on 1/18/2016

    Easy to use, open reagent before pressing button 2nd time, gives you more time to empty reagent and mix. I always seem to have a small amount of residue in bottle but I'm very happy with results so far
  • Not for the Dain Bramaged By HANNAbanana on 9/21/2015

    Mine works great, consistently, and flawlessly. Just be careful, slow, and I have found that it helps to roll the test vial horizontally to help get rid of microbubbles before testing, if not, can cause the problems that most complain about. Also, cut the reagent packet on 2 sides.
  • poor function design By northerner on 9/3/2015

    Very difficult device to use . Preparing the meter for sample testing is a crap shoot ( meter responds different every time ) , resulting in many wasted samples and time. The powder packets are a little difficult to use and the results are probably accurate if you ever get the meter set-up. Not user friendly.