Hanna or Redsea

seargentslice · Dec 12, 2013

Quick ? I hava hanna checker that is reading 0.00 on both test vials And red sea that reads .36 I typically just change gfo when i see increased algae on glass and decided to test just to see where it was at. The hanna is about 8mnths old and would always give me readings i agreed with till now mabe ill change the batt and see if it reads any diff just wondering if anyone else had them malfunction.

Tradewinds · Dec 12, 2013

Which parameter are you testing?

Velodog2 · Dec 12, 2013

I'm assuming phosphorous or phosphate since you refer to gfo. Which Hanna checker do you have? There is a high level phosphate and a low level phosphorous. The low level checker has much better resolution.

seargentslice · Dec 12, 2013

Ok sry its the phos hi 713 its always given me readings before I did just buy a new lot of Regent 100 test expires 3/ 20 15 I don't know if it would be an issue with the reagent or the checker itself

Tradewinds · Dec 12, 2013

On another board there was some discussion regarding the accuracy of the Hana phosphate checker and one individual said they trusted the Hach PO-19 kit. I did a search and it looks like it would be a nice test kit, although it is a little pricey.

Velodog2 · Dec 12, 2013

Hanna is notorious for lousy quality control of reagents and subsequent problems. If the lot number is all you have changed I would strongly consider that as a possibility. Obviously if you have any older reagent left then check it with that. Which reading would you expect to be correct or typical, the zero or the 0.36, and are you getting algae outbreaks? If the readings are believable I would tend to go with the RedSea if you haven't changed anything about the test and it has been accurate in the past.

seargentslice · Dec 12, 2013

No outbreaks but it is definitely higher than zero get the light Haze on the glass daily that's a little heavier than normal sadly I do not have an old Regent but assuming that it was correct . .04 would normally be the reading with the old Regent when I'm observing the same amounts of algae I hardly ever check it anymore but since reading I'm trying to balance my amount of GFO to keep my po4 around .03 for better SPS color I used to run too much GFO keeping my readings 0 and ended up turning my panape up a bird's nest pale pastel colors

seargentslice · Dec 12, 2013

What do you guys think about this brand Martini MI-412 Phosphate Colorimeter, Low Range - AquaCave.com

Velodog2 · Dec 12, 2013

It's important to keep in mind that the Hanna 713 is only accurate to +/- 0.04 ppm phospates. If you are trying to control it in the 0.03 range it will not be a great tool for you. I don't know the accuracy of the RedSea.

Ignoring the Hanna for now, and regardless of the precision of the RedSea, 0.36 is a lot higher than the 0.03 target or the 0.04 expected. How long has it been since you last checked phosphates and got an expected reading? And I assume you have double-checked each test. You could treat a small sample of tank water with gfo and retest it with the RedSea to see if there is a reduction in order to confirm that there are phosphates present.

seargentslice · Dec 12, 2013

Velodog2 said:
It's important to keep in mind that the Hanna 713 is only accurate to +/- 0.04 ppm phospates. If you are trying to control it in the 0.03 range it will not be a great tool for you. I don't know the accuracy of the RedSea.

Ignoring the Hanna for now, and regardless of the precision of the RedSea, 0.36 is a lot higher than the 0.03 target or the 0.04 expected. How long has it been since you last checked phosphates and got an expected reading? And I assume you have double-checked each test. You could treat a small sample of tank water with gfo and retest it with the RedSea to see if there is a reduction in order to confirm that there are phosphates present.

Ok just tested water out of my GFO reactor with fresh GFO getting .08 redsea Now my question is what is a reliable or most accurrate p04 test out there? You see everyone posting .01 to .03 for po4 gives best coloration. Ik its bin 3 weeks with my tank running higher po4 and my hanna giving me 0.00 so what prompted me to check with red sea. Ill say 1 thing my birdsnest has gotten its color back with very deep pink tips almost red.

Velodog2 · Dec 12, 2013

Tough question that there has been some discussion of. IMO the two contenders are the RedSea kit you have, and the Hanna 763 low-level phosphorous checker.

The 736 claims accuracy of +/- 5 ppb of phosphorous, which needs to be multiplied by .0031 to get equivalent ppm phosphate, giving accuracy of about +/- .015 ppm phosphate. But it still has the problems associated with Hanna products. I have that tester and I have significant issues with consistency if I use the procedure they supply. Others seem to have better luck.

Bottom line is it's tough to measure phosphates at the level that they have an effect on our reefs because that level is so very low.