Best Phosphate Test Kit

Beefer

New member
What does everyone use to measure phosphates? I have an API test kit, but it is impossible to read under 1ppm. Is there a test kit that allows you to read a lower range? I really don't want to spend $200 for a phosphate meter. I want to be able to determine when to change GFO.
 
I dont know if you guys can get them in the US, but the DD-Merk kit is the best over here, and accurate reading from 0.000-0.008-0.015 etc
 
the DD-Merck kit is the best over here, and accurate reading from 0.000-0.008-0.015 etc..

That is a very misleading post. That kit expresses Phosphate as PO4-P and not PO4. So, its true reading of 0.008 -0.14 is really;

PO4 = PO4-P 0.008 - 0.14 x 3.06 = 0.024 - 0.049 ppm PO4

A HACH PO-19 is 0.02 - 1 .00 ppm

In this hobby we use PO4 and not P-PO4

its very accurate

Based on what ? Have you tested it against a known ref std ?
 
you can change your gfo once a month, or if you have to clean your glass often. I clean my glass once a week. I just use presence of algae to tell me if po4 is not zero. its a reliable indicator. you can still get a zero reading on photometer and still have algae. I used to use a photometer, but has since sold it.
 
you can change your gfo once a month, or if you have to clean your glass often. I clean my glass once a week. I just use presence of algae to tell me if po4 is not zero. its a reliable indicator. you can still get a zero reading on photometer and still have algae. I used to use a photometer, but has since sold it.


+1 me too :thumbsup:
 
I would like to know an answer to this as well. But so far no cocensus. Anyone else want to suggest a brand (so that someone else can discredit it)?
 
The hanna phosphate seems like the best option that I've seen so far.

I think I might just go with what I have been doing. I currently change GFO every month, clean the glass about every 5 days, and never have any nuisance algae in the tank. Just want my SPS to stay healthy as possible, and grow at maximum rate.
 
I need a good Po4 tester. The colors are always hard to read, and i always try to convince myself its a lower reading. lol an actual # would be way better.
 
the DD-Merck kit is the best over here, and accurate reading from 0.000-0.008-0.015 etc..

That is a very misleading post. That kit expresses Phosphate as PO4-P and not PO4. So, its true reading of 0.008 -0.14 is really;

PO4 = PO4-P 0.008 - 0.14 x 3.06 = 0.024 - 0.049 ppm PO4

A HACH PO-19 is 0.02 - 1 .00 ppm

In this hobby we use PO4 and not P-PO4

its very accurate

Based on what ? Have you tested it against a known ref std ?

The kit mesures p04-p and p03/4
 
I went to the LFS two weeks ago with this very concern.
After realizing that API's test kit was not very useful for really low levels
I wanted another test kit to get lower then 1 ppm.

I read the directions for several kits and i decided to try out SERA.
I find that the colors are easier to read compared to others if you follow
the directions closely and use it during the daytime. The colors are still
close together but in the normal test you are looking for 0, .25, .50, 1, and 2 ppm

Pure ro/di water was easy to see as 0 using the color chart. The difference between
.25 and 1.0 is quite dramatic color wise with their blue scale.

So... that is what I went with. I will research this Hanna meter everyone is talking
about. It would be nice to have it if it is reliable and does not need calibration every
other month.
 
I have the Hanna Phosphorus ULR checker HI 736. It's easy to read the number as compared to a color chart. As far as accuracy it may not be better than a top notch phosphate kit but IMO better than API & Salifert.

This meter measures Phosphorus, so you'll need a little math to get PO4. The phosphorus checker HI 736 is slightly more accurate than the Phosphate HI 713.

Math is easy, example:
12 ppb (example of reading) x 3.066 (factor to convert to PO4) = 36.792 ppb PO4 / 1000 (to convert ppb to ppm) = .037 ppm PO4
 
Buy the Hanna Checker for PO4. I have been using a Salifert Test and it was giving me a zero, but I was actually at .55. Changing the GFO too often can be expensive and detrimental. If you were to get a true zero you could strip the phosphate from your corals. So I was advised...difficult, but possible. I run 150grams of GFO in a reactor on a 125 mixed reef. After my last media change, about a week later, I hit zero. Which was more like .06 probably and now two months later I'm at .19. So once a month is not necessary for me.
 
Let me correct myself, The Hanna meter runs 49.99 and the reagents (25pk) are 8.99 so your looking @ around 59.00 + shipping. I found this out when I went to order one yesterday. Sorry for any confusion about the price.
Bill
 
The Hach kit is very nice, and has been tested for reasonable accuracy. The Hanna meters are easy to read, and might be accurate enough.
 
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