Testing for phosphates

[saullman]

I don't understand why I keep getting 0 readings with my salifert test kit, but when I go to my lfs they get a high phosphate reading using an api test kit. I checked the expiration date on the packaging and it's good. Besides the Hanna checker which I can't afford right now I was told that salifert makes a good test kit, but could have fooled me.

 

[Saintnovakai]

I don't understand why I keep getting 0 readings with my salifert test kit, but when I go to my lfs they get a high phosphate reading using an api test kit. I checked the expiration date on the packaging and it's good. Besides the Hanna checker which I can't afford right now I was told that salifert makes a good test kit, but could have fooled me.

Buy a used Hannah off eBay. They often times go for $30 or less, if it can be squeezed into your budget, if you win the bid. You could also maybe ask a local reefer with one to test for you. I don't trust API. First things first. Are you seeing tell tale signs of high phosphate? Testing is the number 1 way to determine where you're at but many boss level reefers can look at their tank and tell you levels based on what they see.

 

[Ron Reefman]

I'd be more inclined to trust your Salifert test than an LFS using API test kit.

As Saintnovakai asked, are you seeing anything else wrong in the tank? Any algae growth starting? Do you have a refugium or ATS?

 

[saullman]

Buy a used Hannah off eBay. They often times go for $30 or less, if it can be squeezed into your budget, if you win the bid. You could also maybe ask a local reefer with one to test for you. I don't trust API. First things first. Are you seeing tell tale signs of high phosphate? Testing is the number 1 way to determine where you're at but many boss level reefers can look at their tank and tell you levels based on what they see.

Yes, I have been dealing with gha issues for months now. I am just starting to get it under control, but it would be nice to know what my phosphates are. My salifert test kit has NEVER given me any kind of reading since day 1.

 

[saullman]

I'd be more inclined to trust your Salifert test than an LFS using API test kit.

As Saintnovakai asked, are you seeing anything else wrong in the tank? Any algae growth starting? Do you have a refugium or ATS?

Yes, I have gha problems. It is a JBJ 45 gal AIO tank. I do not have a refugium. Not sure what an ATS is?

 

[saullman]

Also I have been looking at the Hanna test kits. If I were to buy 1, I'm not sure which one I should get. They have a phosphorus, phosphate, and a phosphate ULR.

 

[link81]

Not sure what an ATS is

algae turf scrubber

chances are the GHA is consuming the po4 as fast as it's created. I would also trust any kit over the API. although if you have zero color whatsoever, then po4 is most likely pretty low.
I ended up getting a hanna phosphorus checker, it reads much lower then a color change kit. (i try to maintain about 0.1ppm)
what are your nitrates? light source? photoperiod?

 

[link81]

@saullman
this one:

https://www.bulkreefsupply.com/phos...eter-hi736-hanna-checker-hc-marine-water.html

https://www.reef2reef.com/threads/which-hanna-phosphate-checker.585482/

 

[Saintnovakai]

Man although everyone says get the Phosphorous checker I really am not convinced I need one. I don't want levels that low anyway. 0.02-0.08 is my wiggle room. Any lower or higher than that for someone new to reefing is asking for trouble. Also you may never find a Phosphorous Hannah used on eBay. That's a looooong shot.

 

[infinite0180]

I have the hi774 and it works very nice...

 

[saullman]

algae turf scrubber

chances are the GHA is consuming the po4 as fast as it's created. I would also trust any kit over the API. although if you have zero color whatsoever, then po4 is most likely pretty low.
I ended up getting a hanna phosphorus checker, it reads much lower then a color change kit. (i try to maintain about 0.1ppm)
what are your nitrates? light source? photoperiod?

API tested 1-2 ppm phosphates
Nitrates are 0.
Light source is AI Prime HD
Photo period is 9 hours

 

[link81]

my guess is that the API kit is wrong, and you actually have zero no3 and po4 (or very close to zero)
the GHA is most likely consuming it before you get a chance to measure anything.
try shortening your photo period and manually remove as much as possible. you want the nutrients in the water column so you can measure them and find out what you actually have.

what do you have for corals? you can also try a total blackout for a couple days along with manual removal.
read up on some of the GHA threads here regarding different removal techniques.

 

[saullman]

my guess is that the API kit is wrong, and you actually have zero no3 and po4 (or very close to zero)
the GHA is most likely consuming it before you get a chance to measure anything.
try shortening your photo period and manually remove as much as possible. you want the nutrients in the water column so you can measure them and find out what you actually have.

what do you have for corals? you can also try a total blackout for a couple days along with manual removal.
read up on some of the GHA threads here regarding different removal techniques.

Right now the tank looks pretty clean. I manually removed what I could and also used a toothbrush on everything else.

As far as corals go I have LPS and softies.
Zoa's, mushroom, hammer, Duncan.
They are not happy with me right now.

 

[Bayareareefer18]

I use the low range hannah. I feel it's accurate enough for what I doing with an LPS dominant tank. If I were going full blown sps that might warrant the ULR.

Sure a .03 might be a 0 or .06 but I feel that gives me enough insight into what's going on with my tank. Very easy test to use, IMO, once you get a feel for the process.

 

[AZRipp]

You need something to out-compete the GHA for nutrients, primarily Phosphate. This can be done with a refugium and some form of macro algae, an Algae Turf Scrubber (ATS), or through some form of media, such as Granulated Ferric Oxide (GFO). Your goal is to get something else to consume the phosphates, to include what is leaching from your rock, before the GHA can get it. This in turn will starve the GHA out of existence. Once you have it under control, you will then need to monitor for phosphates so that you don't get an imbalance, primarily between Nitrates and Phosphates. A good spot to shoot for in Phosphate is around .03 PPM.

 

[dbjonesjr]

I have both the Hanna and the Salifert test kits. I always read the Salifert to be less than the actual value (it's difficult to read the test at low values in my opinion) the Hanna gives me. After using the Salifert for about two weeks I got annoyed and got a Hanna.. However, if you have GHA then you clearly have a nutrient problem; no doubt about that. What kind of nitrates do you have? If you have high enough nitrates you could try carbon dosing to get nutrients down. Anyways, I rarely test for phosphates anymore as the algae and coral health typically gives me better information than the test kits do.

 

[PatW]

I would suggest getting the Hanna ULR test. It is the most sensitive hobby phosphate test kit available. And even with ULR, it still reads high enough for practical usage. And something like 90% of the range of the test is higher than the .03 ppm generally recommended.

 

[saullman]

I have both the Hanna and the Salifert test kits. I always read the Salifert to be less than the actual value (it's difficult to read the test at low values in my opinion) the Hanna gives me. After using the Salifert for about two weeks I got annoyed and got a Hanna.. However, if you have GHA then you clearly have a nutrient problem; no doubt about that. What kind of nitrates do you have? If you have high enough nitrates you could try carbon dosing to get nutrients down. Anyways, I rarely test for phosphates anymore as the algae and coral health typically gives me better information than the test kits do.

I have 0 nitrates according to API.

 

[jim_fitz]

its really difficult to find any reference levels for phosphorus (total P) in a reef tank
there is little info out there and that i trust
so i would recommend focusing on measuring phosphate - this is assuming you are looking at getting a hanna checker which id highly recommend

i use salifert for nitrate - do you need to look down on the sample ? might make a subtle difference

 

[Dan_P]

I don't understand why I keep getting 0 readings with my salifert test kit, but when I go to my lfs they get a high phosphate reading using an api test kit. I checked the expiration date on the packaging and it's good. Besides the Hanna checker which I can't afford right now I was told that salifert makes a good test kit, but could have fooled me.

There is the possibility that test reagents are bad. How old is the kit?