Help with reading Salifert phosfate test and dosing question

[itelshot]

I have been dosing phosphate and nitrate into the tank for a month now. Nitrate is dosed easily, but phosphate - whether I can not normally distinguish by the color of the card and continue to dose 2 times more actively than nitrate or it is really absorbed somewhere, but where? (Low range test gives the same results). I do not have a lot of corals, they have not grown large yet.
To me, as shown in the photo, it seems today that the result is comparable to 0.03, doesn't it?

Quick setup:
1. Tank 185l + 40l sump (+- for all) 75x45x55 l.w.h.
2. Jebao Al-90 light
3.Two flow p. jebao mlw-20 (5k liters/h each work daytime)
4. Also filter socks, DIY cooler and scrubber, 25-27.5 degrees, salinity 0.026 +-, red sea salt. RODI water.

 

[jda]

I would say .03, or maybe a bit lower.

Is that one able to look through the side and divide the results by 10?

In the end, you have a trace. That is what matters.

 

[Snoopy 67]

I had so much trouble reading Salifert Phosphate kits I went digital with Milwaukee.
AND - For Low Range you should be looking through the side of the container.

 

[itelshot]

I would say .03, or maybe a bit lower.

Is that one able to look through the side and divide the results by 10?

In the end, you have a trace. That is what matters.

I'm thinking the same, at least i have a trace, but not clear water. The last question still opened - why it's so hard-rising. And no, side looking and 10 division is about nitrates. Here u must double water and reagents and divide by 2 with top look, but usually I don't want to waste test 2x faster.

 

[itelshot]

I had so much trouble reading Salifert Phosphate kits I went digital with Milwaukee.
AND - For Low Range you should be looking through the side of the container.

And no, side looking and 10 division is about nitrates. Here u must double water and reagents and divide by 2 with top look, but usually I don't want to waste test 2x faster.

 

[jda]

Most of the phosphate that you are doing is getting bound into the rocks and sand. po4 binds with aragonite to equilibrium with the water column.

If you have a trace, then your corals are not likely phosphorous deficient. There are more sources of phosphorous than just the one source of po4 that you can test for.

 

[hyprc]

In the case of po4, it really made things easier switching to Hanna's ULR Phosphate tester. I love Salifert but this test is just too hard to read imo if you're trying to keep lower levels of po4.

 

[itelshot]

Most of the phosphate that you are doing is getting bound into the rocks and sand. po4 binds with aragonite to equilibrium with the water column.

If you have a trace, then your corals are not likely phosphorous deficient. There are more sources of phosphorous than just the one source of po4 that you can test for.

Huh, got it. I'm not exactly new to marine tanks, but did you know some articles or literature where i can read about such detailed reef chemistry?

 

[itelshot]

In the case of po4, it really made things easier switching to Hanna's ULR Phosphate tester. I love Salifert but this test is just too hard to read imo if you're trying to keep lower levels of po4.

Heh, exactly! I thought that's something wrong with me

 

[jda]

Google Dr. RHFs article on phosphate. He details the binding in there. You can also search for threads on here - this gets discussed a LOT since most folks do not know that bind of po4 to aragonite happens.... like folks change large amounts of water and wonder why no3 went down, but not po4.

 

[jda]

Salifert is fine if you understand what po4 is and how phosphorous is used as a building block. It is fine to let you know if there is a trace, or a large amount. In the end, very few need to actually know what their number is unless you just cannot distinguish it from zero.