Phosphates - even with 0ppm TDS???

[JT101]

Is it possible to still have phosphates in your RO/DI water even if your TDS meter reads 0ppm?

The reason I ask is because I checked my RO/DI water last night with my Salifert test kit and I got about 0.03ppm. Since my HM Digital inline TDS meter read 0ppm I assumed there was a problem with it, so I checked the TDS meter with a calibration solution - it was perfect, well in cal.

Can anyone explain this, and, better still, how much phosphates are tolerable for LPS?

Thanks
John

 

[JimmyR1rider]

Only real way to assure you actually have 0 phosphates is with a photometer(hannah meter). Kits will read 0 yet you'll get the true reading from the meter or lab grade kits that we usually can't get.

All living things need some phosphates I was told by a speaker at one of the swaps that when he got them to read true 0 on his lab kits his tank actually suffered a bit, he brought it back to very minimal but present levels and it flourished again.

Again his minimal levels he talked about would never show up on a test kit at home, our phosphate kits really arent that accurate, as long as theyre reading 0 on your kits I'd say they're at an acceptable level.

 

[JT101]

Only real way to assure you actually have 0 phosphates is with a photometer(hannah meter). Kits will read 0 yet you'll get the true reading from the meter or lab grade kits that we usually can't get.

All living things need some phosphates I was told by a speaker at one of the swaps that when he got them to read true 0 on his lab kits his tank actually suffered a bit, he brought it back to very minimal but present levels and it flourished again.

Again his minimal levels he talked about would never show up on a test kit at home, our phosphate kits really arent that accurate, as long as theyre reading 0 on your kits I'd say they're at an acceptable level.

Hi,

Thanks for your reply. However, please note that I mentioned that I wasn't getting 0ppm on my kit - I got 0.03ppm.

In any case, I redid the test today. Guess what? I got 0ppm!! I then took another look at the instructions that came with the kit and they state that you should use "diffuse daylight" when doing the chart color comparison. Last night, I did the test by standard 100W incandescent lights in the living room where the tank is - today, there was plenty of daylight filtering in. I guess different lighting can affect how the colors come out.

Just for kicks I'm going to try it again tonight when it's dark out. I wouldn't be surprised to see another 0.03ppm reading, which will tell me to NEVER check my phosphates at night!

 

[mbg75]

Tds only reads conductive dissolved solids. So it might be possible. Good Tds info here.

http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.php

 

[JimmyR1rider]

Hi,

Thanks for your reply. However, please note that I mentioned that I wasn't getting 0ppm on my kit - I got 0.03ppm.

In any case, I redid the test today. Guess what? I got 0ppm!! I then took another look at the instructions that came with the kit and they state that you should use "diffuse daylight" when doing the chart color comparison. Last night, I did the test by standard 100W incandescent lights in the living room where the tank is - today, there was plenty of daylight filtering in. I guess different lighting can affect how the colors come out.

Just for kicks I'm going to try it again tonight when it's dark out. I wouldn't be surprised to see another 0.03ppm reading, which will tell me to NEVER check my phosphates at night!

Well thats good-- the reason I stated that even with 0 ppm on the test kit you'll still have some that the tests arent accurate enough to detect, just like you've found.

Was saying that as long as you keep the levels low enough that you don't have any register you should be good to go, if you start getting readings with a test kit, even if a minute amount means theyre are more than the test shows and you want to get them down to a level that the test won't detect.

Glad to hear your tests say 0 good deal and good luck with it from here on out.

 

[JT101]

Well thats good-- the reason I stated that even with 0 ppm on the test kit you'll still have some that the tests arent accurate enough to detect, just like you've found.

Was saying that as long as you keep the levels low enough that you don't have any register you should be good to go, if you start getting readings with a test kit, even if a minute amount means theyre are more than the test shows and you want to get them down to a level that the test won't detect.

Glad to hear your tests say 0 good deal and good luck with it from here on out.

Hey Jimmy,

Wow, I see you're local! Thanks again for the info.

John

 

[Josh]

Ask boomer, he'll know for sure.

 

[ecvernon]

I have the same thing happen.to me. Then I went to buy a 200 dollar hanna meter only to find out there is a +- 0.04 range in which it could be off....i just think there is no Sure way that our home kits can give us perfect measurements

Sent from my Samsung Galaxy Tab

 

[batt600]

It could be the container your using leaching po4. My RO-DI water is alway 0.000 Phos on my hanna

 

[ZANYMASTER]

Good point about the container.All containers must contain some kind of Po4's no matter what brand right?It's like when you put in frag racks,always get full of algae.

 

[JimmyR1rider]

Hey Jimmy,

Wow, I see you're local! Thanks again for the info.

John

Yeah we seem to be neighbors lol. No prob man- by no means an expert but been through the research phase about photometers and good point by ecv that even the meters have a give or take quotient.

Thats why I just got to the point of having good test kits(saliferts) and trust them if the test says 0 theres a small enough number of ppm to be acceptable.

Again best of luck.

 

[CraigBingman]

Is it possible to still have phosphates in your RO/DI water even if your TDS meter reads 0ppm?

The reason I ask is because I checked my RO/DI water last night with my Salifert test kit and I got about 0.03ppm. Since my HM Digital inline TDS meter read 0ppm I assumed there was a problem with it, so I checked the TDS meter with a calibration solution - it was perfect, well in cal.

Can anyone explain this, and, better still, how much phosphates are tolerable for LPS?

Thanks
John

John.... short answer is yes.

Longer answer is this.

1. 0 ppm TDS on your meter has some uncertainty to it. In actuality it is probably plus or minus a couple of ppm. Not a big issue at higher dissolved solids, but a big deal around the big zero.

2. TDS meters measure the effect of solutes (dissolved stuff) on the conductivity of water. Some ions have a larger effect than others. Phosphate is weakly ionized and has slightly less effect on conductivity than you would expect.

3. Test kits for phosphate aren't exactly perfect either. I haven't used the Hannah kit, but silicate interferes positively with some phosphate test kits. Silicate is even more weakly ionized than phosphate, even harder to remove than phosphate. (Even though I am a big fan of silicate.)

4. Phosphate is one of the first ions to start to break through a functionally exhausted bed of deionization resin. So it is quite possible for your purification rig to be removing almost everything from the water, except a bit of phosphate that is starting to be displaced by other incoming ions.

How much phosphate is tolerable to LPS? Well, phosphate should probably be undetectably low (or nearly so) with your Hannah test kit, in your system, for optimal coral health. There really isn't much if any difference in the inhibition of calcification by phosphate in "LPS" vs "SPS" corals. This is especially true because LPS and SPS are divisions of corals that have zero taxonomic or scientific validity. For this purpose all stony corals are the same.