How long after dosing silicates is phophate testing reliable ?

[Idech]

I'm in the early stage of testing this out but I've been dosing 2 mls Na+ silicate daily for two weeks in my 150gal system, and while Hanna ULR results are running quite high, Hanna LR have been matching up with Nyos at much lower values. I get values of near 0.2 on the ULR when the other two are close to the zero values I've been struggling to raise for weeks.

Thank you, it’s good to read I’m not crazy, lol !

 

[taricha]

Are you saying I could buy the LR reagents and use them in my ULR checker ?

Taricha said that the ultra-low phosphorus kit uses the same reagent as the ultra-low phosphate.

Yes, that. But also it's possible, hanna has some packets that produce basically the same color but are meant to be read by different checkers.

But even if that doesn't work, at the very least you can see if the LR packets produce the expected low po4 color instead of the blue that you've been getting from the ulr packets.

Hard to believe that hanna has one specific po4 test that reacts much more sensitively to Si than their others, but apparently that's what people keep seeing. Guess I'm the crazy one with my old hi736.

 

[Miami Reef]

@Idech

Do you have any updates with the phosphate and silica interference/positive issue you had?

 

[Dan_P]

@Idech

Do you have any updates with the phosphate and silica interference/positive issue you had?

Try @Rick Mathew. I believe he has come to a conclusion.

 

[Miami Reef]

Try @Rick Mathew. I believe he has come to a conclusion.

Oh good. I use the phosphate ULR and I’m dosing silica (the silica tester is coming soon).

I noticed my phosphates are higher than usual, and the usual amount of GFO has no impact at all. It’s very strange and I highly suspect there is something wrong here.

To put in perspective, a quarter cup of high capacity GFO would tank .2 phosphates to about 0.05ppm-0.03ppm and it would stay there.

Now nothing is lowering the phosphates. I went through a shameful amount of GFO. I personally hypothesize there is something at play here. Hopefully we can get answers.

To put in perspective, my phosphates were about 0.01ppm for a few days. After dosing up to 1ppm silica, the phosphates jumped to 0.08ppm. A lot of GFO only brought it down to 0.04ppm. It’s unusual.

Of course, this is only anecdotal. I am not making any claims.

Disclaimer, I could be totally wrong about all my observations. I don‘t like saying my anecdotal experience because I don’t want to misinform anyone, but I am too curious and need help, so I can’t hold back anymore.

 

[Idech]

@Idech

Do you have any updates with the phosphate and silica interference/positive issue you had?

I’m still not able to use my Hanna ULR checker. There is still high levels of silica in the tank (I lost most of my fish and the dinos came back so I had to dose more silica). Even with lower levels, the checker was still not accurate.

I’m 100% sure this issue is real because once in a while someone else reports having the same problem with it while dosing silicate. I’ve seen a few dozen people talking about it, at least.

I don’t test anymore. I’ll do another ICP test soon and rely on that.

 

[Dan_P]

Oh good. I use the phosphate ULR and I’m dosing silica (the silica tester is coming soon).

I noticed my phosphates are higher than usual, and the usual amount of GFO has no impact at all. It’s very strange and I highly suspect there is something wrong here.

To put in perspective, a quarter cup of high capacity GFO would tank .2 phosphates to about 0.05ppm-0.03ppm and it would stay there.

Now nothing is lowering the phosphates. I went through a shameful amount of GFO. I personally hypothesize there is something at play here. Hopefully we can get answers.

To put in perspective, my phosphates were about 0.01ppm for a few days. After dosing up to 1ppm silica, the phosphates jumped to 0.08ppm. A lot of GFO only brought it down to 0.04ppm. It’s unusual.

Of course, this is only anecdotal. I am not making any claims.

Disclaimer, I could be totally wrong about all my observations. I don‘t like saying my anecdotal experience because I don’t want to misinform anyone, but I am too curious and need help, so I can’t hold back anymore.

I remember @taricha and @Rick Mathew remarking that gross overdosing silicate could interfere. How are you measuring the silicate concentration?

 

[Miami Reef]

I remember @taricha and @Rick Mathew remarking that gross overdosing silicate could interfere. How are you measuring the silicate concentration?

I am getting the Silica checker in the mail in 2 days. My latest dose I followed the calculation to add 1ppm from Randy’s article.

My silica goal is from .5-1ppm. It’s possible it might be higher. Not sure. I need to test it.

I might pick up the Red Sea Phosphate pro test kit as a backup.

 

[Dan_P]

I am getting the Silica checker in the mail in 2 days. My latest dose I followed the calculation to add 1ppm from Randy’s article.

OK that will be useful Information.

 

[Randy Holmes-Farley Verified Community Expert]

From taricha:

"Here's what Rick and I measured in 2020, it takes a whole lot of Si to make the hanna PO4 read too high to a degree that anyone should care about."

Why did my Phosphate plummet to 0.0?

Hi guys. Since the new year, my Phosphates have dropped from .05 to .00. The strange thing is, I am actively trying to raise it! Quick background: This is a 13.5g Nano and it was fishless and therefor not fed anything for about a year (except occasional reef roids for the zoas). Nitrates...

www.reef2reef.com

 

[taricha]

yep, Randy quoted the post with the most recent and thorough info.

The casual takeaway is that at high SiO2 (over a couple ppm), there's roughly a 1 in 100 interference. 1 part additional PO4 for each 100 parts SiO2. So 10ppm SiO2 gives +0.1 ppm PO4. This interference was similar regardless of which of the 3 various hanna PO4 packet chemistries used. (Thanks to @Rick Mathew )

 

[TWYOUNG]

yep, Randy quoted the post with the most recent and thorough info.

The casual takeaway is that at high SiO2 (over a couple ppm), there's roughly a 1 in 100 interference. 1 part additional PO4 for each 100 parts SiO2. So 10ppm SiO2 gives +0.1 ppm PO4. This interference was similar regardless of which of the 3 various hanna PO4 packet chemistries used. (Thanks to @Rick Mathew )

It may be anecdotal however my experience has been the LR checker has been accurate except at the peak of silicate dosing. ATI testing showed a 6000 microgram,(60 milligram), silicate level yet my tester has been consistently reading between 0.05 and 0.1. Applying the above "interference" factor would indicate my levels have actually been -0.01 to 0.04. Simultaneous testing with Nyos consistently yields results between 0.025 and 0.075, (i.e. a VERY light blue indicating the presence of a minimal amount of phosphate but less than the distinctly blue 0.1 reading.

 

[Miami Reef]

False alarm. All is well now.

 

[Randy Holmes-Farley Verified Community Expert]

False alarm. All is well now.

Looks good!

 

[Reef Puncher]

The data above in the Taricha post suggests this is not the explanation.

I know this is old but I myself am wondering when i can go back to hannah after stopping silicate dosing for Dinos.
I think its the light that hannah uses it must interact with the silicates somehow. My test results were showing around 0.4 phos when using hannah, but API and SERA test kits were showing about 0.2. So i am presuming silicates do affect hannah's ability even with Tarichas chart.

 

[Idech]

I know this is old but I myself am wondering when i can go back to hannah after stopping silicate dosing for Dinos.
I think its the light that hannah uses it must interact with the silicates somehow. My test results were showing around 0.4 phos when using hannah, but API and SERA test kits were showing about 0.2. So i am presuming silicates do affect hannah's ability even with Tarichas chart.

After you’ve done enough water changes to dilute the silicate. You just need to wait long enough for dinos to be gone and not come back.

It must have taken me 2-3 months.

 

[Reef Puncher]

After you’ve done enough water changes to dilute the silicate. You just need to wait long enough for dinos to be gone and not come back.

It must have taken me 2-3 months.

does silicate get eaten up? one person said diatoms consume it. another said silicate never goes away. another said it stays unless diatoms are in great enough number to use it. which i dont have many diatoms, they never really bloomed. some grew, but i never had a big bloom even after 2 months of dosing.

 

[Idech]

does silicate get eaten up? one person said diatoms consume it. another said silicate never goes away. another said it stays unless diatoms are in great enough number to use it. which i dont have many diatoms, they never really bloomed. some grew, but i never had a big bloom even after 2 months of dosing.

I can’t answer that.

Like you, I never had a diatom bloom. I figured the silicate would get eaten up but it seemed to never go away. It’s only when I felt secure enough to do WC that the Hanna test levels started to drop.

 

[Miami Reef]

After you’ve done enough water changes to dilute the silicate. You just need to wait long enough for dinos to be gone and not come back.

It must have taken me 2-3 months.

Please stop misinforming people with silicate and Hanna checkers.

Phosphate testing with the hanna checkers WILL be accurate as long as you maintain less than 2ppm silicate.

Idech, you made massive doses of silica (probably over 30ppm if I remember correctly?)

Diatoms will almost always rapidly deplete silicate. You can safely dose 1-2ppm a week for diatoms and still use the hanna checker.

 

[Idech]

Please stop misinforming people with silicate and Hanna checkers.

Phosphate testing with the hanna checkers WILL be accurate as long as you maintain less than 2ppm silicate.

Idech, you made massive doses of silica (probably over 30ppm if I remember correctly?)

Diatoms will almost always rapidly deplete silicate. You can safely dose 1-2ppm a week for diatoms and still use the hanna checker.

I’m sorry you view it that way but it’s not misinformation. I’m not the only one saying it, if I were, I would ‘t. You can regularly see people on FB reefing groups talking about it.

The fact of the matter is, since it’s not harmful for the reef, most people don’t test for silicate, so they have no way of knowing if they are above 2 ppm or not. And the Hannah checker gives them impossible readings.

I did dose a lot of silicate one time, a whole lot. The last time, I didn’t dose as much and still got funny results. I might have been over 2 ppm, I don’t know.

So next time I talk about, I’ll mention that 2 ppm limit. That’s all.