# Anyone used the JBL SiO2 test?



## orxe87 (5 Apr 2021)

Has anyone used the JBL SiO2 test kit and got sensible results? 

I don't really like testing (either the philosophy or the practicality of it) preferring to see how things are doing with plants and fish as a better guide to water quality, but have a test kit just to be able to check if noticing something is out of balance. I was (very!) bored this evening so thought I'd test my tap water for SiO2, which is a test I've not used before. No diatoms left in my tank so I was expecting a low or zero result - it was just for fun(!) really. Surprisingly, it came back a deep, deep blue, which is nowhere along the yellow to dark green of the test chart for SiO2. I re-ran it three times thinking I'd made a mistake, but no, it's just simply not remotely in the correct colour spectrum. 

Anyone know if that test is susceptible to other things in the water, or to contamination somehow? Not really a problem either way, just curious if I have a duff test kit...

Thanks!


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## dw1305 (6 Apr 2021)

Hi all, 


orxe87 said:


> JBL SiO2 test ..........Surprisingly, it came back a deep, deep blue,


Probably a silly question, but might it be the low range phosphate test kit, rather than the silicate test kit? If it was it would account for the blue colour.

cheers Darrel


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## orxe87 (6 Apr 2021)

I wondered that, it's much closer. But three reagent bottles all mislabelled?

I was doing PO4 at the same time (which came back as zero), but it doesn't really match that chart's colours either, though much closer than the silicate chart. The SiO2 chart looks like it is heading towards blue at the end (it's kind of green-blue), so I guess it could be that I just have so much silicate that it is way off the scale... maybe I'll buy some RO water and see if I can find a silicate source to test the test kit!


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## sparkyweasel (6 Apr 2021)

orxe87 said:


> maybe I'll buy some RO water and see if I can find a silicate source to test the test kit!


You could dilute your tapwater with RO water and see how the kit reacts to the lower level.
You could also get a tapwater report to see what level you should expect.


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## orxe87 (6 Apr 2021)

Good idea. An excuse to go visit the LFS too...

(I have the water report, doesn't show silicates )


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## jaypeecee (6 Apr 2021)

orxe87 said:


> Surprisingly, it came back a deep, deep blue, which is nowhere along the yellow to dark green of the test chart for SiO2. I re-ran it three times thinking I'd made a mistake, but no, it's just simply not remotely in the correct colour spectrum.



Hi @orxe87,

I have never used the JBL SiO2 test kit but the chart below clearly shows a deep blue when SiO2 is high:









						JBL Silicate Test SiO2
					

Simple and reliable monitoring of water values. Determines silicic acid content when there are diatom problems in tanks




					www.jbl.de
				




JPC


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## orxe87 (6 Apr 2021)

It's a very different colour to anything on that chart - hopefully this shows it:



There's still mostly green in the right-most circle - it really isn't blue at all.


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## jaypeecee (6 Apr 2021)

Hi @orxe87 

On my PC monitor, the liquid sample in the vial has the best match with the right-most colour patch. In fact, it's a good match. But, it is best to set up the tubes as advised by JBL in the little booklet (and on the reverse side of the colour chart that JBL supply in the kit). That means that two vials are used, one of which is a "control". Take the caps off each of the vials and view from above.

If the reading is the highest value on the chart, it's important to dilute the tank water sample with RO or distilled water. Then multiply the resulting measurement by the dilution factor.

JPC


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## orxe87 (6 Apr 2021)

Hmm, not sure how else I can show how far off it is - it is really nowhere near a match, I promise! The >6 circle is a dark green, though with some blue. I do indeed use the method JBL specify, to the letter. I'm not colourblind, either 
Dilution with RO is the next step.

This is definitely only for curiosity - no issue with diatoms, no reason to think that SiO2 is causing any negative effect in the tank.


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## Wookii (7 Apr 2021)

orxe87 said:


> It's a very different colour to anything on that chart - hopefully this shows it:View attachment 166514
> There's still mostly green in the right-most circle - it really isn't blue at all.



Which patch are you referring to, the one on the far right (>6ppm)? If so, that is definitely a dark navy blue - very little if any green in it? I have the same JBL booklet here. 

I suspect your test water simply has way more than 6ppm silicates (if you are correctly using 10ml of sample water?), it’s a fairly low level by all accounts so I’m not sure why the JBL kit has that as a ceiling. I read that 5-25mg is the common range, and up to 100mg occurs frequently. 

As silicate levels have no bearing on anything in a planted tank, I’m not sure why JBL include it in their planted tank kit (other than the obvious profit motive).


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## John q (7 Apr 2021)

Wookii said:


> it’s a fairly low level by all accounts so I’m not sure why the JBL kit has that as a ceiling.


This could be one reason 🤔


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## jaypeecee (7 Apr 2021)

Wookii said:


> As silicate levels have no bearing on anything in a planted tank...


Hi @Wookii 

Although not specifically a _planted_ tank issue, it's surely related to the growth of diatoms. No?

JPC


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## orxe87 (7 Apr 2021)

Wookii said:


> Which patch are you referring to, the one on the far right (>6ppm)? If so, that is definitely a dark navy blue - very little if any green in it? I have the same JBL booklet here.


You're right - looking at it today under natural light it is more blue than green. I've just measured with a spectrophotometer to be sure - it has it as 'blackish blue', RGB 37 46 59, so very dark but also 25% more blue than green . I'm going to go measure the RGB of the kitchen LED lights next; hope it is that rather than my eyes... 

I'm still convinced the sample is a long, long way from that colour though. I'll repeat the test tonight and measure the sample colour too.


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## jaypeecee (7 Apr 2021)

orxe87 said:


> Hmm, not sure how else I can show how far off it is - it is really nowhere near a match, I promise! The >6 circle is a dark green, though with some blue. I do indeed use the method JBL specify, to the letter. I'm not colourblind, either...


Hi @orxe87 

One possibility for quantifying the colour on the JBL chart is to measure it. For this purpose, you could use an app such as _Color Picker_ for Android. I've suggested this app before on UKAPS - mostly for checking the spectrum of aquarium lighting. Just point your phone camera at the JBL colour patch and it will quantify that colour in terms of RGB plus other colour measurement systems. Try to do this in daylight as other lighting will skew the results. Many years ago, I had need to get my eyes tested for critical colour matching in the job I was doing at the time. It turned out that my eyes/brain were not seeing blue/green/yellow correctly. It literally opened my eyes! The following is worth a look:






						Types of Color Blindness | National Eye Institute
					

Different types of color blindness cause problems seeing different colors. Read about red-green color blindness, blue-yellow color blindness, and complete color blindness.




					www.nei.nih.gov
				




If I remember rightly, it turned out that I had slight blue-yellow colour blindness.

JPC


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## jaypeecee (7 Apr 2021)

orxe87 said:


> I've just measured with a spectrophotometer to be sure...


Hi @orxe87 

No sooner had I hit the 'Submit Reply' button a few minutes ago when I see you have access to a spectrophotometer. Please tell me more - either here in this thread or as a 'Conversation' if you prefer.

JPC


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## orxe87 (7 Apr 2021)

jaypeecee said:


> No sooner had I hit the 'Submit Reply' button a few minutes ago when I see you have access to a spectrophotometer. Please tell me more - either here in this thread or as a 'Conversation' if you prefer.


Ah, the joys of crossed posts - I nearly replied to your post before I realised you'd replied to your reply. Or something like that. I've sent a PM.

I'm annoyed at myself for discounting the effects of the kitchen LEDs on the colour patch, and also for not thinking of using the spectrophotometer earlier...


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## dw1305 (7 Apr 2021)

Hi all,


jaypeecee said:


> Although not specifically a _planted_ tank issue, it's surely related to the growth of diatoms. No?


I'm not sure you can directly relate the <"silicon (Si) content of the water directly with the growth of diatoms">. If you removed all the orthosilicic acid from the water column it would stop diatom growth, but it would have <"to be all of it">.

For me it is back to <"theoretically possible">, but all sorts of things eat diatoms, so we are somewhere near the best way to <"drink a glass of water">.

I don't noticeably have diatoms in any of my tanks, but I have <"Hornwort (_Ceratophyllum demersum_) in all the tanks">, which is also silicified, so I would be 99.9% sure that there is enough silicon to support diatom growth.

I'm much more interested in the <"probable compared to the possible">.


orxe87 said:


> I've just measured with a spectrophotometer to be sure...........it has it as 'blackish blue', RGB 37 46 59, so very dark but also 25% more blue than green .


Try @jaypeecee's suggestion of dilution with RO water.

cheers Darrel


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## Wookii (7 Apr 2021)

jaypeecee said:


> Hi @Wookii
> 
> Although not specifically a _planted_ tank issue, it's surely related to the growth of diatoms. No?
> 
> JPC



Covered far better by Darrel than I ever can, but in short, not really no, as evidenced by the fact that hundreds of tanks on this forum alone function with surely a wide range of silicate levels, and no noticeable diatom growth.

Also as Darrel suggests the level of silicate required for diatoms to grow is far below what we could ever hope to remove.

Ergo, the level of silicates in the water is irrelevant in a planted tank.


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## jaypeecee (7 Apr 2021)

dw1305 said:


> I'm not sure you can directly relate the <"silicon (Si) content of the water directly with the growth of diatoms">.


Hi @dw1305

It's rare that there is a simple cause -> effect relationship in lots of things, isn't it? I suspect that orthosilicic acid (H4SiO4) and other factors all play their part in the growth of diatoms whose hard frustule is comprised of SiO2. But, what is certain is that diatoms must obtain silicon (Si) from somewhere. Perhaps they obtain it from what they eat instead? If they can do this, that might - once and for all - eliminate tank water from the discussion?

JPC


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## sparkyweasel (7 Apr 2021)

orxe87 said:


> No diatoms left in my tank


(from op)
so a 'high' silicate test reading certainly doesn't mean diatoms are inevitable.


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## orxe87 (7 Apr 2021)

Only if this is a high reading, and not an anomolous one   Not proven yet.

Just tried to take a photospectrometer reading from the sample and failed - my kit just isn't set up for transmissive colours unfortunately. All I'll say again is that it is _very _different to the swatch - a pure deep sapphire blue. I'll hold off until I can get some RO and do a diluted test, hopefully this weekend.


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## jaypeecee (7 Apr 2021)

sparkyweasel said:


> ...so a 'high' silicate test reading certainly doesn't mean diatoms are inevitable.


Hi @sparkyweasel 

So true. And, I may have answered my own question concerning what diatoms eat. Silly me - they're photosynthetic creatures so they make their own food from a soup of elements, one of which has to be silicon. But, the $64,000 question is - where does that silicon come from?

JPC


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## dw1305 (7 Apr 2021)

Hi all,


jaypeecee said:


> But, what is certain is that diatoms must obtain silicon (Si) from somewhere.


They definitely get it from solution in the form of orthosilic acid. Apparently the exact mechanism, is fairly complex and has only been fully described recently.

Hildebrand, M _et al_ (2018) "Understanding Diatom Cell Wall Silicification—Moving Forward" _Front. Mar. Sci._, *5 *pp 125 says:


> ........ However, recent studies that monitor when components are made, and how they are transported to the silica deposition vesicle (SDV), indicate that investigation into the true dynamics of the process is possible. Real-time imaging and genetic manipulation offer the promise of elucidating the spatio-temporal dynamics of, and interactions between, components........Silicon dissolved in an aqueous solution at neutral pH is primarily in the form of silicic acid, Si(OH)4 (Iler, 1979). The solubility of a silicic acid solution is limited to around 2 mM, above that concentration silica (SiO2) begins to polymerize into polymers with a range of lengths, forming an amorphous solid (Iler, 1979; Kley et al., 2014)........ As a small, uncharged molecule, silicic acid can freely diffuse across membranes. Kinetic data indicate that, under environmentally relevant concentrations, diffusion can be the major mode of uptake (Thamatrakoln and Hildebrand, 2008). Under relatively low silicic acid concentrations, the silicon transporters (SITs) actively facilitate uptake.........





sparkyweasel said:


> (from op)
> so a 'high' silicate test reading certainly doesn't mean diatoms are inevitable.





orxe87 said:


> This is definitely only for curiosity - no issue with diatoms, no reason to think that SiO2 is causing any negative effect in the tank.


That would definitely be where I'm coming from. Diatoms are pretty <"much universal in liquid water"> (including melt water pools on glaciers, soil water, wet moss etc.) so I'm not sure where it comes from is really helps, the diatoms are there, so all liquid water must have enough silicon to support frustule construction. 


> ......Diatoms are found in all freshwater habitats, including standing and flowing waters, and planktonic and benthic habitats, and they can often dominate the microscopic flora. Because diatoms inhabit a broad array of habitats but many have specific habitat requirements, they have been used in freshwater environment assessment and to monitor long-term changes in ecological characteristics.......



cheers Darrel


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## jaypeecee (8 Apr 2021)

jaypeecee said:


> But, the $64,000 question is - where does that silicon come from?


Hi Everyone,

Well, the source of silicon is the tap/tank water - unless anyone can suggest an alternative/additional source. But, I've been digging into this somewhat deeper. It appears that there are three elements that are critical to the growth of diatoms, one being silicon. The other two are - not surprisingly, nitrogen and phosphorus.

"Phosphorus is seen as the nutrient that most likely to limit primary production in freshwaters"*.

"In many situations nitrogen may well be the limiting nutrient"*.

As most, if not all the research has been carried out on lakes and rivers, the classification of such waters typically ranges from oligotrophic to eutrophic. And, on this basis, the phosphorus concentration is from <0.015 to 0.055 mg/l (ppm). Converting this to phosphate figures (as measured by test kits), I make this a phosphate range from <0.05 to 0.17 mg/l (ppm).

Now some additional information:

"The ratio between Si and P, and the ratio between Si and N, determines which algae is (dominantly) present in the water. In natural waters, diatoms are often dominant in the spring (March-May). Their dominance is usually ended when all silicate is used and stored in the diatoms. When the diatom “bloom” collapses, it is often followed by the dominance of other (non-diatom) algae. The effects of an increased silicate concentration can be: - Shifts in algae species composition. Additional silicate will increase the Si/P and Si/N ratio in the water, thus creating conditions more favorable for diatoms; - Increased algae biomass. As mentioned, the development of diatoms in the spring is usually ended when silicate is depleted"**.

That's as far as I've got.

I'd like to make a personal request. If anyone is interested in trying to work together towards a _team_ solution on this topic, then please do so. I'm no more qualified than anyone else to solve the diatom outbreak problem. But, wouldn't it be nice if we could _collectively_ advance our knowledge of this topic?

* http://craticula.ncl.ac.uk/EADiatomKey/html/index.html  (unfortunately, this website right now appears to be out of action )

** Water quality information - What are silicates and why are they in water?  | APEC Water

JPC


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## dw1305 (8 Apr 2021)

Hi all, 


jaypeecee said:


> Well, the source of silicon is the tap/tank water - unless anyone can suggest an alternative/additional source.


I'd go further than that, it is any (and every) water source. 

It is the combination of persistent skeleton, the <"ubiquity of diatoms"> and <"their huge diversity">, that makes them useful as a <"trophic index">.  If they weren't so common they wouldn't be so useful. 

cheers Darrel


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## jaypeecee (8 Apr 2021)

orxe87 said:


> I'll hold off until I can get some RO and do a diluted test, hopefully this weekend.


Hi @orxe87

That will be interesting.

BTW, I hope you didn't mind the detour as to the factors leading to diatom outbreaks. Slapped wrist for me!

JPC


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## John q (9 Apr 2021)

jaypeecee said:


> "The ratio between Si and P, and the ratio between Si and N, determines which algae is (dominantly) present in the water.


Hi jpc, always interesting to read up on these subjects but I must admit a lot of the reading I did went over my head.
I think the article you first mentioned was referencing this paper.








						The influence of changes in nitrogen: silicon ratios on diatom growth dynamics
					

Nitrate loading to coastal waters has increased over recent decades while silicon loading has remained relatively constant or decreased. As the N:Si r…




					www.sciencedirect.com
				




I also found this article interesting in regards to people that have hypothesised for the last century over various limiting factors on phytoplankton growth, only for these to be later disproved.








						von Liebig's law of the minimum and plankton ecology (1899 1991)
					

The Law of the Minimum was originally formulated by Justus von Liebig, as one of the 50 interlinked laws concerned with agriculture. The original writings of J. von Liebig often were misinterpreted by his successors. BRANDT (1899) took this one law out of its context and proposed that limitation...




					ui.adsabs.harvard.edu
				



I've attached links to abstracts of the above articles and tried to add the full pdf files but not sure if I can upload these?

My understanding of the above articles for what it's worth makes me believe that if we are to create an environment that is beneficial to plant growth, then by default there will always be sufficient nutrition to feed diatoms and or algae.

Feel free to correct my understanding of the above.


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## orxe87 (9 Apr 2021)

jaypeecee said:


> BTW, I hope you didn't mind the detour as to the factors leading to diatom outbreaks. Slapped wrist for me!


Not at all, please keep at it.


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## dw1305 (9 Apr 2021)

Hi all, 


John q said:


> My understanding of the above articles for what it's worth makes me believe that if we are to create an environment that is beneficial to plant growth, then by default there will always be sufficient nutrition to feed diatoms and or algae.


I'd tend to agree with that. It is the "_plants you want ("Plants"_)" and "_plants you don't (Algae)_" argument, for me <"the bottom line"> is that <"they are all plants">.

cheers Darrel


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## jaypeecee (9 Apr 2021)

John q said:


> My understanding of the above articles for what it's worth makes me believe that if we are to create an environment that is beneficial to plant growth, then by default there will always be sufficient nutrition to feed diatoms and or algae.


Hi @John q 

You may well be correct. But, what if we could take advantage of the fact that diatoms, algae and cyanobacteria all obtain their nutrients from the water column whereas many/most plants can obtain most nutrients from the sediment/substrate? I say 'most nutrients' in the case of plants because they typically obtain carbon from CO2 injection or atmospheric CO2.

JPC


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## sparkyweasel (9 Apr 2021)

jaypeecee said:


> But, what if we could take advantage of the fact that diatoms, algae and cyanobacteria all obtain their nutrients from the water column whereas many/most plants can obtain most nutrients from the sediment/substrate?


That's something interesting to think about.
But won't the nutrients in the substrate dissolve into the water? Although the 'wanted plants' might get the lion's share due to having their roots right in the substrate, I think there will always be some leaching into the water column, and we know that the 'unwanted plants' don't seem to need a lot of nutrients to survive.


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## dw1305 (9 Apr 2021)

Hi all,


sparkyweasel said:


> But won't the nutrients in the substrate dissolve into the water? Although the 'wanted plants' might get the lion's share due to having their roots right in the substrate, I think there will always be some leaching into the water column


I think that is right. Plants can only take up nutrient as ions from solution and there must always be some interchange between substrate and water column.

The easiest "nutrient" to remove from the water column is light, if you don't get above LCP then you don't have any algae, but obviously that doesn't help us (or any-one else to be honest). After that my guess would be the next <"easiest is phosphorus (P)"> as <"PO4--- ions">, because of the wide range of <"insoluble phosphate compounds">, particularly in alkaline conditions.

It is likely to be a while before plants <"show phosphate deficiency">, even if you totally remove all PO4--- ions.

cheers Darrel


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## orxe87 (10 Apr 2021)

Managed to get some RO today (a whopping 14p a litre) so I've just been playing with RO dilution of the sample. I needed to take it down to 20% sample strength to get into the valid range for the test, so after multiplying back up that gave about 8.5mg/L Si02 in my tap water. (Control sample of 100% RO was 0mg/L). 

So, simply overrange on the test, then. 

I still maintain that the '>6' top colour swatch on the test chart bears no resemblance whatsoever to the colour of the sample...


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## jaypeecee (11 Apr 2021)

sparkyweasel said:


> Although the 'wanted plants' might get the lion's share due to having their roots right in the substrate, I think there will always be some leaching into the water column, and we know that the 'unwanted plants' don't seem to need a lot of nutrients to survive.


Hi @sparkyweasel 

Thanks for the feedback.

I agree with what you say 100%. But, we have a choice - take on the challenge or give up at the first hurdle. I'm not for giving up yet. I want to find out what's possible first. It's much more rewarding making improvements - no matter how small. And it's exciting making new discoveries. Darrel (@dw1305) has suggested taking a look at phosphorus/phosphate. Could this be a useful starting point? I also seem to recall that Diana Walstad is not in favour of adding iron to the water column - I'll check this.

JPC


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## jaypeecee (11 Apr 2021)

jaypeecee said:


> I also seem to recall that Diana Walstad is not in favour of adding iron to the water column - I'll check this.


Hi Folks,

In _Ecology of the Planted Aquarium_, Diana Walstad comments that "In my opinion, the substrate - not the water - is the best place to provide plants with iron".

JPC


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## sparkyweasel (11 Apr 2021)

Hi @jaypeecee , I know you won't give up  in your quest. 
On the subject of iron in the substrate, that was very 'fashionable' for want of a better word some years ago. Before the trend for fancy substrate, a layer of iron-rich material, such as laterite clay was popular, under inert sand or gravel.


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## jaypeecee (12 Apr 2021)

sparkyweasel said:


> Before the trend for fancy substrate, a layer of iron-rich material, such as laterite clay was popular, under inert sand or gravel.


Hi @sparkyweasel 

Many years ago, I used laterite myself but I'd have to try to find any notes I made at the time to see whether or not it was beneficial. I know that @dw1305 isn't a fan of laterite - comparing it to crushed house bricks or something like that. Darrel will correct me if I've got the wrong end of the stick.

JPC


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## dw1305 (12 Apr 2021)

Hi all, 


jaypeecee said:


> I know that @dw1305 isn't a fan of laterite - comparing it to crushed house bricks or something like that. Darrel will correct me if I've got the wrong end of the stick.


That is right, the brick and the laterite are red for exactly the same reason, it is the <"insoluble ferric oxides that cause the colour">.  Some very small proportion of that iron might become <"solubilised in anaerobic conditions">.

cheers Darrel


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## JanisF (12 Apr 2021)

I've used SiO2 from JBL. I bought it to test the water in our office tank and tap. It came back as >6pmm
I then asked for tap water samples to be taken to an independent lab for testing and as a matter of fact today I received the test results - our tap water SiO2 level at the time of testing was 8.5ppm.
So I guess the test was not wrong. Also I've used it at home on my RODI water and it came back as <0.1ppm.


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## jaypeecee (12 Apr 2021)

dw1305 said:


> After that my guess would be the next <"easiest is phosphorus (P)"> as <"PO4--- ions">, because of the wide range of <"insoluble phosphate compounds">, particularly in alkaline conditions.
> 
> It is likely to be a while before plants <"show phosphate deficiency">, even if you totally remove all PO4--- ions.


Hi @dw1305

You may recall that I recently had a phosphate deficiency in one of my tanks. It manifested as Frogbit turning very pale and dying off but it took me a few days to recognize that phosphate was very low. I was testing the tank water one day - only to find that phosphate was <0.02 mg/l (ppm). In the water sample that I recently had analyzed using ICP-MS, _phosphorus_ measured 19 micrograms/litre. I make this 0.06 mg/l (ppm) phosphate in round numbers. Unfortunately, the Frogbit died off but the Java Ferns are thriving on this level of phosphate.

Out of interest, why does it take "a while" before plants show a phosphate deficiency? Is this because aquarium plants can store a reserve of phosphate?

JPC


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## dw1305 (12 Apr 2021)

Hi all,


jaypeecee said:


> does it take "a while" before plants show a phosphate deficiency? Is this because aquarium plants can store a reserve of phosphate?


It is a combination of factors. Phosphorus is highly mobile within the plant, so the plant can continually shuffle it to the newer leaves. There is also  the possibility that PO4--- may become available within the substrate from "insoluble" reserves. How large that reserve would be dependent <"upon various parameters">.

cheers Darrel


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