How much sodium silicate to get 2ppm in 200mL?

[Miami Reef]

The Salifert test drawing a blank is puzzling:

1. Silicate to be dosed isn't what it claims to be?
2. Test kit is not working?
3. Type of Silicate isn't being detected?
4. Adding it to the tank causes it to immediately precipitate out?
5. Silicate binds to something immediately?
6. It's a freshwater and not saltwater test kit?

I'm going to try mixing RODI with known (probably) concentration high/low to test again.

Also mixed RODI and salt and repeating the test.

I'm also going to buy a bottle (not a LFS sample bottle) of the Silicate. Is Water Glass much more viscous than water? Perhaps I have was sold a placebo?

For now, with no way to dose and test I'm looking for guidance e.g. can you keep applying the recommended dosage of 2-4 ppm every few days? The Hanna Silicate Testers don't seem to be available to buy in UK - otherwise I would be tempted to get one.

If you read this thread, you would have known that the salifert silica test kit DOES NOT work.

Don‘t even worry about testing it. Just dose a known concentration once a week. That is plenty enough for diatoms and sponges.

 

[Simon_M]

If you read this thread, you would have known that the salifert silica test kit DOES NOT work.

Don‘t even worry about testing it. Just dose a known concentration once a week. That is plenty enough for diatoms and sponges.

Thanks very much. I will bring it up at my LFS. They sold me the product and the test kit - I will ask them why they pair them up - if it doesn't work. The product was only a small 10ml sample and I know I can buy it e.g. 500ml bottle for not much more.

So, if I don't test for silicate and simply dose for 2-3ppm addition once a week then that wouldn't harm anything and discourage dinos and promote diatoms?

I have been cleaning off my tanks's back wall. Has really bad hairy (dino) growth on it. Manual removal as well as treatment is the way to go?

LFS suggested not adding trace elements (for now) and having activated charcoal, not having UV on and (for now) not doing water changes. Good advice?

 

[Miami Reef]

LFS suggested not adding trace elements (for now) and having activated charcoal, not having UV on and (for now) not doing water changes. Good advice?

If you have a UV, use it. That will immensely help for most dinos we experience, especially ostreopsis.

Activated carbon is a good idea to remove toxins and organics.

You can stop water changes and trace elements until the dinos start receding. Then you can start again.

Dose about 1-2ppm of Si per week, and don’t worry about testing for it. It will decline fast; it won’t accumulate. If diatoms start getting annoying, scale back on the silica.

Ensure phosphates and nitrates are detectable. This is the correct approach for dinoflagellates.

Keep photoperiod to 8 hours max to encourage the dinos to enter the UV. Not all dinos will free swim, but most will. I wouldn’t bother with scraping the back glass: the UV will take care of them at night.

 

[taricha]

1. Silicate to be dosed isn't what it claims to be?
2. Test kit is not working?
3. Type of Silicate isn't being detected?

Right. It's number 2. Fortunately, seachem silica may work...

Received the seachem silica test and it's telling me 3-4 ppm which is about what I dosed.

So the salifert test for some reason is faulty as it still indicates zero.

 

[taricha]

Can I make a muriatic acid solution to clean my vials? Would that reset them to scratch? I want accurate results.

For many things, yes HCl is a good choice. But not all. I found that a slight blue stain in old cuvettes from running a bunch of po4 tests presumably, was not removed by acid. It was removed by a Clorox spray cleaner with some bleach in it. Many things may be removed by a good chemical soap like alcanox. There is no Universal cleaner for unknown contaminants, to my knowledge.
I've been able to make some stains on glass that are impervious to any cleaning treatment that I can come up with.

 

[Miami Reef]

@taricha

Can I ship you a bottle of my sodium silicate for you to do a quick test? I don‘t need a whole graph chart; just 1-2ppm Si and see what the phosphates show. You can keep the bottle of Si, too.

I want to know if the phosphate increase is real, or not.

 

[taricha]

I want to know if the phosphate increase is real, or not.

Sure. Sent you a message.

 

[Idech]

I want to know if the phosphate increase is real, or not.

I don’t have any tests to show for it, but IME there is no increase in phosphates.

I’ve been battling prorocentrum for 2 years and I’ve had to dose silicate at least 4 separate times. I don’t even bother testing phosphate anymore with the Hanna ULR as it‘s just faulty when dosing silicate.

How do I know it’s faulty ? I had an ICP test done and it showed 0.03 ppm while Hanna was showing 0.9 ppm.

 

[Randy Holmes-Farley]

Many things may be removed by a good chemical soap like alcanox. There is no Universal cleaner for unknown contaminants, to my knowledge.

Piranha solution can clean off any organic, but is very nasty and will akso decompose the cuvette.

Piranha solution - Wikipedia

en.m.wikipedia.org

“It is named after the piranha fish due to its tendency to rapidly dissolve and ’consume’ organic materials through vigorous chemical reactions.”

 

[Miami Reef]

I shipped my bottle of silicate to @taricha

He should receive it tomorrow.

 

[taricha]

Thanks to @Miami Reef for the bottle of water glass. Here's what I found with the Loudwolf water glass silica dosing....
(tldr: nothing much different than what @Rick Mathew and I have measured previously.)

first, the bottle is a mess inside. lots of white solids and some dark particles.

I ran it through a 1um filter because what's specified in the MSDS is supposed to be a liquid and the solids are certainly not what we want.
"Substance name : Sodium Silicate Solution
Concentration : 41%
Formula : Na2SiO3 + H2O
CAS No. : 6834-92-0, 7732-18-5
Product code : LW-WATERGLASS
Synonyms : Waterglass"

I added measured amounts of the liquid to 1L of tank water to make 0, 1, 3, and 4ppm SiO2 solutions. I was over 30% too high, then I realized I goofed and made stock by volume without looking at the density. Correcting with the MSDS info...
"Relative density : 1.39 g/cm3 at 25 °C (77 °F)"
The hanna SiO2 measured comes out right at what was expected. So the liquid portion is exactly what it should be in SiO2.

Here's what the hanna ULR P checker gives for the various concentrations between 0 and 5ppm SiO2.

Stock SiO2 expected (ppm SiO2)	hi736 ULR P reading (ppb P)
0	30
0	23
1.40	27
1.40	22
4.17	27
5.56	30
5.56	43
5.56	32

This fits decently well in context with what Rick and I have measured before....Yellow stars are the new measurements.

(Green points are Miamireef data from post 23 using the hi736, so a little different but not hugely.)

So a couple of points:
1) the SiO2 in the loudwolf product doesn't interfere with the hanna ULR P checker any more than the small amount documented previously with other Silica sources.
2) I'd advise if you get the loudwolf product to filter the tons of solid material off and discard, if you have syringe filters that'd be ideal, but probably running it through a couple of coffee filters a time or two will work.
3) use dedicated hanna cuvettes for each test kit. Hanna sells extras. Using a cuvette to go back and forth between different tests causes weird results sometimes, even with lots of washes between.

 

[Miami Reef]

Thank you so much, @taricha

The dirty sodium silicate was not my fault. I specifically opened a new bottle and used individual sealed syringes to take my samples. I didn’t filter it out when doing my experiments.

A few notes on my part:

1) I ordered a pack of 25 new hanna cuvettes. They don’t come with the caps. Can I use my current caps if they have been cross contaminated between my tests?

2) I will order the 1um nylon syringe filters and filter my silica.

3) I will reattempt the experiment once I receive the new tools.

4) Thank you so much, Taricha.

 

[Miami Reef]

@Randy Holmes-Farley

Is glass safe for transferring sodium silicate, or will the silica ruin the beaker?

 

[Randy Holmes-Farley]

@Randy Holmes-Farley

Is glass safe for transferring sodium silicate, or will the silica ruin the beaker?

Very high pH solutions can slowly etch glass, but short term exposure should be fine.

 

[taricha]

1) I ordered a pack of 25 new hanna cuvettes. They don’t come with the caps. Can I use my current caps if they have been cross contaminated between my tests?

hanna also sells caps, BTW.

 

[taricha]

oh, last thing to add just a bit of new info.
The Seachem Silicate kit will work well enough for some applications.
Below is the color result with the seachem kit compared to the numbers from the Hanna measurement for each sample.

I tried to match the camera setting to what my eye saw, but it looked a little more blue to the eye. In person, you'd say that 1.24 ppm SiO2 sample had noticeable slight blue, and the "zero" had none.

 

[Miami Reef]

hanna also sells caps, BTW.

I know, but is it needed?

 

[taricha]

I know, but is it needed?

Maybe. I would. (My caps stain more noticeably than my vials. So I can't rule out material transfer. )

 

[Miami Reef]

Maybe. I would. (My caps stain more noticeably than my vials. So I can't rule out material transfer. )

That’s what I thought. I ordered them already. I just wanted to ask.

 

[Miami Reef]

@taricha

I just opened a brand new bottle of loudwolf silicate (the same exact brand I sent you. It looks like someone spit inside of it. I see the same black specs, too!