Silicate dosing?

[Randy Holmes-Farley Verified Community Expert]

just wanted to get back to you to say thank you for your help - have the dosing going now because of your kindness.

You’re welcome.

Let us know how it goes!

 

[Karliefish]

You’re welcome.

Let us know how it goes!

Hi Randy
It’s early days but corals are looking good. The dosing really does mess with the Hanna Phosphate checker. Any ideas on how to test for phosphates now?

 

[JakeH]

I have a few questions after reading about dosing water glass.

Is the effect on ph negligible when dosing sodium silicate?

Also, it was mentioned that the snow created is most likely magnesium hydroxide. Will dosing sodium silicate effect magnesium and alkalinity in any measurable way?

Will a solution stay sufficiently mixed in freshwater to auto dose over a period of time?

 

[Randy Holmes-Farley Verified Community Expert]

I have a few questions after reading about dosing water glass.

Is the effect on ph negligible when dosing sodium silicate?

Also, it was mentioned that the snow created is most likely magnesium hydroxide. Will dosing sodium silicate effect magnesium and alkalinity in any measurable way?

Will a solution stay sufficiently mixed in freshwater to auto dose over a period of time?

First, I'd buy a solution, not try to make it yourself. Solutions are readily available. They are totally stably unless you leave them open to the air to evaporate or absorb CO2.

The magnesium hydroxide that forms is the same that forms with all other high pH additives (which are mostly alkalinity additives). It will redissolve as it disperses, and will ultimately have no impact on magnesium or alkaliniyy, as long as you do not let it settle out in a pile where the local pH may be high and calcium carboante may precipitate.

Dosing silicate (which is a mix of different forms, but shown for one below, metasilicate) will very slowly boost alkalinity because you are adding silicate and organisms are precipitating silica, which leaves behind OH- which boosts alkalinity:

SiO3- - + H2O ---> SiO2 + 2OH-

This has more:

Silica In Reef Aquariums

Why would I recommend dosing silica? Largely because creatures in our tanks use it, the concentrations in our tanks (at least in mine) are below natural levels, and the sponges, mollusks, and diatoms may not be getting enough to thrive.

reefs.com

 

[Picassoclown]

Old post, I apologize, but I have water glass silicates and I am not sure if I am to first dilute it in a RO/DI solution, or add it straight to my system. I have a 210 gallon set up. In addition, I am using it to fight off a Dino outbreak. It was all over the glass, rock, sand, and sump. Currently, I have withered it away to just being on the sand and some on my live rock in my sump. It does not collect on the display tank live rock or glass any more. I am not sure how much to dose and if it should be a daily dose, or every other day. Any help would be appreciated. Thank you.

 

[Randy Holmes-Farley Verified Community Expert]

You can dose straight or dilute. In either case, but especially if dosed straight, you want to add to a very high flow area away from organisms due to rapid but temporary precipitation of magnesium hydroxide where it hits the water. You want to disperse that fast.

I dosed once or twice a week.

 

[Picassoclown]

You can dose straight or dilute. In either case, but especially if dosed straight, you want to add to a very high flow area away from organisms due to rapid but temporary precipitation of magnesium hydroxide where it hits the water. You want to disperse that fast.

I dosed once or twice a week.

Thank you Dr. Randy. Much appreciated, Sir.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you Dr. Randy. Much appreciated, Sir.

You're welcome.

Happy reefing.

 

[Picassoclown]

You're welcome.

Happy reefing.

I forgot to ask. Should my skimmer be shut off as well? Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

I forgot to ask. Should my skimmer be shut off as well? Thanks!

There's no need to shut off skimming as silicate cannot be skimmed out.

 

[Picassoclown]

There's no need to shut off skimming as silicate cannot be skimmed out.

Dr. Randy, I tried to message you, but can't .

I dosed as per your instructions earlier today with the water glass. I have a 210 gallon system and dosed 2ml, which should have measured 1ppm. I have the hanna high range silicate tester, could this be the problem as the reading is a bit too low? I thought it reads as low as 1ppm. Could it be that my tank used the silicates that fast? Should I increase the dose to 4ml tomorrow after a water change? You help is always appreciated. Thank you!

 

[Randy Holmes-Farley Verified Community Expert]

Dr. Randy, I tried to message you, but can't .

I dosed as per your instructions earlier today with the water glass. I have a 210 gallon system and dosed 2ml, which should have measured 1ppm. I have the hanna high range silicate tester, could this be the problem as the reading is a bit too low? I thought it reads as low as 1ppm. Could it be that my tank used the silicates that fast? Should I increase the dose to 4ml tomorrow after a water change? You help is always appreciated. Thank you!

How soon after dosing did you measure?

You detected none?

I might try making a standard by taking out some new or old tank water, measuring it, then adding a known amount of the silicate solution, and testing that a few min later.

 

[Picassoclown]

How soon after dosing did you measure?

You detected none?

I might try making a standard by taking out some new or old tank water, measuring it, then adding a known amount of the silicate solution, and testing that a few min later.

I measured about 5 to 6 hours later and detected 0. I will do a double dose. After reading your post I am not worried about adding in a bit more as there is really no target dose you can do. If this 4ml dose dose not measure tomorrow morning, than I will do a sample measurement like you said.

 

[Randy Holmes-Farley Verified Community Expert]

I measured about 5 to 6 hours later and detected 0. I will do a double dose. After reading your post I am not worried about adding in a bit more as there is really no target dose you can do. If this 4ml dose dose not measure tomorrow morning, than I will do a sample measurement like you said.

Sounds good.

Here's the rate of decline I observed:

Feature Article: Silica In Reef Aquariums ? Advanced Aquarist | Aquarist Magazine and Blog

Keep us updated.

 

[Incrediblegreen43]

Exact dosing is far from critical. Just dose a little less than I suggested above (reposted below) and it will be close to 1 ppm.

If you add 1.3 grams of this supplement (0.96 mL) to a tank with 100 gallons (378,500 mL), then the final concentration will be about 1 ppm SiO2.

Hi this is corry, what about a tank that is a 40gal?

 

[Randy Holmes-Farley Verified Community Expert]

Hi this is corry, what about a tank that is a 40gal?

For a 40 gallon tank instead of a 100 gallon tank, multiple the amount I recommend above by 0.4.

 

[Cscultho]

Has this method of adding silica been proven to beat Dino’s in the reef? I’m considering this method to battle my left over dinos after removing 90% of my sand bed.

 

[Righteous]

Has this method of adding silica been proven to beat Dino’s in the reef? I’m considering this method to battle my left over dinos after removing 90% of my sand bed.

I have had high silica throughout my tanks life. I have attributed it to the Tampa Bay live rock and sand I started the tank with (RODI is always zero).

My silicon typically measures 500μg/l. Even with those levels, I had to battle dinos once when nutrients plummeted. So by itself, silica dosing probably isn't going to do it.

I also have noted, that I primarily notice diatoms on my sand. When I did battle Dinos I had been running bare bottom. I can't say the two are definitely related, though I could postulate that for diatoms to outcompete the dinos, you may need the sand bed.

 

[Randy Holmes-Farley Verified Community Expert]

I have had high silica throughout my tanks life. I have attributed it to the Tampa Bay live rock and sand I started the tank with (RODI is always zero).

My silicon typically measures 500μg/l. Even with those levels, I had to battle dinos once when nutrients plummeted. So by itself, silica dosing probably isn't going to do it.

I also have noted, that I primarily notice diatoms on my sand. When I did battle Dinos I had been running bare bottom. I can't say the two are definitely related, though I could postulate that for diatoms to outcompete the dinos, you may need the sand bed.

Did you measure that 500 ppm Si by kit or icp?

Just an fyi, seeing Si in an icp does not necessarily mean silicate, and I’m somewhat skeptical that it is for folks who have substantial Si levels and do not see diatom growth. Perhaps some trace element is limiting then and not corals or algae, but since there are other Si molecules that might be in the water and which may not be usable by diatoms, I think that is a potentially viable explanation.

 

[Righteous]

Did you measure that 500 ppm Si by kit or icp?

Just an fyi, seeing Si in an icp does not necessarily mean silicate, and I’m somewhat skeptical that it is for folks who have substantial Si levels and do not see diatom growth. Perhaps some trace element is limiting then and not corals or algae, but since there are other Si molecules that might be in the water and which may not be usable by diatoms, I think that is a potentially viable explanation.

The 500μg/l (0.5ppm) is by ICP. Just remeasured it with my Hanna LR Silica (HI705) and it reports 110μg/l (0.11ppm).

I seem to have always had diatoms, along with that Silica number never changing. I notice you suggest dosing to 1ppm. Maybe its possible its not diatoms I have, and I should dose higher? I've just assumed that those levels were contributing to diatoms as brown dust on glass and sand.