Sodium Silicate dosing calculation

[hawkinsrgk]

I am having trouble trying to determine the correct amount.

I have Sodium Silicate 40% solution and would like to add this to a gallon of RO water so that when I dose 10ml of this solution to 360 gallons of tank water it will add 0.1 ppm Silica.

Thanks for the help
Randy

 

[hawkinsrgk]

I think the answer is add 72.8ml of sodium silicate in 1 Gallon RO water and 10ml of this will add 0.1ml Silica to 360 gallons of tank water.

 

[JimWelsh]

The answer I get is 400 mL of 40% sodium silicate solution diluted to 1 gallon will increase the Si content of a 360 gallon tank by 0.1 mg/L when 10 mL of the diluted solution is added to the tank.

Here's how I got there:

Your 360 gallon tank is 360 * 3.785 = 1362.6 liters. To increase the Si in that volume by 0.1 mg/L will require 0.136 g of Si. Since you want 10 mL of diluted stock solution to accomplish this, then the stock solution needs to have 0.0136 g/mL of Si, or 0.0136 * 3785 = 51.5 g / gallon of Si. Sodium silicate is only 23% Si (MW of sodium silicate = 122.06, and atomic mass of Si is 28.0855, so 28.0855 / 122.60 = 23.01%), so we will need 51.5 / 0.23 = 224 g of sodium silicate per gallon. Your solution is 40% by weight, so we will need 224 / 0.4 = 560 g of solution, but this solution has a density of about 1.4, so that means 560 / 1.4 = 400 mL.

I hope this makes sense.

 

[hawkinsrgk]

Thank you so much Jim. It makes since. I seriously screwed that one up.

 

[Leland Foley]

What test kit are you using to test for silicate? I heard the salifert is hard to read. I had a triton icp test done, and my silicates are low so of like to add some, but don't know how to monitor how much is being consumed.

 

[hawkinsrgk]

I'm just getting everything setup to start doing this. I read Randy's article and he suggests one by Hach. From what I remember it's almost $120. Think what I'm going to do is get the salifert one and if that doesn't work I'm only out $16. From Randy's article it seems to get consumed quite quickly. My main reason for all of this is a food source for a conch and some snails. I removed my sandbed a while back and I'm afraid they are not getting enough food

 

[Randy Holmes-Farley Verified Community Expert]

Yes, it is consumed quickly, and IMO, most folks can dose a NSW level once a week (or the same amount spread out) without concern for overdosing.

 

[hawkinsrgk]

Thank you Randy for the confirmation and feedback

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Good luck!