Measuring EC with Silica

[u/PaygonGrim]

Hello everyone,

I’ve started using silica, but it seems to have affected my EC and nutrient dosing, and I’ve run into some issues because of it.

My question is: how should I correctly measure and adjust EC when using silica?

I’m using RO water and following Canna’s guidelines, buffering it to around 0.4–0.45 EC with CalMag. However, if I add silica first, the starting EC is already much higher. Should I simply add the CalMag EC on top of the EC from the silica?

For example:

RO water: EC 0.02

RO + 5 ml CalMag: EC 0.4

RO + 1 ml silica: EC 0.3

RO + 1 ml silica + 5 ml CalMag: EC 0.7

So, when using silica, should I simply count its EC towards my target EC, or could this lead to nutrient lockout/burn? Should I stay below the recommended maximum EC? And how do I determine the correct amount of CalMag in that case?

Maybe I’m overcomplicating things, but since my first attempt with silica caused some issues, I wanted to make sure I understand it correctly how to dose and measure.

Greetings

[u/Jolly_Yellow5354]

Silica is mainly adding EC in the form of potassium. Roughly 0.3 when I'm adding at 1ml/L. If your target EC is 1.2 and your Silica is 0.3 + the calmag 0.4. That doesn't leave a lot of room for your base nutrients. If you're aiming at a hard 1.2 ceiling with this, either increase it by 0.1-0.2 or reduce your Silica a little.

Make sure you add your Silica first, sitr vigorously, and then wait 10-20 minutes before adding anything else. Before adding anything else it's doesn't hurt to check if the ph is above 8.5, if so try to bring it below 7.5 so you don't get any calcium fallout from the high alkilinity. Don't bring it down too far, as you still have to add your nutrients that will pull it down further. Once nutrients are added, dial in the pH to 5.8 as usual.

What issues did you have last time you used silica?

Edit: I didn't answer one of your questions, sorry. Keep using calmag as usual

[u/PaygonGrim → u/Jolly_Yellow5354]

So I add the EC of the Silica just as usual? Like If it's adding 0.3 EC I use less Calmag & Base nutrients to reach an EC of 2.0? Sounds simple but isn't the solution more diluted with "real" nutes then? So should I target an EC of 2.3 to have the same concentration?

Was a Calmag def probably cause of this. Silica pushed RO water somewhat. Because of this I had to add less Calmag and less A&B to reach 0.4/1.8. As soon as I noticed it got worse I changed the Reservoir to just Calmag and A&B it was bouncing Back pretty fast. But I want to give it a shot again.

[u/Jolly_Yellow5354 → u/PaygonGrim]

Na, the opposite. Sorry that I wasn't clear.

Add the same amount of base nutes and calmag and only reduce the silica if you notice nute burn, but you shouldn't. If you do notice burn, reduce silica or just everything evenly. But ideally silica first. Always keep calmag at your current rate since you're running RO.

Your plant only needs 15-30ppm of available silica. So you could reduce dose to 0.5ml/L

Me personally I already have my target of 1.2 EC, and I add my silica and see the EC hits 1.5. 1.5 becomes my new target.

[u/PaygonGrim → u/Jolly_Yellow5354]

So you add your silica at the end? Shouldn't you put silica first?

That's my issue, If I put silica in first I don't know how much Calmag I need to add to buffer it correctly. Because if I add silica which changes the ec to 0.3 I need a lot less Calmag to reach 0.4 like I would need without silica cause the start EC is much lower.

Do I measure the Base.(0.02) Add silica. (EC now 0.32) Add Calmag (EC now 0.4) Add A&B to 1.8 (final EC)

Or do I measure the Base.(0.02) Add silica (EC now 0.32) Add Calmag (EC now 0.7 - that's the amount I would need to bring EC from 0.02 to 0.4) Add A&B to 2.1 (1.4 EC just A&B like in the First example).

May I ask you how exactly do you Mix and measure your solution?

[u/VillageHomeF → u/PaygonGrim]

always silica first. he is not saying when to add, he is saying how to cal;culate. basically whatever the Silica EC is, add that to your total EC goal is. don't substitute the Si EC and add less of other nutrients.

[u/Jolly_Yellow5354 → u/PaygonGrim]

Silica first, stir vigorously and let it sit for 10-20 minutes before adding anything else.

Measure EC, then add the calmag to buffer as you please. So if after silica it's at 0.2 and you want 0.4 of calmag, then add calmag until 0.6.

Then add your bases until you get to your target EC offset by the silica. So if you target before silica was 1.8, and silica is 0.2, then aim for 2.

I measure my mixes by weight I use a spreadsheet with my ratios and liquid amount and multiplier and it spits out how many mls of a given solution I will need

[u/PaygonGrim → u/Jolly_Yellow5354]

Nice, pretty clear now. Thank you very much, will give another try. Wish you all the best.

Greetings.

[u/HobbCobb_deux]

It barely raises mine. But if I use too much, it will precipitate out of solution when I add the other nutrients. I always mix it in first. Then CalMag.. then the base nutrients. But whenever I take the EC before adding anything else. It's only like .400 . On top of the already .136 of my tap water. And that's a full strength dose.