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MSA Info
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MSA Info
Been seeing more talk about monosilicic acid (MSA) lately, especially after Scotty and the DGC crew touched on it. I’ve been playing with MSA for quite some time before most where talking about it. But now I feel more comfortable sharing my input. I brought this up in another post a bit ago, but figured I’d repost it here in the proper category to go more in-depth and hopefully reach the growers who want to dive into this stuff instead of digging through my timeline.
I’ve been actively using MSA in my grow—specifically Grow Genius—and I’ve learned quite a bit about how it behaves, how it plays with salt-based nutrients, and how it affects pH and plant structure when used correctly.
This post isn’t about hype—it’s about real-world performance, consistency, and how to avoid messing it up by treating it like just another additive.
I do hope this helps anyone out there who’s struggling to use MSA or is thinking about incorporating it into their grow. This information is based specifically on my experience using it in soil with salt-based nutrients from General Hydroponics, Botanicare, and Recharge from Real Growers.
Are you feeling the effects of slowly falling pH and cloudy mixes after a short period of time with using MSA? This is actually a common but misunderstood reaction when mixing and storing nutrient solutions, especially with mono-silicic acid (MSA) in the mix.
Here’s exactly what is causing your mixs to turned cloudy and acidic over time, even though it was clear and stable at first.
1. MSA is highly reactive and unstable in solution over time. Regardless of what people say, it really is.
• Mono-silicic acid starts polymerizing (bonding with itself and other elements) when left sitting in water, especially in salt solutions.
• This creates larger silica chains and insoluble silicates, which is what causes the cloudiness—that’s precipitate forming, meaning certain elements are no longer in usable form.
2. pH drift is natural in stored nutrient solutions with MSA
• Over time, certain ions continue to interact—especially calcium, magnesium, iron, phosphates, and silicates.
• These interactions can lower the buffering power of the mix and cause the pH to steadily fall, even if it was perfectly dialed when fresh.
• MSA is acidic by nature (even though it doesn’t affect pH at first), and once it starts breaking down and reacting with other compounds, thats when it becomes more acidic, tipping the pH scale further down.
3. Dissolved oxygen depletion and stagnation
• Letting nutrient water sit for days without aeration can cause dissolved oxygen to drop, especially if it was warm or sealed tight.
• This can change the chemical behavior of nutrients and make the solution more acidic over time.
• Stagnant solutions also promote minor microbial or chemical activity that subtly shifts pH, especially with sugar-based additives or trace organics.
So, what to do about it?
Best Practice with MSA in Salt-Based Mixes:
Mix only what you plan to use within 12 hours if MSA is included. If you’re not feeding right away, the better approach is to pre-mix your nutrients without MSA or pH adjustment. This gives you a stable base solution that you can finish off later.
On the day of feeding—ideally within an hour of use—take your stored solution, add your MSA first, then adjust pH, and finally add Recharge if you’re using it. Mix it thoroughly, then feed immediately.
Never add MSA or Recharge to a solution and let it sit for hours or days. That’s a fast track to instability, pH drift, and nutrient precipitation. Keep it clean and fresh, and your plants will thank you.
• Always add MSA before pH, mix well, then pH.
• If you must store it longer, keep it cool, oxygenated, and sealed, but expect pH and clarity shifts. I recommend only making the nutrient solution when you need it.
• Recheck and adjust pH right before feeding, and discard cloudy mix if you see heavy precipitate—it means certain nutrients are no longer available.
Bottom Line:
Your mix was good when it was clear and fresh, but after 24+ hours, natural chemistry will take over. The MSA will likely reacted with other elements and degraded, lowering pH and making the solution cloudy.
If it were me? I’d discard the old mix and remix fresh to ensure full nutrient availability. You’re better off giving them something clean and reactive than something partially bound and drifting.
Also MSA can absolutely contribute to a gradual drop in soil pH. When you mix MSA fresh right before feeding, it doesn’t have enough time to chemically interact with the rest of the nutrient salts or the water chemistry and shift things significantly. It gets delivered into the soil in a state that’s ready to be absorbed, used, or buffered by the medium before it starts messing with stability.
Now, when you’re in a buffered medium like Coast of Maine Stonington / Fox Farm Ocean Forest and or Happy Frog you’re feeding at reasonable EC and pH (6.3-ish), a properly timed and dosed MSA hit won’t cause a meaningful long-term pH shift in the soil—especially if you’re not soaking the hell out of the root zone every time. I also recommend on using MSA from seedling to early bloom. Once you’re out of stretch that is when you should just stop using it in general.
So to break it down:
Yes, MSA lowers the solution pH the longer it sits, especially if it’s interacting with salt-based nutrients.
No, it won’t drop soil pH meaningfully if used correctly—freshly mixed, properly pH’d, applied right away.
Overuse or high frequency with poor buffering or low runoff could absolutely cause acidification over time.
If you’re still seeing soil pH drop over time, the culprit is more likely the cumulative salt buildup, not from MSA.
Optimal Mixing Order
*mix well between each add – I use an electric water pump to mix*
RO Water
3 Part GHP Micro → Grow → Bloom
CalMag (if used)
Sweet Raw or Epsom Salt (if used)
MicroGenics .75% – trace micros (if used)
MSA Grow Genius
pH adjust after MSA.
Recharge enzymes aminos go in last after pH and inputted into the plants right away, do not let it sit.
Why I Use Mono-Silicic Acid (MSA) Instead of Potassium Silicate versions?
MSA is the most bioavailable form of silicon you can give your plants. Unlike potassium silicate products, it doesn’t need to be broken down by microbes or converted by the soil. It’s immediately plant-available—and that changes everything in a controlled grow. No more double duty for your microbes.
It Doesn’t Affect Potassium Ratios
Potassium silicate adds extra potassium to your feed, which throws off the balance of your nutrient ratios. With MSA, you don’t have to recalculate your PK levels or worry about stacking too much K—your ratios stay clean and lean.
No Soil or Microbial Conversion Needed
Potassium silicate requires microbial life to break it down before it becomes available to the plant. MSA skips that step entirely. It’s already in the mono form that roots can take up directly. That’s less stress on the soil and no reliance on breakdown timing. Keeps a better buffer zone.
Fast and Predictable Results
MSA is absorbed quickly, leading to faster structural responses—stronger stems, tighter node spacing, thicker cell walls. You actually see the benefits instead of waiting and guessing.
Compatible with Salt-Based Systems
MSA doesn’t raise pH (unless you let it sit in a solution for a long time) like potassium silicate does, and it won’t cause precipitation when added properly. That makes it ideal for salt-based nutrient regimens where stability and clarity matter.
Lower Usage Rate
MSA is used at very low concentrations (often 0.1 – 0.4ml/gal), so it’s highly efficient per gallon compared to bulky potassium silicate products. Less in, more results.
Boosted Resistance to Mold, Mildew, and Pests
Silicon strengthens the outer cell walls of the plant, making them tougher and less penetrable. This helps the plant naturally defend itself against powdery mildew, botrytis, spider mites, thrips, and other common threats. It’s not a pesticide—it’s structural immunity from the inside out.
Great for Seedling, Transplants, Veg
Because it’s bioavailable instantly, it helps young plants build stronger structure and faster root development right from the start.
Can Be Used as a Foliar Spray
Mono-silicic acid can be used as a low-dose foliar spray, which makes it one of the most versatile silicon products available. Unlike potassium silicate, which is too alkaline and can cause leaf damage when sprayed, MSA absorbs directly through the leaf surface without burning or raising pH too much.
It’s especially useful during:
Early veg, for boosting cell strength and structure
Stress recovery, to reinforce plant defenses quickly
Cloning or transplant shock, where root uptake may be limited
When used as a foliar, MSA delivers fast structural reinforcement and improved resistance to pests, mildew, and stress—right through the leaf tissue.
I really wish the manufacturers of MSA products would just come out and say this directly—but they don’t. Most of them claim you can mix it in any time and in any order, but the reality is: you technically can, but you really shouldn’t.
It took me a few days of observation and trial and error to fully dial this in. And the truth is, a lot of growers wouldn’t catch it, especially if they’re not deeply in tune with nutrient chemistry. They’d just notice cloudy mixes, unstable pH, or inconsistent results and not realize MSA was the issue.
That’s why I’m sharing this—to help others avoid wasting product or unknowingly stressing their plants. If I can save someone else the hassle of figuring this out the hard way, it’s worth the post
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3 Replies
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Quick note for those using MSA during the stretch phase—especially on plants with aggressive vertical growth (3–5x their veg size):
Be mindful not to overdo it.
MSA strengthens cell walls and increases rigidity in plant tissue. That’s great for building strong structure and tighter internodes—but if you apply too much during early flower, especially on stretchy cultivars, it can actually suppress vertical growth.
This means:
- You may limit the plant’s natural stretch more than intended
- The plant will respond by becoming bulkier and stockier
- Helpful for indoor cultivations
So if you’re working with stretchy genetics, dial MSA in light and precise during transition. Let the plant do its thing, then bring in more consistent doses after stretch to lock in structure and support heavy flower sites.
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Also another tip
When mixing MSA into your solution, do not let any water or nutrient residue get back into the MSA container-it will start breaking it down and render it unusable. Be extremely mindful of whatever tool you’re using (like a dropper or syringe). Once it touches your solution, don’t dip it back into the MSA bottle unless it’s completely clean and dry.
Cross-contamination will ruin the integrity of the product.
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Here’s a run of Chicken and Waffles from Humboldt Seed Company that I germinated from seed. These two are being trained and built up to become full-blown monsters, and if things stay on track, I’m expecting a 2–3 lb yield out of this 4×4—right in line with what I usually pull when running two phenos like this with a solid veg cycle and proper staging.
They’re just starting Week 4 of veg. Up to this point, they’ve mostly been fed plain RO water with monosilicic acid (MSA) added in. That alone has helped them develop thick, resilient stalks and tight internodes. The soil has been doing its job as a great buffer, keeping things balanced. I’ve recently started introducing salt-based nutrients at a low dose, and these girls are about ready to flip into flower soon.
Let’s see what these beasts can really do.
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