And probably asked a hundred times before, but I cant seem to find a specific answer to fit my situation. I’m growing in a 7 bucket, 25 gallon sterile RDWC that I maintain at 67 degrees f. So with that said, what do you use to bump your TDS numbers up throughout the week, or do you adjust at all?
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More nutes - higher dosing. TDS is a direct measurement of the nutrient concentration in your water.
If your TDS is dropping that means you can up your solution concentration. If your TDS is rising you lower the solution concentration.
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yup thats my question, what do you bump it up with?
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Just mix a stronger nutrient load. If your TDS is at 900 and drops to 600 then mix nutes to bring to 1,100 or so. If it drops again, bump it up a bit more.
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I only mix my nutes once a week, but as my plants eat throughout the week I try not to let the TDS drop below the minimum level for their growth stage. I’ve been using calmag because I thought that was the proper use for it, but I keep teetering on nitro burn and calmag is all I’m supplementing with. so I was wanting to see what everyone else supplements throughout the week with. So should I mix more than I need and just use that to bump up with that ?
Just mix normal ratio of nutrient solution, only stronger.
CalMag shouldn’t be added to an existing solution, it’s always added first from what I’ve seen (after silica).
yup, thats how I mix my 25 gallon weekly batch. Armor-si 1st then cal mag then the normal suspects, but I thought that folx were using calmag throughout the week to replace what TDS the plants are eating. My bad. I should really watch my assumptions lol.
I actually did find a site that said to add calmag last lol.
Unfortunately TDS doesn’t differentiate. There’s really no telling which specific nutes plants are taking more of, which is why a dump and refill are needed occasionally, to reset any nutrient imbalances. Ratios are important, or lockout of some nutes can occur, so when topping up I mix the exact same ratio as the initial feed (as long as it’s working) but just stronger to up the overall TDS. Then the next batch I might make it a little stronger, since the plants are eating more than they’re drinking.
Last? interesting. There’s lots of fertilizer companies out there, so no telling what they’re using. “Generally” it’s always first, and mostly for people with RO/distilled/rain water.
What is the reason for a mixing order? I’ve never paid attention to the mixing order of nutrients.
Lockout mostly. Some fallout. Just chemical reactions. Like how Jacks has you add the epsom before the calcium. Then some use anhydrous chems, then some hydrate ones don’t mix well… lots of chemistry I don’t fully understand. Much probably depends on the makeup of the nutrient line.
One example is a recent inquiry I placed with Jack’s, asking if there’s MgSO4 already in their Part A, can’t I just add epsom salts to the dry mix and dump both into water together? They said “maybe”, but they use anhydrous MgSO4, and Epsom is a heptahydrate (MgSO4.7H20), so it could impede the dissolution of the anhydrous stuff, creating a mess when the calcium is added (making gypsum).
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How can mixing order create a lockout? Lockout is attributable to pH. A solution is a solution imho, regardless of what goes in first the same reactions are going to happen. I’ve never done a mixing order and have never had pH problems.
the way it was explained to me is certain compounds can conflict with others when in a condensed form like adding undiluted PH up will lock I think mag and another mineral I cant think of when you drop it straight in. you can watch the cloud of chems form and drop when you add it straight to your mix. but yeah to keep lockout from happening is my understanding of the order of mixing. especially silica, that requires 15 mins before addind anything else.
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Well, pH is one cause of lockout, nutrient imbalance/toxicity is another, especially with synthetics. I never claimed to have all the answers, just the basics. You’d have to ask the manufacturers why they’re so adamant about mixing orders for their products. I’ve probably pestered them enough 
I suppose if the concentrates were mixed into water independently, then added together, it probably wouldn’t matter so much. I’ve spiked solutions this way before. It’s when adding concentrates to solution that certain bonds can form and cause lockout or fallout.
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Silica turns to jelly in the reservoir if mixed out of order.
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Well thank you all for getting me back on track. I had it locked in my befuddled brain that everyone was using suppliments (which is what I thought calmag was)for boosting the TDS between water changes. I thought that the left over nutes from water change would deteriorate after a few days and lose potency, lol. oh well live and learn eh? So thank you all for being patient with me, you truly are the best!
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