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Dry dosing vs. solution

Kezzab

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Hi - ive bought the APF EI starter kit.

I was wondering about dry dosing the salts into the sump, rather than mixing up a solution. This is new territory for me.

What are the downsides/risks of dry dosing like this?

In particular, is there a risk that if i add each salt separately to the appropriate level for each, that i am actually adding too much of something when they are in combination?

Thanks
 

Zeus.

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IMO dry dosing 'if the tank/dry dose is big enough has many advantages, you could even mix the salts for Macros and Micro batches. No mould or interactions pipework/bottles to clean

Solution is just convenient if you have an auto doser esp for Holidays
 

Kezzab

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OK thanks @Zeus. Bear with me here, i'm being a bit dense and want to be sure i'm getting this right.

The APF EI mix is 4tsp KNO3, 1tsp KH2PO4, 6tsp MgSO4 mixed in 500ml water. Dosage is 10ml per 50l, 3 times a week. Tank is roughly 220l. So for arguments sake 150ml per week. So a 500ml bottle of mixed solution will last just over 3 weeks.
Trace mix is 1tsp in 500ml, same dosing as macro.

So i'd be using 12 tsp of salts in 3 weeks.

But instead of mixing in a solution, i just thoroughly mix all the dry salts in a tub in this ratio.

On this basis i'd dose a total of 4 tsp of this combined dry mix a week (split across three doses in a week) to give me more or less the same as the recommended dose for it in solution.

Am i getting that right?

Thanks!

K
 

Zeus.

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1615390026987.png

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If you mix then divide there will be fluctuations in the ppms dosed, as the salt size and density varies. But it should to to far off.

IMO it would be better to split each it a week worth then part dose over the week, weekly single dry dosing below, but weighing tenths and hundredths of a gram soon gets tricky

1615390471959.png
 

sparkyweasel

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Thanks, that's really useful. I suppose if i give the tub a good shake before taking a spoonful i can reduce the variability somewhat.
K
If the crystals of the differrent salts are different sizes, shaking will separate them rather than mix them. Like shaking a bowl of mixed nuts to bring the Brazil Nuts to the top.
 

Zeus.

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Like shaking a bowl of mixed nuts to bring the Brazil Nuts to the top.

Yes, thats maybe one of the reasons I am going off Trace Salt mixes, as I don't believe the typical analysis will hold true for every 5g or teaspoon full. The beauty of a commercial AIO is they make them in large batch's at a time, thousands of litres. When you buy single salt grain size is irrelevant if you weigh it, keep the mass above 5grams and serial dilutions if needed and you cant go far wrong. It can just work out quite expensive to get the trace salts to start off with plus you need to be very methodical when making the trace solution mix, easy to make mistakes when wife/kids are in - need a 'do not disturb sign'
 
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I dry dosed my sump in the beginning, but I got tired of pulling out the tiny spoons each time. I made solutions and I pump them in now 3 times a week. Sounds lazy I know, but dosing isn’t something to be lazy about in a high energy tank. Do whatever works for you and your more likely to keep up with.
 

Kezzab

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If the crystals of the differrent salts are different sizes, shaking will separate them rather than mix them. Like shaking a bowl of mixed nuts to bring the Brazil Nuts to the top.
In my experience with Brazil nuts you need a rather deliberate shake to get them to.the top, a vigorous random shake Is a bit different. I've mixed one small batch as an experiment and it looks well mixed.
We'll see how we go.
 

zozo

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I also dose directly into the sump with spoons of dry salts... But each salt separately and yet not tired of that.

I have no experience with mixing dry salts for fertilization purposes... All tho, as an amateur BBQ chef I really like to mix my own meat rubs and enough of it that it lasts me more than one cooking session. a great rub I can recommend to anybody font of BBQ:
  1. 60ml Salt
  2. 60ml Brown Sugar
  3. 60ml Smoked Paprika
  4. 15ml Garlic Powder
  5. 15ml Onion powder
  6. 15ml Black pepper (coarse)
  7. 15ml turmeric
  8. 15ml cinnamon
:p
The catch of my story is while the canister gets more empty the mix slowly gets noticeably less sweet. Doing the math, the sugar disappears first, obviously. So also does the coarse black pepper. And looking close it actually is visually noticeable as well because there are obvious color and grain size differences. But it stays a nice and good multi-taste BBQ rub...

Looking at the aquarium dry salts separately in a glass pot next to each other, Epsom - Kno3, Kh2po4, and K2so4. I definitively see 4 distinct different grain sizes, most likely each with a different specific weight.

IMG_20210311_122756143.jpg

Some gut feeling (about simple physics) tells me, with mixing this similarly as my BBQ rubs, the very same shifting will take place and the composition will change after each use. :)
 

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