Just trying to pick some brains here. Currently putting a new soil mix together and I was wondering if anyone has preferred one over the other. I realize they both add their own benefits aside from PH adjustment, but I wanted to know if using OSF would work just as well as dolomite for a liming agent. Thanks in advance! 
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Dolomitic lime is 2:1 calcium to magnesium, that is usually too much magnesium.
Oyster shell flower is 96% calcium and micronutrients and can be used without the worries/problems that too much magnesium can cause(calcium lock out/soil compaction)
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Thanks @Garden-Buddy for the input. Does OSF adjust the ph enough to not require lime?
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lime will act faster. oyster shell gonna need some time to be digest my microbes.
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Thanks for the reply @anhthormap ! I think I may do a test for everyone… I thought just adding it to a base mix would bring up ph. Thanks.
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100% Natural
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For cannabis a 2:1 calcium to magnesium ratio is actually perfect! So no issues there
I’d personally use oyster shells as contain a complex of micro nutrients…
Just my .02
Alaskagrown
EDIT: TBH I’d actually use both as will give an extended calcium release as both break down at different timings…don’t forget about egg shells as well!
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@Alaskagrown I think I will make up a couple batches and send off for testing to see if there are any differences. I’ve always used dolomite personally with no issues but wanted to get a better reading from you folks! Thanks for you’re professional opinion bud!
@HashstasH Thanks, I’ve read that along with quite a few other articles, just trying to get some answers I suppose. Great read btw!
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Dolomite is slow release so that establishes the minimum base level of Ca & Mg. I add a powdered eggshell, this is a short and medium source of Ca. It’s a free byproduct and crushed oyster shell is at a premium here.
Another good one to consider is Gypsum. S is always good to add a little.
Cheers
G
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Looking back at my old notes… I found that doing a 1:1 ratio of Dolomite to Gypsum seemed to be perfect for the Ca: Mg ratio and provided good amounts of sulfur along with buffering the soil at an optimal pH level. When doing a pseudo coots mix with SPM/EWC/FFOF/Perlite I add 1.5 cups of both per bag of FFOF and everything comes out great.
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I used dolomite and some gypsum when making soils. The cost difference made up my mind.
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What, you don’t get a great deal on oyster shells where you are??? 
@MidwestMover [lol, username checks out]
I agree, I’m in a hotbed of oyster activity (oh boy, starting early with the puns), but around here they recycle them and use them to re-seed new beds and create a foundation for the babies to anchor onto, so it’s actually just as much an ‘import’ as if I were a few hundred miles inland.
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There’s a seafood restaurant near here where the parking lot gravel is oyster shells that they throw out there 
… hmm
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Had to translate what they call it here. Concha de ostra. I still have some in my bucket of soil amendments. I may put some in my coco.