Sounds reasonable to me. If plant mass has tripled for example, the amount of nutrients that is required/or used, has also went up.
Personally I might try raising macros first because those are what plants use most of. Macros can affect new growth as well, regardless what the deficiency charts say.
Might just be low on Fe though. Shouldnt hurt anything to add a bit more and see.
Could also be a co2 issue, requirements for that has gone up too.
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