Will my accident Florapride overdose hurt my fish ?

[LurkingGrue]

Sooooo... I guess I thought when I upturned the large bottle of FloraPride that there was a little nozzle on the bottle to let you squeeze a bit at a time into the tank, but in fact I just dumped most of the bottle right into the water following a fresh water change .
My tank is a 55 gallon, many plants, and has gouramis, tetras, loaches, a cat, knight/fan dancer gobies, and numerous ghost shrimp .
I know the loaches and scaleless cats can be especially sensitive to certain medications and 'supplements', as can inverts .. should I rush to perform another water change and get the overdose out of the system ? Will it impact the biological filter at all ?
FloraPride is Tetra's brand of all-purpose plant helper, its a '0-0-3' fertilizer and the 'guaranteed analysis' on the back says it has at least 3% soluble potash (K20) and .19% iron . The whole bottle treats 250 gallons, I probably added 150+ gallons worth of that, so a triple dose .
How concerned should I be ? Any prompt answers are especially welcome !

[Gemini]

Well I'ver never overdosed ferts but I would be doing at least a 50% water change. Someone else may tell you it's fine but I would be worried about scaless fish and shrimp.

[Scrup]

Personally, I wouldn't sweat it. Don't do it again, but other than a water change nothing can really be done.

Might get an algea bloom though.


*edit- I should restate that, I would do a water change, and after that you should be fine, nothing to worry about. if you dose 3x the normal amount, I would do a 2/3 water change.

[LurkingGrue]

Thanks for the prompt responses, guys :)
To update, I did a freshwater iron test and it looks like there's approximately 0.2ppm of iron in the tank after the overdose . The instructions for the iron test (caring about iron content is new to me) recommend dosing the tank with additional iron if the test shows less than 0.5ppm, so does this alleviate any concern about injuring the livestock with my current iron level?
I'm assuming the iron is primarily the concern here, and not the potash, is that a mistake ?