Metro doesn't work fully. It has only an 86% success rate of irradiating protists. There are other groups of medicine that have a better success rate, still bleach at present is the best option.
I'd also like to put calm to some fears that Dino's are in every tank.
No they are not. Again this is more aquarium ancedotal theory rather than a science.
My first aquarium setup suffered them. This was built on pure live rock and live sand, of a very good quality.
I'd added no end of copepods, amipods mini stars etc to boost biodiversity.
It did become infested in Dino's.
The second setup was a mixture.of live seeded synthetic and premium Fiji. Same story.
This time it's live synthetic and dry rock, mb7 cycled, with added amipods and copepods. No trace (thank God) of Dino's.
Dino's are no different than anything else you introduce. Be it bryopsis or bristle worms. If they are on the rock or frag, if you don't quarantine or dip well enough. You will contaminate.
Fresh water does kill Dino's based osmotic shock. It will rupture the cell wall. I've read success stories brining sg down to 1.010.
I've stated before my belief (quote my belief) the reasons some blackouts work. I believe it is to do with the users filtration and diversity of critters feeding in dark.
Lights out sends the Dino's in to the water column to seed new areas. Powerful filtration and carnivorous bio diversity over an extended period could very well be the key.
Purging sand from aquarium will prevent a refuge for the cysts.
H202 dosing works on some strains of Dino's but in dosgae a.ounts is insufficient to kill osteo Dino's. If you want to h202 those you need a few hundred ml per litre. But that's fatal to just about everything. How do I know? I tried it.
PS I'm not having a dig here at anyone but there is so much disparity in this hobby, it's almost impossible to find any truth.
So far. Bleach each works.
+1