Because fish/kg is very expensive here, we do not have ocean coast and we have endless freshwater supply. There's not much need for water cooling systems which are more complicated than heating. This is small time thing in Finland too, more at the trial stage I doubt it will become big business.
Typically indoor fisheries establishments are for raising from eggs to juveniles that can be released into the wild.
The CA method of raising fishes/prawns tells nothing. WHat you need to manage in almost closed system is nitrogen. Aerobic fitration for oxidation of NH4 to NO2 and NO3 and NO3 reduction to N gas. I have seen zero dicussion, nothing, nada about this.
People buy into this "method" that there's no info about, no explanation, no publications for sure, no pictures, no equipment shown anywhere, absolutely nothing.
That's an obvious sign that nothing has been invented.
Anyway these things have their limitations, water change is always going to be needed regularly.
If you go to some big sea-world with huge sharks that make huge size turds it can't be managed with any system, it needs manual cleaning and water change, these places are connected to ocean and water taken "free" from the ocean. Salt water is definitely no-no for indoor farming because costs are very high due to need add salt(s) and the ocean fishes are the most valued ones, it's too expensive to raise tilapias indoors no matter how good system you have.
"Mark "It's extremely expensive to farm fish in a tap water system or any closed system for that matter." Why is it then thar such a system is on the stocks in Finland?"
