Fish sure die with chlorine... only for carpet algea...

After you've washed and settled down the cement tank, just fill it with 4" of water and drop a few pallet feed and maybe some liquid fertilisers (you can get some from your friend with planted tanks... This will express the process...
Seeding it is super fast culturing... you'll have enough time to culture it... 1 week will see some results.

no worries. one tank is more then enough.

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Japanese Ranchu is another ball game