Dear fish growers.
I have a question.

I live in Latvia which is hot in summers (+30 ℃) and cold in winters (-20 ℃).
I want to raise rainbow trout in my backyard in a very small pond. Trout does not love any heat and therefore the pond will be in the ground and will not be exposed to direct sunlight. It will be aerated and the water flow will be ensured throughout the year as is required for trout. At the same time the pond will be isolated with membrane from the soil.

The problem I have is this:
How do I get rid of the ammonia in the water during summer and during winter?

For summer I have an idea to have a hydroponics setup therefore making the whole system as aquaponics which will clean the water for fish from toxic ammonia by converting it into nitrate, a plant fertilizer. But maybe there is a better way for that in summer?

And I have absolutely no idea how to remove ammonia during the cold winter.


Thanks for your help!