Backyard Aquaponics
A place to discuss aquaponics

What is differance between blue and whit barrels used in system. Also what about plastic barrles used for heat storage in greenhouse. Do I have to remove them in hot wather.

The white barrels might not be as long lived out in the sun and can grow more algae as the light penetrates more. So long as the barrels held only food grade stuff or stuff that can be completely cleaned out to make them food safe then they are all good.

As for water containers to help store heat. Essentially they are meant as thermal mass and if painted black will tend to absorb more heat to help out in winter. In summer, they will still be thermal mass but you might want to cover them with something reflective so they don't absorb as much heat during the day. Also, in a greenhouse, during summer in a hot climate, it is good to be able to open up the green house as much as possible. I take the plastic off the sides and ends of mine in the summer so it is more of just a roof then.