Here’s a grammatically corrected version of your text:
“This softener works amazingly well. The connection was easy, and it looks reliable. After a couple of months, there haven’t been any problems. I am very satisfied with this product.”
Here’s the corrected version of your text:
“For small water system rooms in residential houses, I would suggest a more space-saving shape, such as rectangular or square. The height could be taller to maximize space efficiency.”