Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Works somewhat, but not good when combining wands

I bought 4 of these to span my 8' tank. My plan was to have a solid bubble wall against the back of my tank. I have a very powerful air pump (meant to supply many tanks for all sorts of things) and no matter what, the bubble wall was incondistent. Some section of the wand worked great, some sections had no bubbles, but the sections after them did, which means the air was getting through.So I wasted allot of money to just used 14" of these in both corners of the tank. The bubbles are bigger than I wanted too.Overall this is a pretty poor product.