I was wondering if i could use a air pump in a betta tank, i don't know if it would ruin the bubble nest, and is it safe for the betta?
It is a very good idea (in fact all fish need a filter) to add a filter to a betta tank, but it is important is not too strong as they are not the strongest swimmers and will tire easily. Also the flow rate can disrupt the bubble best (as you pointed out) and you can add some floating plants for him to build his nest amongst, this acts like a scaffolding for the nest to resist flow/current.
How big is you aquarium and what type of filter/air pump are you thinking of including?
If you have a small aquarium, under-gravel filters take up the least room!!
I have a filter in it that is fine, but i wanted to have a small air pump so i could put a "bubble wand" or something like that to have bubbles cover the back wall. I have a filter called a whisper 2-5 gallon filter and i have a 5 gallon tank.
add a air controller or check valve on the air tubing to control the bubbles.It wont interfere with the bubble nest if kept at some distance.keep it near the rear corner of tank