TheUnclesSam
Member
Yeah that makes sense, they will also take up breeding IN your airstone lol.. however if you do have beneficial bacteria it usually makes your res pretty foamy as they produce a natural bioslime to colonise.oh and also as some of you may already know airstones are a very inefficient means of aerating water you are much better off using the waterfall effect or fluming to aerate water. also air stones effectiveness can be severely hampered by the salts in nutrient solutions as they tend to build up in the tiny holes.
probably just repeating the basics here but sometimes a reminder can be a good thing.
When im brewing up bacteria I just use an open air tube for big bubbles as ive found this keeps the foam down a bit. Also they'll breed real fast so you res will probably need flushing more than the plants!
eg they need food in the res, they eat and breed at the same time making the water more viscous and making any bubbles linger into foam.
EDIT: at a guess I'd say the perlite is to "re-seed" a flushed res with new bacteria.