As far as aeration... Your Intex should have come with a little fountain/sprayer thing that hooks onto the pump outlet on the inside. Take off the fitting on the inside wall and replace with the fitting and hose that connect to the sprayer. You can direct the sprayer to spray droplets all over the top of you water and, thus, aerate your pool. For me, I'm using a Pool
Devil on the outlet... its a really cheap skimmer with a sock that works on the "venturi" principle... it goes on tout outlet and as the water is streaming in from the pump, it sucks the surface junk into the sock. The skimmer that tries to hook onto the side of the Intex has never worked right for me and always gets shifted when people are swimming. Anyway, the Pool Devil is adjustable and I can set it to create a little aeration action while it is skimming.. and there's no way I'm spending more than $20 for any accessories for a $200 (on sale last year) 18 x 48 Intex. Use the tools you have and the knowledge from this site. I've been doing the BBB thing since the day I put the pool up last year and all has been fine. Stay away from the pool store and be patient. Also, and I could be very wrong here, but I don't worry too much about PH and Alk. We're in a really high ALK area here... couldn't grow an azelea if my life depended on it... my ph stays pretty high as well as the alk, but in the Intex, it's not hurting anything. Pool is clear and chlorine is stable. I've been reading and lurking here for over a year... I'm sure Carl D will correct me if I'm wrong about the PH. I quit worrying about it though and just worry about keeping the pool clean and keeping my chlorine levels. Hope this helps.

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LaLa in TX
18 x 48 Intex (affectionally known in these parts as our "white trash pool"
And very thankful that the people in this forum don't laugh at us!