I have a 36 gallon tank with an Aqueon® QuietFlow Aquarium Power Filter 55/75. as of now there are 2 red minor tetras and 4 neon tetras. I had another red minor tetra and 4 more neon tetras that all died over the last week. (There were a couple more that died the week before). 

I used to have the 30 gal version of the filter, but it didnt seem to be able to keep up and the algae got out of control. I did a 50% water change, upgraded the filter to the 55/75 version and soaked all the decorations in bleach (and rinsed them off well after). It cleared up the water very well and the new filter seems to be working well. 

About a week after I did the cleaning I got the new fish and since then they seem die off about 1 per day. Within a day of putting them in the tank, I notice that a couple of the neon tetras seem to have bits of their tails missing. Then about once a day I see a dead fish (almost always a neon tetra) thats sucked up against the Is this a case of an overagressive red minor tetra and they only get stuck by the filter after they die, or could my filter be too powerful and they get sucked up into it and not being able to swim away?

Edit: One thing I forgot to mention is that I got a water test done at PetSmart and they mentioned that the only issue is the Ph seems a bit low and I should do a 25% water change, could that be the issue?