29 gal is too small for five bristlenose and still maintain good water quality IMHO
I keep long finned albino bristlenose X3, and Royal Pleco in 55 gal With Rena XP3 filter and Aquaclear 70 powerhead with quick filter attachment.XP3 Filter + quick filter attachment need cleaning every couple week's due to waste created by the four plecos.
I change 50% or 60 % of the water each week normally.
Twice weekly water changes with cooler(not cold) water would be my suggestion, along with good quality pellet food such as New Life spectrum for large fish(once daily),occasional (once a week), food such as Hikari Sinking wafer or Carnivore pellet for a bit of animal protein,and once a week Zuchinni sliced long way's and left in tank over night.(Babies glom onto this too).
My experience tell's me that clean cool water, NitrAtes around 20 ppm, is difficult with the number's of this species you are keeping in relatively small volume of water.
Had a batch of about 15 babies exit the cave in my 55 gal two week's ago,and male currently tending egg's once again .
I keep them in moderately hard water 12dgh,pH 7.8 from the tap,temp 76 degree's F with afore mentioned food's and maint routine.
I currently have them over straight Black diamond substrate about four inches deep ,and their digging in this material has resulted in replacement of two impeller's in the RENA XP3 due to sand damage despite pre filter over the intake to protect a few hundred Cherry shrimp that also inhabit the 55 gal.
Try twice weekly 50 % water changes with cooler water for a few week's and do consider larger tank IMHO.