[houseofcards]

I am looking to increase the water flow in my aquarium in an attempt to eliminate bba. have an Eheim 2217, a HOT magnum filter and the Hagen elite mini (niko's DIY co2 reactor). How many powerheads should I have in a 55 gallon aquarium and what would be the ideal flow rate?

I've seen BBA grow in low-flow and very high-flow areas, so I don't know if it's ever been proven that not enough flow causes BBA. Personally I had a 72g setup for years with just a Eheim 2236 (less flow than a 2217) and didn't have any bba or other problems. What is your lighting schedule and co2 levels. If you can I would increase co2, reduce lighting duration and stay on top of your filter cleaning possibily adding Purigen or other organic remover to your filter media.

 

[houseofcards]

I have 4wpg with lighting at 7hrs a day. I haven't measured the co2 level but it's approx 1-2 bps. I don't have any test kits and I'd rather not go out buying all of them.

I don't know all the parameters of your tank, but are you running the 4 wpg all 7hrs. If yes, I would reduce if possible the other bank of lights to only 3/4 hrs, plus increase co2 if you can. I don't test anything either, but I run co2 as high as I can during day and turn off at night. I would say I'm running twice what you are on high-light tanks. Also doesn't hurt to stay on top of water changes and add purigen to filter.