Thanks for all the information shared by the members of this forum. I've been reading and learning from you since 2013 when I joined, but with so many true experts, I've been a little shy of posting (just now passing 10 :icon_redf).
Now I would like to ask for your wisdom in answering questions about filtering for my 180 gallon low tech planted tank. Currently I'm operating with 2 Eheim 2217's and a Tunze 6045 powerhead on one end (tank is 6 x 2 x 2), and I'm probably going to add one to the other end.
My first question is how much GPH is really needed in a 180 gallon tank? I've read that you need 4x the number of gallons, and I've also read that canister filters are nitrate traps, so I'm a little confused. I've considered a sump, but my tank is tempered glass so drilling isn't an option and I'm a bit wary of sumps with HOB's. Looooooots of water if there's any problem...
Also, I'm planning on adding a UV sterilizer. After losing power for 3 days, I had a serious bout with disease unlike anything I've ever had. My poor fish had a tough time of it, and I have a generator now so that won't happen again, but I want to make a dent in existing bacteria and parasites beyond medications, thus the plan for the sterilizer, a Coralife 18w turbo twist.
Next question / questions: How feasible is it to add a UV sterilizer in line to one of the 2217's without sacrificing too much gph? Since adding the sterilizer will reduce flow, would it be better to get a separate pump or filter for it? I have a 2213 canister I could use, but if I use that, how would that work? Would it need to be set up as a regular filter?
Thank you so much for your time and expertise!
Adding more tank info:
180 g 6x2x2
2 Eheim 2217's
Tunze 6045 powerhead one end, most likely getting another one for the opposite end
2 air pumps with air stones
Moderately planted, mostly crypts, swords, hygrophila, nymphoides
Excel dosing daily, Flourish with iron twice a week
6 pearl danios
7 leopard danios, juveniles
7 albino corys
4 peppered corys
4 glass catfish (lost a couple in the power outage, will add a few more once I'm sure the diseases are gone)
9 cherry barbs
1 siamese algae eater
3 adult rainbows, 5 juveniles
2 golden rams
2 mystery snails, 2 nerite snails