tandem filter set up

[dsotmoon]

Hello, i currently have a rena xp4 on my 135G freshwater tank, the filter itself works great, very quiet, easy to clean, plenty of room for media

however, the flow rate even when clean doesnt seem to be the advertised 450 gallons per hour and i'm wondering if it is cleaning the water enough, when i first started researching this size tank most suggested 2 canister filters

what i am wonder is if i did add another filter i dont want 2 tubes out and 2 tubes in, can you or has anyone run filters in tandem? (see my crude illustration below ) what do i need to consider if i did it this way? the same size canisters? a lower GPH filter as the first one? a "pre-filter" of sorts?

any advice or suggestions appreciated

[Ruadh]

Originally Posted by dsotmoon

Hello, i currently have a rena xp4 on my 135G freshwater tank, the filter itself works great, very quiet, easy to clean, plenty of room for media

however, the flow rate even when clean doesnt seem to be the advertised 450 gallons per hour and i'm wondering if it is cleaning the water enough, when i first started researching this size tank most suggested 2 canister filters

what i am wonder is if i did add another filter i dont want 2 tubes out and 2 tubes in, can you or has anyone run filters in tandem? (see my crude illustration below ) what do i need to consider if i did it this way? the same size canisters? a lower GPH filter as the first one? a "pre-filter" of sorts?

any advice or suggestions appreciated

I'm not exactly sure what you're trying to accomplish by running two filters in series.
Plumbing it the way you show won't give you more flow, only more filter capacity, the same effect as having a filter twice the size as one of those single ones.
If you want more flow with two filters you have to run them as separate units, or at least in parallel with larger hoses to and from the tank to the first filter.

I use two XP4's on my 175 gl. with the inlet line at one end of the tank and the outlet for that can on the opposite end. Same with the second can, the inlet for it is about a foot from the outlet of the first filter.
That way each filter draws it's dirty water from the opposite end of the tank. Each outlet is close to the top and the inlets extend down close to the bottom.

[jim692]

Originally Posted by dsotmoon

Hello, i currently have a rena xp4 on my 135G freshwater tank, the filter itself works great, very quiet, easy to clean, plenty of room for media

however, the flow rate even when clean doesnt seem to be the advertised 450 gallons per hour

It won't give you 450 gph. The pump could technically move that much water but you have the friction and head loss from the canister, tubing, media, and elevation of the tank. So they claim only 190 gph after all that.

Aquarium Pharmaceuticals Rena Filstar XP Canister Filter XP4 Filter 450gph - Animal World Network
Aquarium Pharmaceuticals Rena Filstar XP Canister Filter XP4 Filter
• Flow Rate - 450 gph • Suitable for Aquariums - 265 gal • Canister Volume - 3 gal • Water flow (with media and tubing) - 190 gph

You could improve the flow rate some by:
Lose the tubing and replace with rigid PVC pipe (1" PVC would have much less friction loss than that tubing.)
Reduce the amount of media inside the canister. (not always a good idea)
Keep the filter level with the top of the tank.( not great looking, but makes the pumps job easier due to less head loss.(elevation difference))

Personally I would go with the PVC first and elevation second. Would probably add 35% to 45% to it's performance. (educated guess)

You could run 2 off 1 inlet and 1 outlet pipe (1 1/4" PVC) and split them off at the base by the pumps but better to have them in parallel than in series like your diagram. You should also have isolation valves for each pump for servicing, etc.