If you use the overflow box the interior of the box essentially becomes a sump. As you evaporate water, the water level in the aquarium remains the same, but the water level inside the box drops. Drop it too low and the canister sucks air and loses prime.

The Fluval FX6 is the best suited canister for hookup to a drilled tank directly as the screw down clamps can provide an adjustable and tight seal. Most other canisters without an adjustable seal will work fine with an over the rim siphon, but if you put them through a bottom drain and turn the power off they leak like crazy through the gasket seal on the lid.

For any canister other than the FX6 I would plug the bulkhead holes and use the included over the rim intake for the canister. The outlet can be any way you like it (plumbed through the overflow or over the rim).

As long as you are mindful of the water level inside the overflow box you should not have any issues.
Andy

 

So what your saying is, cap off the bottom of the weir, don't use the drilled tank connections. Then the weir becomes a sump. Put the intake of the canister into the weir, and as water evaporates , it will drop in the weir, and not the tank. I could use a ATO ( Auto top off ) to control evaporation in the weir, so I'm not worried about that dropping water, as the ATO will keep it constant

What about a Fuval FX5 ? A FX6 seems so large for a 90G tank no ?

Does the FX5 and FX6 has the same connection for hooking upto the drains so they don't leak at the lids?

I'm guessing when you cut power, the siphon back down to the canister is to much, causing the canister to have no where to put the excess water, making the seals leak

Also if you bypass the weir, how do you keep the water from becoming stagnate and still in their then? It would be filled with water with no movement

 

The FX6 is the same exact canister as the older discontinued FX5. Same dimensions and specifications. However, they do claim that the new FX6 is a little bit more efficient. And no....an FX6 would not be too much for your 90 gallon. I have an FX6, a Fluval 406 and a Koralia 1500 gph powerhead in my 6' long 125 gallon tank.

 

Ok thanks, I'll order the FX6 tonight then
My wife is going nuts over how loud the sump is
Should I use the bulk heads with the FX6 ?

How often does a canister get serviced media ?

 

Can't answer your question in reference to the bulk heads. But maintenance should be every couple of months if running two canisters alternating between the two. Also depends on how heavily stocked your tank is, but the FX6 can hold a large amount of media in all of the trays if you want.

 

I have a ton of media all ready starting to get established in my sump, I can put in it. So I need 2 FX6 canisters? My stock is going to be around 23 Mbuna

I just ordered it from Amazon Fuval FX6

My wife hates this sump. Now I just have to figure out how to plumb it, with or without the bulk heads

 

No you don't need two FX6's....that would be a little overkill. One FX6 should be fine, but secondary filtration is a good idea in case of a failure and easier maintenance. If you want to add a second filter you could go with a much smaller and cheaper ones maybe even a 206 or 306.

 

Thanks, What media do you recommend for a canister?

Right now I have Seachem Metrix in the sump, I also have Bio Sphere;s , but I'm not sure if they are made for canister filters

I also have polishing pads, maybe I can cut them to fit?

So on a canister filter, I don't clean the bio, just the mechanical right? And I'm guessing the mechanical is probably a sponge?

How often does that get cleaned?

 

I found this, FX5 plumbed into the bulk heads. Looks Like I'll do the same with the FX6 and keep the stand pipe low in the weir so it doesn't suck any air into the canister filter

I cancelled the order from Amazon at $329.00 and ordered it from Big Als with 10% off, total cost $270 free shipping!

 

As far as media...I just used the bio media and mechanical media (foam filter pads) that came with the unit. Just remove any carbon media that may come with it. If you want to add more media, the Fluval Biomax ceramic media would be fine to add more bio media.

In reference to maintenance, I was told to leave it alone for 12 to 16 weeks before cleaning. Then once a month after the tank is established or once every other month if you have two canisters alternating between the two. And yes, the bio media will be fragile until well established. Polishing pads are great for fine particles in the water but will require more cleaning as they tend to clog easily.

Great price on the FX6...it's a great filter!

 

Ok, I saw a few post on hooking up a canister filter to the bulk heads. One was simple, he just used barbed bulk heads which I have, and clamped the hose onto that, simple

Only Issue I'm not sure of, is I have to make sure the tank doesn't evaporate below the weir intake on top, otherwise the weir will just run dry in a few seconds with no water overflowing into it.

So back to the canister cleaning

I'm worried of Nitrate build up in the sponges in the canister. I understand the bio part, and will leave that section along for a few months, but shouldn't I at least rinse the sponge part out and pads inside the canister?

 

I was told to leave it alone for 12 - 16 weeks. I've had my tank up and running for 8 weeks now and do weekly water changes with nitrates at 10 - 20 ppm. As long as you can keep nitrate levels below 40 ppm you should be fine. I was also told to watch for a reduction in flow as an indicator that it may be time.

 

Ok thanks, i.appreciate it, thanks for the help

 

You could purchase a HOB filter for emergencies like a power failure. The bacteria would have access to oxygen so they wouldn't die off.

 

Thanks. So far I'm good with everything, and ordered the canister

Only thing I'm still not sure, I guess I have to make up my mind in the next few days is:

Close holes, and use it like a standard filter up over the back

Or use the bulk heads, put the intake and heater in the overflow box, and just do the return over the back, or I could use the return with the weir also

I don't like putting the return with the overflow box, because how is the fish poop supposed to go into the overflow box, when the return line is pushing water out of it

Still pondering on what I'm going to do with the overflow box

For plumbing, I found a few threads, people just use black 3/4" hose to the barbed bulked heads and clamp them on, simple