[RiverOtter]

Hey guys,

I recently scored a 72 gallon oceanic bowfront off of craigslist. It's pre-drilled with a corner overflow.

Before the tank arrived, I bought a Fluval 405 canister filter with the intent to connect this to the tank.

Problem is, I really don't know the first thing about plumbing, if even if this is a safe thing to do.

I think I'd like to use the overflow, but use the canister instead of a sump. Is this possible/advisable?

 

[lauraleellbp]

It's do-able, but also a calculated risk. If you ever let the tank water level fall lower than the overflow intake, you'll end up with a burnt-out canister filter.

I started out with a plan to do this on my 90gal tank... but eventually scrapped the idea due to that risk to the canister, and actually found a great deal on a tank without an overflow.

Personally, I'd set up the canister in its own loop not using the overflow, and either remove the overflow or set up a 2nd loop to use it independent of the canister.

 

[RiverOtter]

It's do-able, but also a calculated risk. If you ever let the tank water level fall lower than the overflow intake, you'll end up with a burnt-out canister filter.

I started out with a plan to do this on my 90gal tank... but eventually scrapped the idea due to that risk to the canister, and actually found a great deal on a tank without an overflow.

Personally, I'd set up the canister in its own loop not using the overflow, and either remove the overflow or set up a 2nd loop to use it independent of the canister.

Oh, thanks. See, I hadn't thought of that. It's taking a while for my brain to wrap around this sort of thing.

I'm trying to think of other possible setups. I don't want to remove the overflow, as I don't think it's easy to remove the silicone, correct?

What if I did something like this? Somehow plug up the holes, then use the overflow in reverse. Place the intake somewhere in the tank, and have the output fill the overflow. Then I can conceivably place my heater and CO in the overflow as well, right?

Or is that stupid? Hah. Any other suggestions are very welcome. I can always take the Fluval back to the store.

 

[lauraleellbp]

You could do that, I think. Putting the heater in the overflow would probably work... but personally I'd get an in-line heater (Hydor ETH) anyways.

I don't think that would be the best way to distribute CO2 through the tank, I think you'd waste a lot through out-gassing that way. Especially in the waterfall coming out of the overflow.

I think you'd also have flow issues in the tank; you'd be wasting the potential output capacity of your filter to help keep the water circulating in the tank and prevent dead spots.

Many overflows aren't hard to remove.

 

[RiverOtter]

Thanks for all the help, Laura. I think the only thing standing in the way of me removing the overflow is the fear of removing the silicone. Or is it fairly easy to remove that stuff?

As for flow, I've got a couple powerheads that I was thinking of throwing in there, too. A couple Aquaclear 30's.

 

[lauraleellbp]

A razor blade should do it. :biggrin:

I had a tank I couldn't get the overflow out... but it was a DIY job, and the person had siliconed in the rear corner where I couldn't reach to cut it.

 

[RiverOtter]

A razor blade should do it. :biggrin:

Brilliant. I took an exacto to it, and it's coming off easily. I'll head out and pick up a paint scraper to take care of the rest.

Thanks again.

A final question then, if you don't mind - with the overflow removed, dould it be safe to use the pre-drilled holes with the canister? Or is that asking for a flood?

 

[lauraleellbp]

You could use the holes if you hook up bulkheads that fit the canister (and the holes aren't too small in comparison to the diameter of the canister tubing).

Though I think it would be best for purposes of flow to still use a flowbar up at the top of the tank for the return.

 

[Hoppy]

I think I would use the hole for the filter suction hose, connected to a short standpipe, reaching about half way up. The advantage of this is the filter is always primed, with no siphon to restore at any time. And, it is one less hose coming over the top of the tank.

You can also use it for the filter output. Just use the standpipe to connect to a spray bar or other outlet fitting - see the LokLine fittings, for example. I know that many people do this successfully.

 

[RiverOtter]

Thanks Hoppy, I think I'll do that. Out of curiosity, why would you recommend placing the intake only halfway up? Wouldn't it be safer (flooding wise) to be closer to the top? (See, I told you I'm a noob!)

Now, for an entirely different question - to protect my little chilli rasboras (B. Briggitae) from the intake, I'm thinking of clothing it in a fine mesh - like screen door screening, or similar. What do you guys think about that? Or can you recommend a more sightly/functional solution?

 

[Buckster]

I recently converted my 90 gallon reef into a freshwater planted and have hard plumbed my canister filter into the overflow bulkheads. To avoid the burning out of the filter due to accidental low water levels, I drilled 8 @ 1/8th inch holes near the bottom of the overflow allowing it to draw water only from the bottom if levels drop or top becomes clogged with plant matter.
The other benefits of this is by drawing water from low and surface, it skims the top and removes any surface scum. Also I don't have to shut off filter during water changes.

**edit**
Should also note, I removed the durso standpipe and let water flow directly out of tank from the bulkhead with a mesh screen covering it.

 

[RiverOtter]

Interesting, Buckster. I can imagine it must be a fine balance - because drilling holes in the overflow (to my mind, anyhow) would defeat the purpose of having it. Unless, of course, the 8 drilled holes are far slower than the waterfall - but then, of course, you've got to make sure that they're fast enough to keep up with the canister!

Too crazy for me, I think. I ended up just taking out the overflow, and I'm pretty stoked about the extra real estate I've got now. There are faint traces of silicone left behind, but the tradeoff was worth it. Now I've just got to figure out the plumbing, and I'm one step closer to filling this thing up!

 

[JennaH]

you can purchase a pre-filter for a few bucks, or make out out of a sponge

 

[RiverOtter]

Yeah, that's what I do on my 5 gallon, now, with an aquaclear (sponge). However, it does tend to slowdown suction quite a bit, and I don't want to burn out an expensive canister.

Or am I just being too paranoid?