Filter Intake/Outlet Positioning - 300 gallon tank

[danotaylor]

The rate of return determines the rate the water flows over the weir.
There’s quite a few folks that plump canisters to their sump intake/return holes.
The intake drain standpipe height will determine the water level behind the weir. Providing you have your water levels set appropriately, achieved by filling the main tank w all pumps off, let it overflow into sump to 2” from top of sump, then turn faucet off. This will prevent your sump overflowing as water drains during a power outage. Once set, turn pumps on and the sump will drain some as the main tank fills. Once water is recirculating, you can draw a fill line in your sump. This line is where you can safely fill to if you leave the pumps running

 

[Arrow1oo]

The rate of return determines the rate the water flows over the weir.
There’s quite a few folks that plump canisters to their sump intake/return holes.
The intake drain standpipe height will determine the water level behind the weir. Providing you have your water levels set appropriately, achieved by filling the main tank w all pumps off, let it overflow into sump to 2” from top of sump, then turn faucet off. This will prevent your sump overflowing as water drains during a power outage. Once set, turn pumps on and the sump will drain some as the main tank fills. Once water is recirculating, you can draw a fill line in your sump. This line is where you can safely fill to if you leave the pumps running

Awesome. I appreciate the help brother you saved me a huge headache of trying to hide my intakes.

I’ll probably move forward with one fx6 like you mentioned. If I for whatever reason decide I need another I can just follow the same process.

 

[Arrow1oo]

Hi danotaylor ,

Just a quick follow up. I’ve been working to set up this tank slowly but surely and I got my sump setup and placed the fx6 intake behind the weir as we spoke about.

One thing I didn’t consider is the fx6 has an auto-restart feature that kicks in every 12 hours to purge air.

It’s happened a couple times now, but do you think it’s possible that it’s messing with my drain/return alignment?

I have a herbie setup and I feel as though in the day I have it tuned but once the filter resets it goes back to need some small tuning.

Do I need to move the intake into the display to solve this? Should I just ditch the fx6 entirely?

 

[danotaylor]

I’m not familiar with herbie style drains to be honest. When you say you have a herbie set up, do mean air is regularly getting sucked into the FX6? If you drain intake is completely submerged and not sucking air into the filter I don’t think the purge feature would be an issue

 

[Arrow1oo]

I’m not familiar with herbie style drains to be honest. When you say you have a herbie set up, do mean air is regularly getting sucked into the FX6? If you drain intake is completely submerged and not sucking air into the filter I don’t think the purge feature would be an issue

So I tuned my herbie setup first, once they was balanced I added the fx6 intake behind the weir.

Naturally, I had to do some minor rebalancing again to make that work but I then tuned it to be fine.

However, every now and then, when the fx6 restarts I notice it won’t stabilize back to that level I had it at initially. It’s never a HUGE difference but what’s noticable is the noise of the water trickling over the weir.

Whenever the fx6 restarts, the water level behind the weir will hit the emergency, then when the fx6 kicks back on it will lower the water level a lot, then it will slowly rise back up.

My guesses are:

1. Some type of blockage in the main drain that I can check for

2. Evaporation is lowering behind the weir rather than in the sump (not sure why this would happen)

3. The fx6 is pulling inconsistent amounts of water causing my overflow level to always vary

If It keeps posing an issue, I’ll just remove the canister from the system. I could try to put the intake in the tank itself but I’m not sure if I want that type of visual clutter.

 

[danotaylor]

So when the FX6 stops to purge air, the rate of water flowing over the weir slows down because there’s not as much water entering the main tank from the FX6 & sump return. When the FX6 starts back up again, the Herbie drain and the FX6 drain, for a short period of time, are pulling more water from behind the weir then is flowing over it. It takes a few minutes for the outflow into the main tank from the FX6 to increase the flow of water over the weir once more. This is what’s causing the fluctuations in water height behind the weir.
Another option is to put the intake drain in the sump and the outflow remain in the main tank. When the FX6 purges and restarts the water level behind the weir won’t change, the water level in the sump will. That way the FX6 is still providing mechanical & biological filtration, and generating some flow in the main tank. In this scenario the piping remains hidden from sight.

 

[Arrow1oo]

So when the FX6 stops to purge air, the rate of water flowing over the weir slows down because there’s not as much water entering the main tank from the FX6 & sump return. When the FX6 starts back up again, the Herbie drain and the FX6 drain, for a short period of time, are pulling more water from behind the weir then is flowing over it. It takes a few minutes for the outflow into the main tank from the FX6 to increase the flow of water over the weir once more. This is what’s causing the fluctuations in water height behind the weir.
Another option is to put the intake drain in the sump and the outflow remain in the main tank. When the FX6 purges and restarts the water level behind the weir won’t change, the water level in the sump will. That way the FX6 is still providing mechanical & biological filtration, and generating some flow in the main tank. In this scenario the piping remains hidden from sight.

First off, really appreciate your help on this months-long journey to trouble shoot this lol.

I appreciate the run-down, this whole sump experience is exposing my weak fluid dynamics knowledge.

So I did some digging and can confirm the line wasn’t clogged. However, I did notice that my main standpipe was only about 5 - 5.5” below my emergency, rather than the 6 - 7” I’ve seen recommended so I might shorten that pipe by an inch or so to help it achieve full siphon easier and suck in less air.

I had no idea putting my intake in the sump was an option. If that’s the case I will definitely resort to that assuming I can’t get it to work behind the weir.

Thank you again!

 

[danotaylor]

No worries mate