Weir operation and surface skimming?

[jgvergo]

I have a complete DIY Bean Animal setup (my first reef). Everything is working well except I am getting some film on the surface of the DT. I think it's because the water is so high that most of the holes in my weir are below the surface and "sub-surface" water can flow into my overflow. The holes in my weir are ovals, about 2 inches tall, and most of the oval is below the surface. Do I need to drop the level of the water in my DT?

 

[AlexStinson]

Without pictures, I would guess your overflow is too high, or your weir is too high, or your waterflow is higher than your weir is rated for. Water should not 'flow through' but 'spill over' if that makes any sense.

 

[jgvergo]

Alex, I think the weir can handle the flow without any problem. If you can make it out from the picture, a good 2/3 of the wier is under water. I could drop the level of my overflows (full siphon and open channel), but this is the tricky part...I don't want to drop the level of the water in the DT. It is already relatively shallow (17") and to give up another 1-2 inches for the overflow is not an attractive option for me. I'm thinking of possibly blocking off the bottom half of the weir. Good idea or bad?

 

[Jimbo662]

In order for it to work properly and skim off the top the water level in the overflow has to be slightly lower than the level in the tank itself. You can block the lower portion of the wier. I basically did that on my Fluval M90 and it's working fine.

 

[twilliard]

What is your return rate?

 

[TheEngineer]

That height looks fine to me, at least from the angle of the photo. Just get more surface agitation and you should be fine.

 

[jgvergo]

In order for it to work properly and skim off the top the water level in the overflow has to be slightly lower than the level in the tank itself. You can block the lower portion of the wier. I basically did that on my Fluval M90 and it's working fine.

Jimbo, can I ask how you blocked the lower portion of the weir?

 

[jgvergo]

What is your return rate?

Twilliard, I'm not sure what my return rate is because I have a gate valve on the return line. I use 1 inch PVC and ~10 feet of head height. According to some flow rate calculators, my full siphon should be running at ~1200 gph. I have 2 90 degee elbows and 1 45 degree elbow, so it may be closer to 1000 gph.

 

[jgvergo]

That height looks fine to me, at least from the angle of the photo. Just get more surface agitation and you should be fine.

icecool2, I have played with more surface agitation, but it tends to cause a lot of bubble in the DT. I'm trying to achieve a crystal clear look, so my goal is to not have any bubbles if possible. Of course, if it comes down to a decision of bubbles vs. the health of the tank inhabitants, I'll live with bubbles.

 

[Jimbo662]

I was able to find an after market wier that fit my tank.

http://shop.mediabaskets.com/inTank-Universal-Surface-Skimmer-M90SS.htm

 

[TheEngineer]

icecool2, I have played with more surface agitation, but it tends to cause a lot of bubble in the DT. I'm trying to achieve a crystal clear look, so my goal is to not have any bubbles if possible. Of course, if it comes down to a decision of bubbles vs. the health of the tank inhabitants, I'll live with bubbles.

Surface agitation won't give you bubbles, at least it shouldn't. You just want the surface of the water to have some "action" to it. You shouldn't be able to look down to the bottom clearly. It should be obstructed by the surface movement.

 

[twilliard]

Yes wave actions (slight) will help move the surface tension through the overflow.
Every now and then grab a (unused) toothbrush and run it up and down the slots to help break up any oils.

 

[jhoop]

I had that problem. The overflow box was not high enough and tank had a low water level. I used " Black Tape " to cover the weir holes. Been there for a year. The same tape. Just apply clean and dry.

 

[reef_junkie]

Since you have a bean animal setup you should easily be able to adjust you dt water level. My bet would be thats the fix.

 

[jgvergo]

I had that problem. The overflow box was not high enough and tank had a low water level. I used " Black Tape " to cover the weir holes. Been there for a year. The same tape. Just apply clean and dry.

jhoop, Do you mean electrical tape?

 

[jhoop]

Yep 3M black electrical tape. Stretched across the bottom of weir. It brought up the water level in the tank.

 

[ReeferBob]

Your intuition is correct, block all of the lower holes they are useless on a marine tank. Force all the water to the top overflow holes.

 

[louienardi]

Your intuition is correct, block all of the lower holes they are useless on a marine tank. Force all the water to the top overflow holes.

How does one block the weirs at the middle of an overflow built by Marineland....

 

[ReeferBob]

I would silicone over them with similar colored plastic. Never tried the electrical tape trick - sounds like a good idea too.

 

[louienardi]

I would silicone over them with similar colored plastic. Never tried the electrical tape trick - sounds like a good idea too.

Wish I thought of that before stocking the tank... I have to check their site. The may be closed as I can lift the top of the overflow and I now pushed it all the way down.