Please help, planning to cut larger overflow teeth

[Sh55]

I recently upgraded my main pump (sump to display) from a submersible 250 gph pump to an external 630 gph pump. The problem I am now facing is that the water level is dangerously high in my display tank because my overflow teeth seem to be too thin for this much turnover.

 

The overflow teeth in my sump handled the increased flow with no change to the water level, but the display tank overflow teeth are much thinner and therefore need to be modified.

 

I have a split loc-line return line, and to temporarily fix the problem I ran one of the returns back into the overflow box to cut the turnover by 50% (close to the original 250 gph rate).

 

My question is this: Does anyone have advice on how to increase the width of the teeth in an acrylic overflow that is attached to a tank?

 

I have looked up a bunch of videos on how to cut acrylic, all of them have me worried. I wanted to see if anyone else here has had to tackle this problem. There is no easy way to remove the acrylic overflow part itself, it is thoroughly siliconed to the glass overflow box, so I will have to perform the modifications while the part is on the tank. The tank and overflow is a custom build by glasscages.com, I attached one of their stock photos that closely resembles the overflow on my tank.

 

The best (scary) plan I can think of is this:

 

1) Add a filter sock to the drain in my sump

2) Carefully drill out each tooth to a wider diameter with a cordless drill

3) Keep my return pump on so that tank water is running over the teeth as I'm drilling (to cool them)

4) Catch the drilled out acrylic from the filter sock on the drain (least of my worries)

[StevieT]

I've never cooled acrylic when drilling or cutting it's not needed if you have the right sharp bit.

 

Dremel, router, drill will all work

[Sh55]

Thanks Stevie, I'll make sure I get the right hardware. I assume I should still go slow to ensure the material doesn't melt?

[GTi]

I recently upgraded my main pump (sump to display) from a submersible 250 gph pump to an external 630 gph pump. The problem I am now facing is that the water level is dangerously high in my display tank because my overflow teeth seem to be too thin for this much turnover.

 

The overflow teeth in my sump handled the increased flow with no change to the water level, but the display tank overflow teeth are much thinner and therefore need to be modified.

 

I have a split loc-line return line, and to temporarily fix the problem I ran one of the returns back into the overflow box to cut the turnover by 50% (close to the original 250 gph rate).

 

My question is this: Does anyone have advice on how to increase the width of the teeth in an acrylic overflow that is attached to a tank?

 

I have looked up a bunch of videos on how to cut acrylic, all of them have me worried. I wanted to see if anyone else here has had to tackle this problem. There is no easy way to remove the acrylic overflow part itself, it is thoroughly siliconed to the glass overflow box, so I will have to perform the modifications while the part is on the tank. The tank and overflow is a custom build by glasscages.com, I attached one of their stock photos that closely resembles the overflow on my tank.

 

The best (scary) plan I can think of is this:

 

1) Add a filter sock to the drain in my sump

2) Carefully drill out each tooth to a wider diameter with a cordless drill

3) Keep my return pump on so that tank water is running over the teeth as I'm drilling (to cool them)

4) Catch the drilled out acrylic from the filter sock on the drain (least of my worries)

Consider making the teeth longer but the same width, too. That may help. Plug your power tool in to a GFCI receptacle or buy a plug in GFCI. Preferably use a battery powered power tool - your cutter will be in the water if you do what you propose; it will spray everywhere and may get in to the tool.

 

I would strongly recommend removing the box to cut it - you'll get a neater job and safer!

 

Good luck with the project!

[StevieT]

Thanks Stevie, I'll make sure I get the right hardware. I assume I should still go slow to ensure the material doesn't melt?

 

 

Depends. Drilling = medium speed, it's a feel thing you'll figure it out pretty quick

 

Router or dremel = fast Melting isn't as much of an issue as you think if you have a sharp bit. And if you do melt a little it just picks off. The faster the tool is moving with acrylic the better it cuts as you are sending that cutting edge so many more times into the material.

[jservedio]

Power tools + salt water is a bad idea. Ever use a dremel or router on a wet surface? It makes a HUGE watery mess. With a router or dremel water is going to be shooting all over the place - you do not want to be cooling your tools with a highly conductive fluid. GFCI might save you from electrocution, but you will still ruin your tools.

 

If you are bent on actually doing that with water in the tank, you need to use a very, very low speed bit to avoid having water all over the place (including the tool).

 

Even with wider teeth, by increasing the flow going over the weir, you are removing the surface skimming effectiveness. The thinner the layer of water going over the weir, the better the surface skimming. You shouldn't be putting more water through an overflow than it is rated for.

 

You might be better off just entirely removing the acrylic cover or teeth and going with a toothless overflow

[StevieT]

Just drain down the water a bit so you are not cutting in the actual water, that is if you can't remove the overflow which is the best option anyway. Your pumps, heaters etc are underwater. No one said the tool needs to be in the water

[jservedio]

Just drain down the water a bit so you are not cutting in the actual water, that is if you can't remove the overflow which is the best option anyway. Your pumps, heaters etc are underwater. No one said the tool needs to be in the water

 

I was responding to OP who said he was going to leave the overflow running to cool the plastic as he cut. I was just pointing out that would be a terrible idea in terms of electrocution risk

[Gilligan]

I suppose a round rasp file would work OK, might give you a better result then free-hand with a dremel etc.

 

If you don't mind them a touch deeper, you can drill out the bottoms, then connect the notch with a hand saw etc.

[StevieT]

I was responding to OP who said he was going to leave the overflow running to cool the plastic as he cut. I was just pointing out that would be a terrible idea in terms of electrocution risk

 

Ahhhhhhh right. I thought he got that out of his head already as a terrible idea

[Sh55]

Thanks all for the advise.

 

I was never going to use a plug in tool, I was planning to use a cordless drill. I have room to make the teeth longer, maybe that is the best option.

 

I would like to remove the cover but it's thoroughly siliconed to the glass overflow box. Is there a trick to separating silicone?

 

I think a file is probably a better idea, it may take longer but it's definitely safer and easier to control. Hopefully I can find a thin file appropriate for acrylic.

[Sh55]

Update:

 

I was able to remove the black acrylic overflow cover. I used a wire snake to separate the acrylic cover from the glass overflow box. Basically I was able to force the snake down in between the glass/acrylic to effectively cut the layer of silicon between them.

 

The glass overflow box is actually a good water level and it's handling the flow nicely. The only issue is that I can now see my durso standpipe and return pipe in the middle of my aquascape . This brings me to my next question: If I don't want to cut the black acrylic box down to size, is there an easier way to black out the glass overflow to hide my plumbing?

For reference, here is an FTS from when the acrylic cover was still attached, as you can see it is right in the middle of my display.

[Gilligan]

You could cut a piece of black plastic from a tupperware lid etc.

 

Size it a bit narrower then the over flow. (,but wider then the teeth)

 

Measure from the top of the teeth down to an inch or so below the teeth.

 

Drill a couple of holes to attach some suction cups to. (left-overs from heaters etc.)

 

Stick it on the inside of the over flow and adjust as necessary.

 

The suction cups should keep the card suspended far enough away as to not interfere with the overflow action.

 

Easily removed for maintenance or if a better idea comes along.

[Sh55]

Thanks Gilligan,

 

Not a bad idea, I'll keep an eye out for a tupperware with a black lid. I wonder if there is another food safe (aquarium safe) plastic sheet I could use. I suppose one of those thin cutting boards could work.

[Gilligan]

I actually used plastic from a bin or tote not designed for food, the type for storage.

 

Just check the number stamped into the little recycling logo. I think "5" and "7" are reef safe, possibly others, you would have to check as you come across it.

[GTi]

If you can't find the right material in the right color, you could paint a cover - Krylon Fusion (after a week of curing time and a rinse off) is reef safe.

[Cali9dub]

Try a piece of thin starboard, possibly??