Modular Marine 1600gph overflow install question

[john fidler]

Hi,

Just received this overflow for my (planned) 75 gallon tank and have a question on drilling the tank for the installation. The tank is a standard trimmed tank. The instructions say to mount the external box as high as possible to keep the water line above the trim. The package included a template but the instructions also warned about making sure there is enough clearance to be able to install and I guess remove the internal skimmer box and its removable cover so as to not interfere with the interior tank trim.

After measuring about a dozen times I came up with providing a 1/8" clearance between the top of the template and the inside bottom of the trim inside the tank. This looks like it would still enable me to keep the water line above the trim.

Has anybody had any experience with installing this kind of overflow on a standard trimmed tank? Am I on the right path?

Also, the instructions seem to say to position the external box to mark the holes for drilling. Seems like it makes more sense to position the template on the inside of the tank and mark the holes for drilling. Is there anything wrong with drilling the glass from the inside of the tank or does it have to be from the outside? If so, not sure how I can accurately mark the holes and drill from the outside using their instructions since it seems tough to get a marker inside the external box to mark the hole locations like it says in their instructions. Seems easier to use the template inside the tank.

Any help or advise is appreciated. Their website wasn't much help.

John

[Mysticalknight]

I’ll be honest, I am having a hard time visualizing what you are saying. That being said, I have a modular marine overflow on my 40 breeder, and I followed the instructions that he provided and all worked out as it was supposed to


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[john fidler]

Thanks Mystical,

Since you have installed one of these, I guess my bottom line question is (assuming you installed on a standard 40g tank with trim), how much of a gap did you leave between the top of the interior skimmer box (with lid) and the underside of the tank trim?

Or, if you remember or did it this way, did you butt the included template against the underside of the tank trim on the inside of the tank when you drilled your holes, or did you leave a gap (say about 1/8") between the template and the underside of the tank trim inside the tank?

Hope that clarifies my question and thanks for any response.

John

[Bent]

I have the same overflow in the same size tank.

The top of mine is butted right up against the underside of the top trim.

[john fidler]

Bent,

Are you talking about the inside skimmer box being up against the underside of the interior tank trim? If so, you can still remove the skimmer box cover?

Sorry for being so detailed, but don't want to make a mistake when drilling the hole locations.

Thanks, John

[ca1ore]

Remember that with all these internal skim boxes, the lowest water level will be at the bottom point of the cut slots. I always position it so that the bottom of said slots are exactly level with the bottom edge of the tank trim. That way, regardless of the amount of water you put through it, you will never see the water line. The cover that MM provides for the internal skim box sits slightly higher than the top edge of the box, so you need to have 1/4' of clearance below the underside of the top lip.

[john fidler]

Thanks ca1ore,

That's what I was looking for. I had figured about 1/8" below the tank lip, but maybe I'll do 1/4". I am aware of the bottom of the teeth, and getting the water line above the bottom of the tank trim. Hence all my longwinded questions.

I'll check all the measurements again. I think using a 1/4" gap puts the bottom of the teeth about 1/8" below the trim. (Using 1/8" put the bottom of the teeth level with the bottom of the trim.) Either way, I think the water line would end up hidden.

John

[Mysticalknight]

Sorry for the delay in response, don’t remember exactly how I did it, but maybe these pics will help


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[JMetaxas]

How does this compare to the Synergy overflow?

John

Originally Posted by john fidler

Hi,

Just received this overflow for my (planned) 75 gallon tank and have a question on drilling the tank for the installation. The tank is a standard trimmed tank. The instructions say to mount the external box as high as possible to keep the water line above the trim. The package included a template but the instructions also warned about making sure there is enough clearance to be able to install and I guess remove the internal skimmer box and its removable cover so as to not interfere with the interior tank trim.

After measuring about a dozen times I came up with providing a 1/8" clearance between the top of the template and the inside bottom of the trim inside the tank. This looks like it would still enable me to keep the water line above the trim.

Has anybody had any experience with installing this kind of overflow on a standard trimmed tank? Am I on the right path?

Also, the instructions seem to say to position the external box to mark the holes for drilling. Seems like it makes more sense to position the template on the inside of the tank and mark the holes for drilling. Is there anything wrong with drilling the glass from the inside of the tank or does it have to be from the outside? If so, not sure how I can accurately mark the holes and drill from the outside using their instructions since it seems tough to get a marker inside the external box to mark the hole locations like it says in their instructions. Seems easier to use the template inside the tank.

Any help or advise is appreciated. Their website wasn't much help.

John

[Syntax1325]

I have one of these as well. The inner box is about 1/2inch higher than the outer box. I have an Aqueon 180 and I placed the top of the outer box up against the trim of the tank. This position hides the water like and leaves plenty of room for removing the cover to the interior box for cleaning.


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[Bent]

Originally Posted by john fidler

Bent,

Are you talking about the inside skimmer box being up against the underside of the interior tank trim? If so, you can still remove the skimmer box cover?

Sorry for being so detailed, but don't want to make a mistake when drilling the hole locations.

Thanks, John

I’m not sure I understand the question.

[Syntax1325]

If you have an Aqueon tank then the trim is the same for the 75 gallon and 180. I pushed the exterior box to the bottom of the trim

IMG_0992.jpg

Here’s a look ok at the interior, plenty of room to remove the cover if needed.

IMG_0993.jpg

Cleaning the teeth with this makes removing the cover unnecessary.
IMG_0994.jpg



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[john fidler]

Syntax,

Thanks, I was wondering if you could just push the outside box up as far as it would go against the bottom of the outside trim and still have clearance to remove the weir cover inside. The measurements I was taking seemed to indicate that I would have to lower the box a little to be able to do this, but I guess I'm wrong.

If I may, the instructions also say "when you have your exterior box positioned where it needs to be, use a permanent marker to trace the holes from the inside of the overflow onto the aquarium glass." How do you do this? I can't fit a marker in the box to be able to trace the holes. I was going to use the template on the inside of the tank to position the holes and mark them, but someone else told me it's better to drill from the outside. Or am I overthinking this whole thing?

Thanks, John

[Syntax1325]

Double check your measurements. Measure the height difference between the outer and inner boxes... I can't remember but I think it's an 1/2 or 1 inch. measure that distance from the bottom of the inner trim and you'll have an accurate reference point. Then measurement from the top of the cover of the internal box to the bottom of the interior trim is 3/8"... it's close but it works. If you want to create a wave in your tank then you may want to drop the exterior box a bit... the water level is fairly high, I prefer that though.

I was able to take a sharpie marker and angle it to make the circle, you should be able to do this as well.

I would drill from the outside just in case the hole chips as the bit pushes through. You want to the exterior hole to be perfect.

[Syntax1325]

Here’s a picture of the water level. Actually, it’s perfect.


IMG_0995.jpg


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[john fidler]

Syntax,

I think I have a newer version of their overflow. The interior skimmer box and outside box are about the same height, certainly not a 1/2 to 1 inch difference in height (maybe a 1/16"). So I think it makes my scenario a little different. I have put in the question to Modular Marine so I'll see what they say.

I'll try doing what you say again relative to the angling the marker to draw the circle.

Thanks again.

[Syntax1325]

Got it... I'm glad that you figured that out before drilling! My box is about 18 months old. I didn't realize the design changed so much. Good luck !

[john fidler]

Syntax,

Yeah, they changed the design to make the inner and outer boxes the same height. On their ebay site, they say "Rear box has new notched design to fit over trim so both boxes are mounted at the same height!" and that "One main advantage of our design that no one else has is if you close your drain valves our exterior box will not overflow. This is because our exterior plumbing box mounts at the same height as the skimmer box. All the other designs on the market have an exterior box that is mounted well below the skimmer box so if you shut the drain valves the exterior box will overflow."

Albeit, I can't think of why one would shut all of their drain valves, or if someone did, I would assume they've also turned off the return pump.

[john fidler]

Maybe the old design would overflow if you closed the drain lines because there would be slow seepage from the display tank skimmer box the the outer box, since the connection is not sealed?

[Syntax1325]

Old design could overflow if your main syphon, open channel and emergency become 100% blocked. I can't fathom how that could happen.

[john fidler]

Thought about this a little more. I guess there may be a scenario where you shut off your return, close all the drain pipe valves and remove the skimmer box for maintenance purposes. With the new design then, the outer box would not overflow due to a higher water level coming from the tank when you remove the skimmer box. This would also presume that your sump couldn't handle this excess amount of water if you kept the drain valves open.

I think???

[john fidler]

Anyway I also heard back from Modular Marine. They said I was correct in leaving a small gap at the top of the skimmer box to remove the lid (i.e., lowering the outisde box slightly to account for this.

Also questioned how to get into the outer box to mark the holes with a sharpie. They responded that they make mini-sharpies that would fit. Didn't know this. My bad, but appreciated their quick response.

[ca1ore]

Originally Posted by john fidler

Maybe the old design would overflow if you closed the drain lines because there would be slow seepage from the display tank skimmer box the the outer box, since the connection is not sealed?

Does anyone even put valves on an emergency? I can see no reason for it. My MM is something of a 'hybrid'. Doesn't have the removable skim box, but the external box is at the same height. The connection is sealed though so no seepage like with the removable box (which is why I opted against it).

[Modular Marine]

Originally Posted by john fidler

Maybe the old design would overflow if you closed the drain lines because there would be slow seepage from the display tank skimmer box the the outer box, since the connection is not sealed?

This is correct with removable weir designs. Our older design with a lower plumbing box does not have this issue because they are sealed and water can not pass through anywhere but the skim box teeth.

[Blue Tang Clan]

Originally Posted by Modular Marine

This is correct with removable weir designs. Our older design with a lower plumbing box does not have this issue because they are sealed and water can not pass through anywhere but the skim box teeth.

Hi Modular Marine -- I am getting a new display tank from Custom Aquariums and they said that many overflow boxes (including MM) do not work with their framing because the box with hit the frame. The result is that they have to mount the overflows lower on the glass, which lowers the water line in the tank.

From a design perspective, is there any reason to think that this might be the older design vs. the new one where both boxes are the same height?

I want to go with MM for an overflow, and I'm almost choosing my tank manufacturer around it!!