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(This post has been taken out of context from it's original text as a sticky for information re: acrylic vs. glass. Ger)
A couple of random thoughts ...
Glass vs. Acrylic
Glass Advantages: Less expensive ... until you enter the realm of Starfire; More difficult to scratch than acrylic; Allows maximum access to the top of the tank (except for crossbar/support); Cleaning of surfaces easier and less problematic; "Fixed" material ... glass won't "bow"/bend under longterm weight the way acrylic will; Durability ... withstands longterm "wear & tear" better than acrylic; Withstands exposure to heat ... MHs ... well.
Glass Disadvantages: Silicone seams are inherently less stable than chemically welded acrylic seams; Weight ... Bob's not kidding about needing the varsity offense to move a large glass tank around (although a 180 ought to be reasonably manageable) ... then there's associated shipping/transport costs; Glass edges are more dangerous to small children and careless adults; Glass breaks/chips with heavy impact, acrylic just cracks; Glass is difficult to DIY drill/modify without the right tools and experience; Refraction/transmission of light through glass less "true" ... subtle photography color/resolution implications; Conducts heat better (poorer insulation) than acrylic ... higher chiller operation costs vs. acrylic.
Acrylic Advantages: Very stable seams ... no leaking unless the manufacturers screw up (relatively rare); Lightweight; Rounded corners ... many people prefer this aesthetically; Less distortion of light as it passes through acrylic ... better "true" color and resolution for photography; Safer for small children and careless adults; Many more design/geometric options for tank design ... not really an issue for you; Easier DIY drilling/modification than with glass (... although even this can be problematic after the acrylic has begun to "move" ...); Better insulation than glass ... cheaper chiller operation costs.
Acrylic Disadvantages: Material degradation over time ... it WILL get scratched no more how careful you are; More difficult cleaning maintenance ... unattended coralline algae can actually grow into the polymer structure causing permanent scarring ... more specialized products required to maintain luster of outer surfaces; Less Durability ... much softer than glass, so it's easier to injure; "Fluidity" of Material ... acrylic moves over time, under weight. There will be a slight/noticeable (... up to ~1/32" ...) "bowing" of the viewing planes, as well as a potential distortion of the bottom (... mildly problematic when moving the system to a new stand ...); Potential for Bending /Distorting after prolonged exposure to heat source ... MHs or bad heater placement; The "Biggie" for me is this: Less Access through the top of the Tank ... I'm into exotic aquascaping & rock fabrication. Because acrylic tanks must have a top plane ... to minimize bowing/movement of the viewing planes ... what you can put into the tank is limited to the openings cut into the top plane. You can special order larger than average openings, but it's still a limiting factor.
Regarding sump size/volume ...
I didn't see any specification regarding how the water gets to the sump ... I'm thinking you're going with a built-in overflow box, yes?
If so, you might want to reconsider your sump size. When the power goes off, all of the water present in the tank that is above to bottom edge of the slots in a built-in overflow is going to gravity feed into the sump. Unless you enjoy flooding ... hehe ... I'm wondering whether or not the sump volume is sufficient.
My general estimate on the "empty volume" requirement for sump space is on the order of 2 - 3 inches of display tank height ... depending on how much water is being pumped through the display.
With a 180G tank, we're talking a range of:
@ 2": (72" X 24" X 2")/231 = 14.9G
@3": (72" X 24" X 3")/231 = 22.4G
So ... you're going to need ~15G to ~23G of empty volume sitting there waiting for the power to fail. I'm alittle concerned that your 36" X 18" X 20" is right there at the edge of what's required ... although technically it's inbounds. When you additionally factor-in convenient spacing of sump components (... space relationship between skimmer, ZeoReactor ... etc ...), ease of manipulating and removing/replacing those components and their plumbing & electrical, minimum water height in the sump to prevent your return pump(s) from sucking air (depending on how its plumbed), ... AND the ability to raise the sump's "standing" water level in order to influence skimmer performance towards wet skimming (depending on skimmer type) ... I'm wondering whether or not a larger sump design is in order. Just a thought.
A couple of random thoughts ...
Glass vs. Acrylic
Glass Advantages: Less expensive ... until you enter the realm of Starfire; More difficult to scratch than acrylic; Allows maximum access to the top of the tank (except for crossbar/support); Cleaning of surfaces easier and less problematic; "Fixed" material ... glass won't "bow"/bend under longterm weight the way acrylic will; Durability ... withstands longterm "wear & tear" better than acrylic; Withstands exposure to heat ... MHs ... well.
Glass Disadvantages: Silicone seams are inherently less stable than chemically welded acrylic seams; Weight ... Bob's not kidding about needing the varsity offense to move a large glass tank around (although a 180 ought to be reasonably manageable) ... then there's associated shipping/transport costs; Glass edges are more dangerous to small children and careless adults; Glass breaks/chips with heavy impact, acrylic just cracks; Glass is difficult to DIY drill/modify without the right tools and experience; Refraction/transmission of light through glass less "true" ... subtle photography color/resolution implications; Conducts heat better (poorer insulation) than acrylic ... higher chiller operation costs vs. acrylic.
Acrylic Advantages: Very stable seams ... no leaking unless the manufacturers screw up (relatively rare); Lightweight; Rounded corners ... many people prefer this aesthetically; Less distortion of light as it passes through acrylic ... better "true" color and resolution for photography; Safer for small children and careless adults; Many more design/geometric options for tank design ... not really an issue for you; Easier DIY drilling/modification than with glass (... although even this can be problematic after the acrylic has begun to "move" ...); Better insulation than glass ... cheaper chiller operation costs.
Acrylic Disadvantages: Material degradation over time ... it WILL get scratched no more how careful you are; More difficult cleaning maintenance ... unattended coralline algae can actually grow into the polymer structure causing permanent scarring ... more specialized products required to maintain luster of outer surfaces; Less Durability ... much softer than glass, so it's easier to injure; "Fluidity" of Material ... acrylic moves over time, under weight. There will be a slight/noticeable (... up to ~1/32" ...) "bowing" of the viewing planes, as well as a potential distortion of the bottom (... mildly problematic when moving the system to a new stand ...); Potential for Bending /Distorting after prolonged exposure to heat source ... MHs or bad heater placement; The "Biggie" for me is this: Less Access through the top of the Tank ... I'm into exotic aquascaping & rock fabrication. Because acrylic tanks must have a top plane ... to minimize bowing/movement of the viewing planes ... what you can put into the tank is limited to the openings cut into the top plane. You can special order larger than average openings, but it's still a limiting factor.
Regarding sump size/volume ...
I didn't see any specification regarding how the water gets to the sump ... I'm thinking you're going with a built-in overflow box, yes?
If so, you might want to reconsider your sump size. When the power goes off, all of the water present in the tank that is above to bottom edge of the slots in a built-in overflow is going to gravity feed into the sump. Unless you enjoy flooding ... hehe ... I'm wondering whether or not the sump volume is sufficient.
My general estimate on the "empty volume" requirement for sump space is on the order of 2 - 3 inches of display tank height ... depending on how much water is being pumped through the display.
With a 180G tank, we're talking a range of:
@ 2": (72" X 24" X 2")/231 = 14.9G
@3": (72" X 24" X 3")/231 = 22.4G
So ... you're going to need ~15G to ~23G of empty volume sitting there waiting for the power to fail. I'm alittle concerned that your 36" X 18" X 20" is right there at the edge of what's required ... although technically it's inbounds. When you additionally factor-in convenient spacing of sump components (... space relationship between skimmer, ZeoReactor ... etc ...), ease of manipulating and removing/replacing those components and their plumbing & electrical, minimum water height in the sump to prevent your return pump(s) from sucking air (depending on how its plumbed), ... AND the ability to raise the sump's "standing" water level in order to influence skimmer performance towards wet skimming (depending on skimmer type) ... I'm wondering whether or not a larger sump design is in order. Just a thought.
Bob
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