150 tall visible distortion

[adam13]

I picked up a 150 gallon tank that I have been told is made by perfecto with one corner overflow. 48" by 24" by 30" I filled it with tap water for a leak test and it is all good.
However, when I look through the glass it seems to "bend" the back bottom and side edges from refraction. The apparent bend is considerable and noticeable. Is this normal? Does it mean the tank is defective? Thank you for your advice.

 

[scsinet]

All tanks, particularly large ones, bow to some extent. First and foremost, is all of the plastic edge banding and any cross bracing structurally sound? No cracks or missing parts, right?
If you place a known straight edge across the front of the tank, can you get an idea of how much deflection you are getting?
Where did you get this tank from?

 

[adam13]

The top and bottom braces and top and bottom rims are intact and not cracked at all.
Using a metal draftsmans "t" the front and back panels seem to bow out between 1/16" and 1/32".
The water level droped about 1/8" in the main tank per 24 hours and the stand was always dry. I am assuming that amount of loss is due to evaporation.

 

[scsinet]

48" glass deflecting 1/16" across it's width shouldn't be a problem.
Yeah, the level drop is almost certainly evaporation, especially this time of year and with the cold weather, the low humidity contributes big time. My reef tank at home is chewing through 6 gallons of water a day to evaporation.

 

[adam13]

Thanks, does anyone make a glass tank in 150 48"x24"x30" that does not cause any visual distortion when looking from the leading edge to the back?

 

[scsinet]

There is no such thing as a tank that does not bow. It's essentially impossible.
Acrylic is much clearer than glass, which may help, but acrylic is softer, so it may bow even more than glass.
Oceanic is one vendor that makes tanks with thicker glass than most, so it may bow less. The other alternative is to have a tank custom made with very thick glass. With the custom option, you can also use low lead (starphire) glass that is MUCH clearer than regular glass. With thick glass, the greenish tint that it has starts to become a real problem, so low lead glass is about the only way to go.
The reason I asked where your tank is from is because you either bought it used or you bought it from somewhere that sells rebranded perfectos, such as from Petsmart (Top Fin tanks). Supposedly, these rebrands are of a lesser build quality, so they might use thinner glass. I have a Top Fin branded perfecto 120g that uses 3/8" glass on the front panel. Unfortunately it's an oddball sized tank that only Perfecto makes, and I haven't seen any "genine" perfectos of this size to compare it to.
However, even thick glass is going to bow to some measure. The object you need is for it to bow little enough to cause a problem.

 

[adam13]

I got thank, stand, wet dry, canopy, and a coralife 48" 2x150 HQI 2x96 PC from craigslist for a deal too good to pass up on.
It says built by MG/CL on a sticker between the glass and the plastic support rim. The glass is the same thickness all around and is right between 7/16" and 1/2".
On a side note do you know the gph capacity of a 1" overflow tube? I think I am going to need to change the return to be an overflow also to have dual 1" overflows so I can exchange anywhere close to 10x turnover through the filtration.

 

[scsinet]

1" in perfect world conditions is about 600gph.
You can do the changes to the overflows you are talking about, but keep in mind that the "10x turnover" rule is A) arbitrary and B) misleading because the 10X is referring to the tank's turnover, not the filtration. It is not necessary to feed any more water through your filtration system than is necessary to support the filtration. IMO it's far easier, more reliable, quieter, and more flexible to size your filtration loop for what the filter needs, and accomplish your flow objective with powerheads. Powerheads can be positioned in more ways than inflows, and less flow through the filter will make it much quieter.

 

[adam13]

So if I am running 550 gph through my filter wouldn't it be quieter to run it down two 1" pipes each carrying half capacity than one at full capacity?