A regular tank with slightly bow front?

[Tom]

Hi,

I just bought a new Perfecto 29g tank (30-1/4 L x 12-1/2 D x 18-3/4 H, unit: inch) with hood and light to prepare a fishless cycle. To my surprise, when I put the hood on top of the inner trim, there is a small gap between the trim and the hood in the middle of the tank. So I measure the tank again and got 12-1/2 inches on the right and left, and 12-3/4 inches in the middle. When I view the tank from the side, I can see the trim of the tank is slightly swollen. It is not a bow front tank, of course. I have another 29g tank, which has just finished cycle. I bought it used and don't know the manufacturer. It has the same measurement with swollen front. I didn't measure it before I fill it up with water. Does anyone have the same observation? One of my friends got a 45g or 55g(nor sure) and it doesn't have anything like that. Is that a defect tank? Should I return the tank and get a replacement? I'd better call Perfecto tomorrow.

From the top view

|<- 30 1/4 ->|
----------------------------
| | |
| | |
|12-1/2 |12-3/4 |12-1/2
----------------------------


--Tom

[NJ Devils Fan]

Fill it with water and if there are no leaks, then it is fine. I would say that something changed it's shape over time, such as heavy pressure.

[Tom]

Hi,

It's a brand new tank. There is no leak so far and not sure for the long run. I'd like to know if anybody has the same kind of "tank"? Is it really common?

--Tom

[paradigmcubed]

My tank has a similar bow, however it is working well. I wouldn't worry about it.

[Faramir]

I'm afraid I rather would worry about it. Glass bending under pressure is extremely fragile and unstable. It should not be so.

[paradigmcubed]

Wow, I didn't really think of that. I guess there really is no way to correct it?

[Faramir]

Drain it, and glue in a brace across the top - a strip of glass connection the back with the front.

By "glue", of course I mean silicone sealant.

[JSchmidt]

I'd call Perfecto. A quarter inch of bow over a 30" wide tanks seems like a lot. My Perfecto 55 (48" wide) doesn't bow a bit. (I just measured it.)

Jim

[Tom]

I just called Perfecto this morning. The service representative told me that it is quite normal to see the tank bow a little bit since the water pressure. She took the example of 30g and 10g tank in her office.

I would think it got something to do with the thickness/strength of the glass in the tank. Is it possible that you won't see this in the bigger tank because it uses thicker or even pressured glass?

Even though I don't worry as much as before I called Perfecto, I am still puzzled and would like to listen what people says in AC.

--Tom

[Faramir]

I think you're being had. The tank should not bow.

[superstein61]

well for peace of mind, since its a brand new tank, I would take it back and exchange it for another new one.

Tell the store it bows and you believe it is defective

[Tom]

HI,

I called the LFS where I bought the tank from. The owner assured me that the tank is normal. He said the tanks in the shop are bowed, too. He mentioned that he won't lose anything if I got the tank replaced, but I will probably get the same tank. Besides, he never saw any problem related to bowed tank in 20+ years. Some bigger tank won't bow since there is a center brace to re-enforce the trim and glass. It sounds reasonable to me.

Thanks for all the replies. I will start my fishless cycle tonight.

--Tom

[JSchmidt]

I'm not at home this weekend, but when I return I'll check my 30s. I have several without center braces. I'll see if they bow, too.

Good luck with the fishless cycle!

Jim

[Tom]

Jim,

Please let me know when you 've done your measurement. Thanks!

I printed out a couple of articles on fishless cycle a few days ago to prepare myself. Tonight I moved one of the filter sponge and some pea gravel from my cycled tank to the new tank. Tested the ammonia, add some ammonia, tested again and ....... My first day of fishless cycle. :)

--Tom

[NJ Devils Fan]

Glad to hear its underway. :)

Does it matter if a tank has a brace or not? My 72 doesn't have a brace. Is this cause for concern?

[Tom]

NJ Devils Fan,

The center brace will certainly help the glass to sustain the water pressure. As to how big the tank will need it, I don't have any information. Sorry. When I called LFS, he looked at one of his big display tank and found it bowed, too. What I got from Perfecto service representative is that if the tank does not "twist" or bow "too much", it should be fine. In my case, it's about 1/4 inch.

--Tom

[Raithan Ellis]

It's fine... with longer tanks and deeper tanks it's common to see a slight bow. 1/4" over 30" isn't much actually. If it bothers you that much, go trade it in a spend a few dollars on the next tank up that uses thicker glass.. like a 40 gal.

Faramir - Any background in basic physics or glassblowing will tell you that glass, even though hard to predict, it holds back constant pressure in a much more stable manner than a sudden impact... much like anything else in life. Totally normal for a tank over 2 feet long using 1/4" glass or so, holding that kind of pressure, espescially in the particular catagory of tanks that long that do not use a center brace.

Cheers,
Raithan O. Ellis

[Faramir]

Well, I wouldn't be at all happy with a visible bow. I am well aware that glass copes with constant pressure better than sudden jolts, but I still remain suspicious of glass under enough pressure to bow.

[125gJoe]

Originally posted by Faramir
Well, I wouldn't be at all happy with a visible bow........ The only 'bow' should be one designed that way. I don't think I'd trust it.. :confused:

[NJ Devils Fan]

My tank is a bow front, I'm just not sure if anything bad could happen if there isn't a brace.