# DIY All Glass Tank, Safe Water Height/Filtration



## imusuallyuseless (Dec 28, 2005)

So I built an all glass 40G column tank. 36" tall, 16x16 base. I've test filled it outside for over a week w/no visible issues. Butt seams look good, but I was not able to properly spread the silicone on interior seam between the base and back wall due to how tall and narrow it is. The walls are 3/8" thick tempered glass, base is also 3/8", not sure if tempered.

Anyway, I'm kind of at a stand still before bringing it into the house. Although I test filled it at full height, I'm not sure how safe it is long term considering how tall it is. Looking for opinions from others on what a reasonable fill height would be on this tank long term???

Which kind of leads me to my next issue of filtration. I had in my head that I wanted this to be the clean rimless look tank, so I was considering having a pseudo undergravel filter. Basically, a pond filter in the bottom~10" of the tank, covered by drip plate, then screen material, then substrate. This would leave the top of the tank clean and open, but drastically reduces the water column height, which is fine, if filling to top, but not so much, if going w/lower fill height due to safety factor.

Other thought is some kind of overhead filter...???

I know I'm kind of long winded here, but I've been thinking about this for several weeks w/no solution. Any thoughts or opinions are appreciated.


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## Old Newbie (Feb 18, 2017)

According to this diy tank building calculator, http://www.garf.org/tank/buildtank.asp , you should not go higher than 24" with 3/8 glass. Any value above 24" that I plugged in indicated 1/2" glass


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## imusuallyuseless (Dec 28, 2005)

That was my initial thought as well, just hoping someone out there has further input as I don't know whether the tempered glass factor changes anything...


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## Deeda (Oct 12, 2012)

Your pics aren't working because of the new Photobucket policy regarding 3rd party linking so you may want to use another photo hosting website OR you can link pics directly to the forum using the Full Editor.


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## Old Newbie (Feb 18, 2017)

Deeda said:


> Your pics aren't working because of the new Photobucket policy regarding 3rd party linking so you may want to use another photo hosting website OR you can link pics directly to the forum using the Full Editor.


That's weird, I can see the pictures.


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## imusuallyuseless (Dec 28, 2005)

Hopefully this works, I'd be happy not to have to use photo bucket


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## imusuallyuseless (Dec 28, 2005)

Almost done with stand...


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## joselepiu (Jul 22, 2017)

are you going to leave the straps when you take it inside?... :? :? :? 
maybe that is what it is holding it together... :roll: :roll: :roll: 
just my opinion... :roll: :roll: :roll:


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## imusuallyuseless (Dec 28, 2005)

The straps played no part in holding it together. They were setup in a way to prevent it from swaying since it was being water tested outside in windy conditions on a temporary stand, which meant it was extremely top heavy. Thanks for your opinion =D>


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## joselepiu (Jul 22, 2017)

even if it was minimal, i think the made a lit bit of compressing the glass sides together from i case in the pic...


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## Deeda (Oct 12, 2012)

I have no experience with DIY tank building but do agree with Old Newbie's link suggestion on thicker glass for a taller tank.

Your pic showing the stand build also gives me great pause as to the stability since the column support is considerably smaller than the tank bottom. It looks as if it won't take much lateral movement to knock that tank over easily.

As far as viewing Photobucket links, some people can still see them but it seems a hit or miss event. I have been contacted by them that my pics are no longer visible so maybe once they catch up with a user, they then disable the links unless you are a paying customer.

I can view your attached pics that you posted through the C-F forum option.


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## gillmanjr (Jan 27, 2017)

If I were you I would add PVC angle around the bottom, at a minimum (if not the sides too). 3/8" tempered glass is strong enough to support the water load but its the seams that are questionable. I wouldn't count on 3/8" silicon seams holding together under a 36" high water column, not in the long term.

Heres what I am talking about, this is 1/4" thick stuff, to be honest 1/8" would probably be strong enough...

https://www.interstateplastics.com/Pvc- ... 0011745-4p


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## imusuallyuseless (Dec 28, 2005)

Feel free to delete the photobucket links as I'm fine going w direct uploads. I understand your concern w the stand, but I've built unconventional stands before w no issues. If I had kids or dogs I would be rethinking it. Also, consider the fact that although the bottom pane of glass is larger than the column footprint, the actual walls of the tank are not.

Anywhooo, I'm familiar w the garf plans, I used them when I built my first 2 DIY glass tanks many years ago. Typically I wouldn't push the envelope on the glass, but I feel like >24" is potentially doable given tempered and its soooooo narrow both length and width.

gillmanjr, thanks for input. Those pvc angles look interesting. As of right now I'm considering making a sleeve w 1x or 3/4" plywood going around the bottom 8" or so of the tank.

Anyone think it would provide enough support to be worthwhile?


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## gillmanjr (Jan 27, 2017)

I wouldn't use wood. There are too many imperfections. I would want something manufactured that I know is perfectly straight and smooth and I would silicon it directly to the glass. But thats me.


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## joselepiu (Jul 22, 2017)

gillmanjr said:


> I wouldn't use wood. There are too many imperfections. I would want something manufactured that I know is perfectly straight and smooth and I would silicon it directly to the glass. But thats me.


+1...
plus with time it will most likely it get wet and you know how wet wood reacts...
imo... :fish: :fish: :fish: ...


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## imusuallyuseless (Dec 28, 2005)

Certainly something to consider. I suppose my thought is that wood has a surface "even /flat" enough to be relied upon to be used on plywood tanks where it is also in contact w the glass so what's the difference? In that same context, it could also be sealed so I fail to see how spilling occasional water will be an issue. My thought for "sleeve" would entail it being glued and screwed on corners, possibly w metal brackets incorporated. A slight gap between wood and glass all around being filled w silicone to address issue of the imperfect wood to glass surface difference.

I will also be checking a glass shop tomorrow to see if 4 strips of glass can be found at a reasonable price to be used instead.

My initial question remains. Would it be worth doing in the sense of safely being able to make the final fill height >24"???


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## BC in SK (Aug 11, 2012)

imusuallyuseless said:


> final fill height >24"???


The standard 90 gal. is made of 3/8's glass. It is 4 ft long and 24" deep on the inside (so that is excluding the false bottom).
Your standard 125 gal. is also made of 3/8's glass. It is a 6 ft. tank and about 22" deep on the inside.
Those tanks are made of plate glass. Tempered should be even stronger then plate glass, though there are different strengths of tempered glass.
A 16" long tank should have greater strength then a 4 ft. span. Brace the seams with either glass or wood and I can't see why it wouldn't have a decent safety margin if your intention is to fill it up to around 24".


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## gillmanjr (Jan 27, 2017)

Four strips of glass will help if you silicon them along the whole bottom and sides, but they aren't going to give you anywhere near as much structural reinforcement as angle.


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## imusuallyuseless (Dec 28, 2005)

The intention is to go higher than 24", possibly 30.

I have been seriously considering the angle, I even have 1/8" angle steel that would do the trick, however I think it would really kill the aesthetics of the tank. Since only 16" long, adding anything to the vertical seams all the way up would look terrible imho.

Usually I'm all about function over form, but in this case I'm very much concerned about the look of the tank being simple. I'm still open to any more opinions on structural reinforcement of the bottom.

If there is no real consensus, I suppose I'll have to settle for 24 and build an overhead filter in the top 12" of dead space, which is truly not what I want...


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## gillmanjr (Jan 27, 2017)

imusuallyuseless said:


> The intention is to go higher than 24", possibly 30.
> 
> I have been seriously considering the angle, I even have 1/8" angle steel that would do the trick, however I think it would really kill the aesthetics of the tank. Since only 16" long, adding anything to the vertical seams all the way up would look terrible imho.
> 
> ...


Honestly, I think if you just run the PVC angle around the bottom seams you would be OK. As long as you cut it correctly for the corners it will provide structural reinforcement for the entire tank, including the vertical seams. I think you'll be OK as long as you cut it carefully and fill it with silicon. I would also use PVC cement to glue the edges of the angle together at the corners. PVC cement chemically melts the plastic together creating a single piece. If you did it properly you could literally create a square PVC angle frame around the base of the tank, it would be tremendously strong. It would have to be cut perfectly though. Given the fact that you've built this tank yourself I think you are capable of doing it.

However, I would also do something to reinforce the top of the tank (to keep it from separating at the top). You could either do another separate PVC angle frame around the top, or you could use an additional piece of glass and silicon it to the top to create a "euro" style frame-less top (kind of like an acrylic tank). You could use very thin glass for this, 1/4" would work. And it doesn't have to be tempered.


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