Tempered Glass + Acrylic = ???

Hello,
its been some time since i have last been active on the forums. And due to not living in a place of my own, being in college, and being broke, i have not done anything to get me much closer to having a SW tank. But at home i do have a 55 gallon fresh water tank that is made of tempered glass, and when i do start my saltwater tank (probably a 180), i plan on using the 55 as a sump. My question to you is using acrylic baffles in a tempered tank a bad idea? I remember reading on here that there is some conflict of using acrylic baffles in a glass tank but even so, is using acrylic in a tempered glass tank an even worse idea then a plate glass tank? Is using a tempered tank a bad idea period?
 

flower

Well-Known Member

Welcome back, the tempered glass just means you can’t drill it. The reason glass and acrylic won’t work is because silicone won’t stick to plastic and the pressure on the baffles make it come apart and not stick to the glass as it needs to.
Just go to the hardware store and have them cut you some glass to the size you need, someone on here told me to go to Lowes. Then just attach the baffles like you would if you were holding the tank together.
 
Quote:
Originally Posted by Flower http:///forum/thread/382674/tempered-glass-acrylic#post_3341314

Welcome back, the tempered glass just means you can’t drill it. The reason glass and acrylic won’t work is because silicone won’t stick to plastic and the pressure on the baffles make it come apart and not stick to the glass as it needs to.
Just go to the hardware store and have them cut you some glass to the size you need, someone on here told me to go to Lowes. Then just attach the baffles like you would if you were holding the tank together.
Oh, okay. I had the wrong impression about acrylic and glass. I thought you didnt want to use them together because the acrylic would swell/expand more then the glass and would cause the glass to crack (or shatter in the case of tempered). I have a real cool idea for my sump idea with this 55 gallon, and if i can use glass baffles i should be ok, but i plan on adding a QT to the sump. (Dont worry there would be no water exchange between the sump section and the QT section. I would use a HOB filter for the QT when in use, and the baffle dividing the sump from the QT would be as tall as the entire 55 gallon tank itself.)
Thanks for the quick reply flower.
PS New question, what would you say the minimum size for a QT is, would 10 gallons be enough as long as you did a water change weekly? My plan would be when i need to qt something, i would suck 10 gallons out of the sump into the qt to fill it, (no need to cycle), start up the HOB filter for the qt, and dump my fish in there (after appropriate acclimation). When im done qt'ing the fish i would just suck the water out of the qt into a bucket and dump it down the drain. Makes life easy for everyone right?
 

flower

Well-Known Member


Not a bad idea. As to what size it depends on the critter. I admit most new fish are small because they are young. I had a 10g for a QT/hospital tank.

As a hospital tank the 10g wasn’t good enough but as QT no problem. The only thing is keeping an eye on the new fish...under the tank may make keeping watch hard to do.

Oh and I remember something about acrylic expanding…you just had to make sure there was room. I have a glass tank and I need to get glass baffles for the reasons I mentioned.
 
I understand what you mean for viewing that under the stand might not be the best, but the space saving benefit is just amazing... maybe i will just make sure to have a clean enough sump (display sump) and build a stand with glass doors =P
Quote:
Originally Posted by Flower http:///forum/thread/382674/tempered-glass-acrylic#post_3341328


Not a bad idea. As to what size it depends on the critter. I admit most new fish are small because they are young. I had a 10g for a QT/hospital tank.

As a hospital tank the 10g wasn’t good enough but as QT no problem. The only thing is keeping an eye on the new fish...under the tank may make keeping watch hard to do.

Oh and I remember something about acrylic expanding…you just had to make sure there was room. I have a glass tank and I need to get glass baffles for the reasons I mentioned.
 

acrylic51

Active Member
If done correctly the silicone will keep the baffles in place.....I think some of the issues that have come about are due to the acrylic being cut to snug and when the acrylic "absorbs" water it cracks the tank. The acrylic needs to be scuffed good for the silicone to stick, but yes they can be used together...
 

flower

Well-Known Member
Quote:
Originally Posted by acrylic51 http:///forum/thread/382674/tempered-glass-acrylic#post_3341580
If done correctly the silicone will keep the baffles in place.....I think some of the issues that have come about are due to the acrylic being cut to snug and when the acrylic "absorbs" water it cracks the tank. The acrylic needs to be scuffed good for the silicone to stick, but yes they can be used together...

You can work acrylic and know just what to do to make it work. So there is no doubt in my heart that YOU could do it. Still I have to ask...I tried to use silicone to hold a maxi Jet power head to a plastic piece. This was back before I knew about Koralias that stay put with a magnet.
The vibration from the power head would eventually cause it to come loose from the piece..I was told silicone won’t stick to plastic. Don’t baffles have pressure from water flowing against it constantly, so that like the power head it is doomed to fail and come loose?
 

gill again68

Active Member
Quote:
Originally Posted by Flower http:///forum/thread/382674/tempered-glass-acrylic#post_3341599
Quote:
Originally Posted by acrylic51
http:///forum/thread/382674/tempered-glass-acrylic#post_3341580
If done correctly the silicone will keep the baffles in place.....I think some of the issues that have come about are due to the acrylic being cut to snug and when the acrylic "absorbs" water it cracks the tank. The acrylic needs to be scuffed good for the silicone to stick, but yes they can be used together...

You can work acrylic and know just what to do to make it work. So there is no doubt in my heart that YOU could do it. Still I have to ask...I tried to use silicone to hold a maxi Jet power head to a plastic piece. This was back before I knew about Koralias that stay put with a magnet.
The vibration from the power head would eventually cause it to come loose from the piece..I was told silicone won’t stick to plastic. Don’t baffles have pressure from water flowing against it constantly, so that like the power head it is doomed to fail and come loose?
The reason this didnt work is because the silicone won't stick to plastic. Before you cross your eyes..... The silicone works with the baffles, if done like acrylic says, is because the silicone is "holding" the baffle in place on either side of the baffle. Not sticking the acrylic to the glass but rather making a silicone channel for the acrylic to sit in. As far as the pressure on the baffles, if you look most of the baffles have either the same amount of water / force on both sides or not enough difference to really be a large problem.
So, yes, the silicone is a bad idea to try to use to "stick" plastic to glass but I think these are 2 very different things. I think that explains it.
Oh yeah almost forgot. I was one of those people that used acrylic for baffles and had water on the floor because it cracked my tank. As mentioned it was more of the acrylic being to snug and not having room for expansion that caused this issue. You can successfully use acrylic but you have to be careful. I recommend glass, and I would use the same thickness of glass so that it all moves together. In my opinion that is the best way and it takes one of those little voices out of my head that keeps me up at night wondering. Me and the other voices seem to be getting along now.
 
Well i sure dont want to end up like gill. So when i get to that point it sounds like glass is the way to go. Thanks for all your help guys. Now if only you could help me afford to start my tank, and move it in a year when i move out
 
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