PVC bottom tank - how safe?

iReefer12 · Aug 16, 2022

I’m getting quotes on a large Glass tank and 1 manufacturer has suggested a PVC bottom to the tank, I like the idea, but I have a lot of concerns, I didn’t think PVC and glass bond to each other? Does anyone know more about this and can speak to the technique used and offer some insight, can I trust the seal for 10+ years?

Lost in the Sauce · Aug 16, 2022

I think they are offering a PVC bottom cover. To protect the glass. Not replace it. That's a question. You should probably ask them though....

mfinn · Aug 17, 2022

I have a tank from a local tank builder that has pvc on the bottom. But as previously posted, it's just a cover to protect the glass bottom. It also have pvc corner guards. These features came stock. I wouldn't have ordered them. I've never had a issue with a glass bottom tank in nearly 60 years of keeping fresh and saltwater fish.

Mike konesky · Aug 17, 2022

Planet made an 8 foot with a PVC bottom. No glass on bottom, just PVC. Crystalline I believe was the model. Awesome tank.

iReefer12 · Aug 17, 2022

Yeah, that’s the style I’m talking about. Yeah, just looking for more info, how do they bond the pvc and glass? How can that be done and safely.

I like that it makes the tank weigh less, easier to move in etc. but scared of the risks.

Mike konesky · Aug 17, 2022

iReefer12 said:
Yeah, that’s the style I’m talking about. Yeah, just looking for more info, how do they bond the pvc and glass? How can that be done and safely.

I like that it makes the tank weigh less, easier to move in etc. but scared of the risks.

Might call Planet and ask them. The one I'm talking about came in as a teardown and was used as a LFS display for a year before being sold a few months ago. Based on the size of the sps colonies I'd guess the tank was at least 5 years old before it got to the shop. I don't remember looking at the lower seam to see what the adhesive was. PVC was thinner than the glass 3/8" or 1/2" probably. Looks like they use 1" now. Was really nice working in it with the feeling of added safety.

TL1 · Aug 17, 2022

One of the local LFS has a 1200 gallon PVC bottom. Been running fine for a decade or more. Just make sure the bottom is adequately supported - when he first installed the tank the bottom bowed downward almost a foot at the center.

biecacka · Aug 17, 2022

AGE has been doing it for years on tanks they build. However, they don't share the knowledge of how they bond together. But many people have had success with their tanks.

corey

mtraylor · Aug 18, 2022

Yeah AGE has been doing forever. I have custom AGE tank, and I did not get the pvc bottom. They pushed hard for it but I did not want to have it.

Nothing wrong with it. I just didn't see any benefit. So I wanted to keep it simple

thatmanMIKEson · Aug 18, 2022

Never heard of this pretty cool

whitelightning77 · Apr 24, 2023

TL1 said:
One of the local LFS has a 1200 gallon PVC bottom. Been running fine for a decade or more. Just make sure the bottom is adequately supported - when he first installed the tank the bottom bowed downward almost a foot at the center.

Not sure if this thread is still active. But this comment caught my attention. I have a used 300 gal AGE tank I'm trying to set up and am having a time leveling it. The bottom pvc is bowing down a bit, about 1/2" which doesn't let the rim of the tank sit flush against the plywood top of my stand. Will the added weight of the water push everything down leveling the tank?

Enderg60 · Apr 24, 2023

My tank from MRC is a hybrid. PVC bottom, Glass sides, Acrylic eurobrace.

Yes it works, and Yes its worth it. No worries of falling rocks cracking the bottom. Can be drilled however you want with ease. Textured bottom wont let frags blow away as easy. Plastic bottom promotes coraline growth. Only downside is its hard to scrape stuff off the bottom.

My tank was made by milling a groove around the bottom for the glass to sit inside. Id never seen that before but it definitely makes the joints WAY stronger.

Its purely buyers choice but I wouldnt worry about it.

whitelightning77 · Apr 24, 2023

Thats how mine is in a sense. It has a top and bottom rim. The pvc panel is routed on the edges to the side panels sit inside the groove of the pvc and the perimeter rim.

Any insight in regards to the pvc bowing a little when its empty?

Enderg60 said:
My tank from MRC is a hybrid. PVC bottom, Glass sides, Acrylic eurobrace.

Yes it works, and Yes its worth it. No worries of falling rocks cracking the bottom. Can be drilled however you want with ease. Textured bottom wont let frags blow away as easy. Plastic bottom promotes coraline growth. Only downside is its hard to scrape stuff off the bottom.

My tank was made by milling a groove around the bottom for the glass to sit inside. Id never seen that before but it definitely makes the joints WAY stronger.

Its purely buyers choice but I wouldnt worry about it.

Enderg60 · Apr 25, 2023

whitelightning77 said:
Thats how mine is in a sense. It has a top and bottom rim. The pvc panel is routed on the edges to the side panels sit inside the groove of the pvc and the perimeter rim.

Any insight in regards to the pvc bowing a little when its empty?

When starting it up it was filled and emptied at least 5 times. I have seen zero bowing at all, but I have a well made steel stand.

My only real gripe is that a little bit of PVC glue dripped on it and now I have an ugly spot I have to wait for algae to cover.

GARRIGA · Apr 27, 2023

Saw Planet on a show video with this design and it intrigued me to the point I’m wondering if they can build it with bottom, rear and sides with just the front being glass.

Going to be lighter. Only need to worry about scraping coralline off the front glass. Easier to drill back and bottom. Only the front glass can crack and that could be made thicker. Just not sure how long the seals last. Why I was thinking all acrylic but this might be a better hybrid option.

As for bowing on the bottom. Thinking braces can be added as done with large tanks. Stand can be built to hide this. Extruded alluminum can be built with several braces spanning the bottom and approach I'd take regardless off tank I end up with. Stability being the focus vs just looks. Especially with larger tanks. Finding my inhabitants on the floor not desired plus all that water going to ruin the floor and get me divorced.

Blue Spot Octopus · Apr 27, 2023

We had a club member buy a used one but he lives in a hot area during the summer and he left the tank outside while he was working inside the house, the tanked failed/broke because of the heat.

whitelightning77 · Apr 27, 2023

Interesting

zoomonster · Apr 27, 2023

TL1 said:
One of the local LFS has a 1200 gallon PVC bottom. Been running fine for a decade or more. Just make sure the bottom is adequately supported - when he first installed the tank the bottom bowed downward almost a foot at the center.

I've seen that sort of story before from users and don't think I would ever not do a glass bottom. I made the mistake of putting PVC boards on my boat trailer. Guess what they sag. Protector sounds like a good idea though. I also would not buy a stand that didn't have a PVC liner. I paid a little extra on mine, but it completely covers the inside bottom and holds up to 3" of water.