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What is your oldest tank? I have several used ones, and today one one of my newer pet-store-sale ones a few years old started leaking at the bottom. It's a 29 so while it's been an ordeal, if my 55 or 90 leaked, I would be in a world of panic.

78 years but it's an outlier! I find it's more about how often they are moved or drained and filled.

Jools

Jools wrote: 06 Oct 2023, 17:00 78 years but it's an outlier! I find it's more about how often they are moved or drained and filled.

I think you are right. The only ones I have had leak are ones which have been moved lots. My 125 gallon (6'x18" footprint) is now on it's 19th year in this house and the silicone is visibly deteriorating a bit on the inside (from plecos chewing) but othewise it took as good as new. But it's never been moved. We bought the house and then the tank and it's sat in the same place for 19 years.

I have a 90 gallon I bought new in 2004 and a few years after that I bought a bunch of 40 breeders and 20 gallon tanks used and were around 10 years old when I got them. Never had a leak with any of them so far.... but some other "newer" tanks I have gotten over the years have leaked.

Take care,
Chuck

I am wondering if I can reuse the wood stand; the top is fine but inside the bottom where the shelves are, there is some water damage along the center of the piece.

Taratron wrote: 07 Oct 2023, 01:21 I am wondering if I can reuse the wood stand; the top is fine but inside the bottom where the shelves are, there is some water damage along the center of the piece.

Is the stand solid wood? plywood? Particle board?

Cheers, Eric

solid wood it feels like. it's heavy!

Assuming the tanks are glued together with siliicone glue, please realize this was invented in 1970 or so, and the glue has seen a lot of improvements. The current glue lasts longer than the privious ones

However, apart from old age, I wonder whether vibrations also hurt these tanks. I have repaire quite a few of them (remouve the old glue, and glue in a new strip in order to be certain the tank is kept together by new, fresh, clean surfaces). The repairing itself is not the problem, emptying the tank is.

I currently have a tank, ~ 15 to 20 years old which measures 290 * 80 * 60 cm, and is leaking above 45 cm. I will have to empty it, that is relocate the fishes and than the rest is relatively easy.

This tank was a gift from a friend's wife. She received it as a child in 1975. Still running after nearly 50 years. It is a paludarium now as it leaks at the very top if fully filled.
-Shane

Copying the trend from public aquarium, I've started using PU for my new aquarium builds and re-builds as the technology provides better tensile strength, gap bridging and longevity over silicone. Especially for larger deeper tanks including glass - glass, glass - steel, glass - acrylic, etc. The best part is new PU strongly and safely sticks to old cured PU reliability which would make further repairs or future tank extensions very easy. There are more and more specialised and hybrid PU's being produced by more and more manufacturers which can make selection confusing but all have specification sheets.

Going on about 25 years on my oldest tank, in and out of use and gone through a number of moves. Thicker glass on older tanks seems to help give them and their seams longer life.

aquaholic wrote: 12 Nov 2023, 01:29 ... I've started using PU for my new aquarium builds and re-builds

This is interesting, is PU = polyurethane? Which product(s) are aquarium safe?

As an aside how many people run acrylic tanks and what is their lifespan and/or failure rate? I find it difficult to gauge this because I've never owned one and across all aquarists there's probably >100 glass tanks in use to every 1 acrylic so the acrylic failure rates probably get mentioned less when they occur.

There's a long time LFS owner near me that has a lot of big acrylic tanks (largest I've seen is 1600 gallons) with monster fish in his store, plus more at his home. He was telling me he would go glass on tanks up to 400-500 gallons if he was never planning to move it again. He and other monster tank owners have suffered tank failures that have made him trust glass more. I found this counterintuitive to popular/common knowledge but very few people exist in the multiple monster tank hobby and he's done this for work and home hobby for a long time.

The only acrylic tanks I've ever seen broken were a result of an accident, like dropping when moving. Glass tanks I have seen many that broke just standing and in operation (usually on an inadequately leveled base/stand).

What size(s) of tanks and what materials were you considering?

For larger and deeper tanks, it's actually best to have small spacing (1~2mm) between panels whether using silicone or PU. Silicone technology has improved with longer warrantied working life, structural grade strengths, modulus (amount of flexibility & compression), colour, different cure mechanisms etc with hybrid silicone and PU being part of this. Sometimes you want flexibility, sometimes you want rigidity - you don't want glass to make actual contact with a structural frame for example.

Also toxicity on the material safety sheets will drop once fully cured.

It's mostly personal preference and experience between glass and acrylic tanks. A typical acrylic fish tank with precision cut edges would be best solvent welded in usual fashion.

Not interested in promoting glass or acrylic as being better but I've got 3 acrylic tanks - 3m x 1m x 1m on very beefy steel stands sitting empty in my fish shed because I'd have to move 100 ish tanks and pull down a shed wall to get them out. I'll probably cut them into pieces instead one day. Acrylic is not my preference but only after trying them out myself.

There are plenty of examples of acrylic tanks failing. This link shows some of the public aquarium failures that made the news.

https://www.plasticstoday.com/materials ... riums-fail

Great little article, thank you for linking. Creep rupture, huh. Untanglement of polymer molecular threads under structural stress. Humankind is so proud of its accomplishments but, a-ah, how suddenly attractive become a mask and a snorkel and natural bodies of clear water, like a flooded stone quarry! This made me uneasy about my own acrylic "creations", which I habitually wing. I only hope and pray they blow up at night, so no humans get hurt except my plump ego.

Just to clarify, in my prior post I was speaking of my modest 1sthand experience dealing with acrylic and glass tanks of the hobbyist sizes.

Some of those public aquarium tanks were over 150mm thick and would have been professionally designed and installed.

I'm sure all tanks can fail. It's just that big tanks may fail spectacularly.

I've had glass tanks fail too. As previous owner of several retail aquarium stores which provided installation services, I've plenty of horror stories. Some quite dangerous/scary.

On a more entertaining note, I was on a ladder working on the top tank of a 3 tier rack of 4 x 2 x2 (120cm x 60cm x 60cm) tanks. I didn't realise that I was leaning on the centre glass cross brace until it suddenly snapped and the glass sides flexed out so the bottom seam gave way dumping all the water into the tank below instantly. The sudden additional weight of water caused the middle tier tank to fail which dumped into the bottom tank which promptly failed too.

This all happened in a second or two and although I was watching this cascading drama, by the time I fully realised, I was ankle deep in water and flapping fish.

That memory also reminds me of a time I watched a large pacu in a 12 foot long 36 inch deep glass tank zoom up to the end to greet me (expecting food?), turn around and zoom back. The water compression wave of this powerful swish literally "popped" the end panel of the tank off. If I wasn't standing right in front watching it, I wouldn't have believed it. Almost three tonne of water poured out the open end in slow motion.

All of my fish rooms have floor drains. I don't lean on glass cross braces anymore.

Great stuff Although you are relatively young still, you need to get started on and publish memoires, Aquaholic! Stories like these would be perfect to break up the chapters of your unfathomably immense (to me) knowledge, experience, and resourcefulness in all aspects of fish keeping. Consider including terabytes of your photography too

I worked in one of the oldest MA stores and it hadn't renovated for since it opened so 30 years, those tanks many were standing till the eventual refit but some had to have various work on I was told just to stand. Some there was also a leak between tanks in a system.
Another store I worked at definitely not as old the silicone went much sooner and someone managed to push through during algae cleaning. Another factor is algae cleaning I noticed as some people are quite careful and algae cleaning silicone can remove bits particularly with blades but seen it with toothbrushes.
Some Loricariids might not help, while I never experienced it with the reported Leporacanthicus and Scobinancistrus, I've seen Peckoltia eat silicone.