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FAQs about Commercially Made Tanks, Sumps Made of Acrylic

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http://tenecor.com/ <Gone>


Acrylic Tank Rout Top Edge        11/14/19
Have a 380 all ¾ inch acrylic tank I am setting up. It is new, I am not so happy with the edge the tank builder left on the front and sides, I would like to finish it off by using a router and a quarter round bit, giving a nice sleek rounded edge to the top edge, I have seen tanks with the sides like this but not the top, I cant believe the stress on the joint would change or be any different as its not modifying the joint, particularly since I would think the top seems should have less stress that the sides. Just wanted to get a second opinion
<I see no problem unless, that edge was left intentionally to give strength to the tank, sometimes a slit is made on the top and bottom panels to insert vertical sheets (particularly in taller tanks), if so, a part of this edge should be left to ensure structural integrity. If the vertical panels are just glued to the floor and top without the mentioned slit, you may reduce the remaining edge with the router; If you could send us a photo, it would be great, just to be sure how the tank is built and if this is a standard or show tank.>
Thanks for all you do
<Welcome. Wil.>

Acrylic tank lifespan     3/30/17
Hi, I am rather humbled to ask, but what is the "lifespan" of acrylic aquariums for both larger and smaller models? I ask because I have been in the tank maintenance business for 25+ years, and some of my clients tanks are that old or older.
<A well-made system of small/er size (hundred gallons or so) should last twenty years or more if kept on a level, planar stand>
Also, if an acrylic tank starts to get the "cloudy spots" in the seams, or any other tiny leak, will those seam leaks grow?
<They will unfortunately. IF there are whited out areas that approach half the seam width, a good idea to drain, have corner doweling solvented in all inside seams>
Thank you in advance
Bill Thomas
<Welcome. Bob Fenner>

some pond planning questions     2/22/14
Hello WWM Crew!  Although it doesn't quite look it out the window, spring is coming!
 I'm reading, learning and planning for it!!!!!  I'm looking for a reasonable custom acrylic maker to design an indoor rectangular shaped (with rounded corners for Pearlscale goldfish) pond for me, 10'L x 5'W x 4'D
<... this construct is going to cost at least several thousand dollars... perhaps a couple of tens of thousands>

 (any referrals for the Poconos region of PA
<Oh! Am sending your note to Michelle Lemech; who lives in the area>
or thereabouts would be appreciated!!!!) with custom stand (of course!) that I'd like slope bottomed to a bottom drain to gravity feed an EazyPod filter from Evolution Aqua.
From what I gather, it is customary to turn over the pond volume 1-2 times an hour; the pond will be +/- 1500 gallons (5674 liters)  so will the turnover rate be 1500 gallons an hour?
<I'd make it at least twice this>
  Do I need to size the pump after the EazyPod for this rate, or will I need to size it differently to  accommodate the protein skimmer as well?
<... hard to adjust skimmers on freshwater systems to work>
---it requires 3000 liters per hour (793 gallons per hour) plus the height to get to the top of the unit at the top of the pond?  How do I size the pump for the two units, or do I need two separate pumps? back to back?
<Better to use separate pumps for sure>
 Similar questions appear for the piping dimensions, what are they based on?
<Lengths of runs, turns, induced drag. A more/less safe guess is to use the  diameter of the lines on the discharge sides of your pumps... If they're (likely) 1.5 or 2 inch... this is what size plumbing I'd use>
  The examples on EAs website show the MAX rates for the EazyPod-10,000 l p/hr (2,642 gallons p/hr) and the rate shown on
Clarity's website is for the MAX rate of 3,000 l p/hr (793 gallons p/hr) with 40mm tubing dimensions.  EAs example drawings show a 4" bottom drain to 4" piping.
<This can (and should be) reduced down to 2"... no need for larger>
 If my tank is smaller, for fancy goldfish are smaller than their Koi cousins, but just as messy and as such require overkill filtration,
should it run at the rates/sizes for the actual size of the pond or at the maximum rate of each appliance?
<For the pond>
 How do I size the bottom drain (4" or 2")
pumps and tubing (4" or 2")?
<40 mm... 1.5">
I'd like to send the return water from the EazyPod to a Clarity CL3 foam fractionator and two water returns to help circulate the water (I believe the CL3 needs 1.5" tubing, that leaves 2.5" available to split into two 1.25" TPRs)  I am going to hold off U.V. for now, I want to move into our retirement home first (closing next week!!) and get an idea of how much natural light there is to affect the pond before I decide if U.V. lighting is needed or not. 
Where do valves/unions/ball joints, etc. go?
<See, read on WWM re:
  and please explain the use of each type (very confusing), and when to use which one.  EAs site recommends installing "an isolating valve (3" or 4") (90-115mm) slide or ball valve on your inlet gravity line before the EazyPod."  So if that needs an
additional one prior to the unit, does the skimmer need one before it too?
 And of course, which type/size?
Okay, to summarize, HELP! with the sizing of bottom drain (4" or 2"), pipes/tubing (4" or 2"), external pumps to get a 1500 gal. sloped bottom pond thru the bottom drain, to the EazyPod With Air filter, to the Clarity CL3 foam fractionator and into the pond.  Being a beginner is brutal---thanks for any guidance you can give me!!!!! 
Lisa     Also, do you rec. buying a bottom drain that is aerated?  Did I miss anything important to filter this pond?  Thank you so much yet again for so freely sharing hard to come by advice!!!
<I encourage you to read a bit more re your options... reducing the length to 8', the height to two or so feet will save you a great deal of money on this project. Bob Fenner>

Acrylic Tank      2/10/14
I have had a salt water tank for more than 25 years. Originally a FO tank and more recently a reef set-up. The tank I have always used was a 45 gallon, tall tank and thus my oxygen levels were usually low. Seemingly, I never had any problems but I would like to bring my oxygen levels up. I am considering changing to a conventional 55 gallon tank. With that said, I was thinking about an acrylic tank (lighter, better clarity...etc.) but from what I can find, all acrylic tanks have partial tops molded in.
<Yes; part of their structural strength, to resist bowing>
I used to have the top of my glass tank completely open (except for where the cf ho lights sat) for the oxygen transfer and am worried that the semi-closed top will impede the oxygen transfer at the surface. I have good turnover/agitation in the tank (pumps).
<Can, might. Good to introduce/mix atmosphere elsewhere generally... as in a sump, skimmer>
2 questions;
Are there any acrylic tanks similar to glass where the top is completely open? I assume this is done for strength so there may not be.
<These can be fashioned, of much thicker (and costlier) material; but none are stock as far as I'm aware>
Is this a valid concern?
<Not really. A bit more difficult to work in the system, get large décor (e.g. rock) in/out, and need to be aware of where high heat lamps (for lighting) may be too close to>
Any assistance is appreciated.
J.T. Craddock
<Hope this helps. Bob Fenner>
re: Acrylic Tank      2/10/14
Thanks for the prompt response.
<Certainly welcome. BobF>

Brand new acrylic aquarium with "floating" bottom    1/27/14
I hope you can reply to this question today.
<I as well>
Long story short, I just received a 500 gallon 90" x 36" x 36" 1"-thick acrylic tank and steel stand custom fabricated by a supposedly well known and highly regarded fabricator.
<You, we are free to name names>
 Problem is a good portion of the tank bottom floats over the stand base.
<Floats... as in doesn't touch the base all the way around? Even when filled?>
 After much investigating and looking, it turns out the tank is about 3/16" shorter in height measured in the middle front of the tank than the ends. 
<... 3/16"...!?>
Each end is 36" exactly.  The middle is about 35-13/16".  This causes the tank bottom to flex up and top to flex down.  This in turn makes a majority of the front half of the tank float. 
<Can you define, describe this in a different way?>
The back and right end appear to be firmly supported by the stand.  The left end is about half supported.
<... have you checked the stand itself... to insure that IT ITSELF is level, planar?>
 The front mostly floats a 1/16" or so.  The steel stand came with a 3/4" plywood top adhered to the steel stand.  I placed a 1/2" sheet of the heavy duty expanded Styrofoam sheet used under concrete slabs between it and the tank.
<Ah, good>
The fabricator says this irregularity is likely due to thickness variance in the top and or bottom acrylic sheets.
<What? No... assuredly not>
 He says all cutting is done on CNC machine, so the side sheets are absolutely exact in dimension. (I'm not with the tank right now to confirm this.)  I did research and see that cast acrylic sheets (which this is) have thickness tolerance variations of up to 15%. 
<15%!... cast? How thick is this material? Do you know the manufacturer? Is this an import (from Mexico? China?)>
So this could explain my problem if the center of the top and bottom panels are thinner the ends...essentially making the front of the tank an hourglass shape (though only by fractions of an inch).
<VERY small fraction>
The fabricator says this is not uncommon and this can be addressed by shimming between tank and stand to get full support under the tank.
<... shim UNDER the PLYWOOD... NOT the tank>
 I expressed my concern that this would just address the perimeter and not the center of the tank.  He said they could reset the plywood top and shim between the steel stand and the plywood and get full support under the full perimeter and at each of the three additional cross braces that run along the top of the stand front-to-back.
<Yes; this can be done... easily>
 Again he says this is common to make these field adjustments and that the tank is not flawed in any way.
<... I'd be measuring all... again>
My question to you is this.  Are all these assertions made by the fabricator correct?
<Not all; no>
  Is it acceptable to shim this 500 gallon tank as he proposes.
  Is this common/acceptable practice (shimming)? 
<... well... not generally necessary w/ all-acrylic tanks>
Would the shims hold up over the life of the tank (which is hopefully decades)?
<Yes... IF made up of solid material, not allowed to get wet, decompose or rust>
 I spent thousands on this tank.  I don't want to be unreasonable, but I want it to be "right" and obviously don't want a catastrophic failure to occur at some point in the future because of this.
<Oh; as a former fabricator, installer of many large systems I can definitely relate, commiserate. All should be well here IF the ply/stand is adequately shimmed>
<Welcome. Bob Fenner>

Q & A about acrylic    11/19/13
Thought this was interesting Bob, might want to share it.
<Ah yes; will do. B>

Acrylic Tank Sitting In Garage For A Year – Still Good? – 12/02/12
<<Hey Laura>>
We bought a used 240 gallon acrylic aquarium from our LFS a while back. It is 8 feet long and due to some logistical problems and an inconvenient spinal surgery we haven't been able to move it into our house. The tank has been sitting out in our garage for about a year now. We live in Chicago, so the winters get cold and the summers are hot. We are trying to figure out if the tank will be ok if we bring it in and set it up or if the weather fluctuations would have made it too unstable...leaky, warped etc.
<<If the tank was sound when you purchased it, and hasn’t been damaged during transport/handling, it is likely still fine…but there’s a way to tell…fill it in the garage and observe it for a day or two>>
Do you think it is worth a shot or should we just go to plan B? (If it matters, we live in a condo and don't have a hose that can reach the garage to test the tank prior to bringing it in).
<<Mmm…nothing beats doing a fill test before bringing a used tank in to the home.  Odds are the tank is fine, but…  It’s your call>>
<<Happy to share…  EricR>>

450 Gallon Clarity Plus Acrylic Tank (needs a ‘test’ fill) – 02/28/12
<<Hey Ken>>
I just purchased a 96x30x36 acrylic tank.
<<Nice…I have a 96x30x30 myself>>
It's approximately 20 years old. There are very few scratches, and there appears to be minimal crazing.
<<Very good>>
The tank is 36in high, 34in to overflow.  It is only 3/4in thick is this under built for 36in high tank?
<<Likely so>>
I was thinking of only filling water 30in to reduce pressure?
<<This may or may not work; it depends much on the “support web” of acrylic that makes up the top of the tank.  My tank is also of ¾” acrylic and was made by Tenecor in 2003.  I have no bowing with a 30” water height, but the tank also has a very substantial support web/brace of ¾” material at the top.  The tank has not had water in it for nine years is this an issue?
<<Hard to say…will depend I think on how it was stored.  At the least, I think you should find a place “outside” to fill the tank and let it set for a few days or so, to see what transpires>>
Should I reinforce corners and brace top?
<<Always an option…is up to you>>
It has black acrylic back with bubbles but none to speak of in clear section. Might have happened during manufacturing?
I was told that tank has bow in front when full, that's why I was considering only filling 30in.
<<I would test this for myself and then determine what needs to be done.  The bowing may be minimal/something you can live with…or easily rectified or diminished with some simple repairs as you described.  But right now you/we are only making assumptions>>
I am getting conflicting advice from manufacturers. Please advise.
<<Set the tank in a safe location and fill it up for a test run...we can then discuss it further if you wish>>
Thank you, Ken
<<Happy to share…  EricR>>

Thanks for the feed back. Top cross brace is 1/2 in thick. It has two cut outs with aprox 5in wide brace.
<... I take it there is more than one of these>
Was thinking of framing top with oak and tying in back and front for extra support. Good idea?
<Mmm... not really... the acrylic itself should be strong enough... for looks though... I find the near surface air/water interface to be too bright from reflected light>
Is 34 in to high for 3/4 in thick acrylic?
<Not too high>
  What size triangles do you recommend? And where can I purchase?
<What "triangles"? Some sort of square acrylic stock for solventing in internal seams? Large/r acrylic shops, fabricators have>
  Along w/welding solvent.
<And this... see your local directories... Yellow Pages and such>
Would you recommend filling w/Luke
warm room temp water or cold?
Thank you very much for your valuable advice.
Can't fill outside 10 degrees :)
<Please proof your writing before sending... Bob Fenner>

180 Gallon Half Cylinder Tank. Used acrylic; size, shape, structural integrity    2/22/12
Hello everyone!  I've been coming to this site for years for tips and advice
from other articles, but this is my first time asking a question.  Well, I just picked up a 180 gallon half cylinder acrylic tank (60x30x30 with 1/2" acrylic).  All the seams and joints look good (no white frost), has some minor crazing, and I have the typical scratches which I am about to attack with the help of the Novus products.  My question is, how structurally sound is a half cylinder acrylic aquarium of that size? 
<Fine, sound as long as placed on a strong, level, planar surface/stand... check before, during and after filled>
Is there any advantages
or disadvantages for a half cylinder design;
<Just looks really>
should I be concerned about more pressure on the seams due to the design?
<Not really; no>
  I have no doubt that this is a solid tank, I'm just wondering about the longevity of this tank considering the proper care, leveling, and stand/support of this monstrosity.
<Should last for decades. Bob Fenner>
Re: 180 Gallon Half Cylinder Tank
Bob, thanks for the quick reply.  Couple more questions, is 1/2" acrylic sufficient for a tank this size (60x30x30 half cylinder)? 
<Yes... thicker would be better, but more expensive>
What kind of bowing should I expect (if any) on this tank?
<About a 1/4" near the front middle max.. Shouldn't deform so badly as to affect transparency appreciably>
 Thanks again for your assistance.
<Welcome. BobF>

Tenecor - still in business? 10/13/10
Hello WWM Crew,
I have a question maybe you can help me with. I work for a small aquarium maintenance company, and we have 5 orders placed with Tenecor, which are now 8-9 weeks out from date of order. They were supposed to be 4-6 weeks!
<Hmm, unusual>
I have tried unsuccessfully to contact Tenecor over the past 2 weeks, via phone, e-mail, even fax. I am beginning to wonder if this company has gone under.... have you heard anything?
<I have not, but just called, left a msg...>
Any whisperings you have heard would be greatly appreciated.
Bob Fenner>

Re: Young smooth hound shark question, sys., acrylic tk. sel.   – 06/12/09
Hi gents - just wanted to give you a piece of advice/suggestion for other aquarists interested in keeping sharks/large tanks.
<Please do>
I work for a company that often deals with large volumes of chemicals - some safe, some very unsafe - and we have catch basins under all the machinery in the event of a spill - these tubs go up to 10K gallons. On a whim, I emailed our contact there, and asked him for a quote on a clear acrylic hexagon tank
- 16' diameter, 6' deep (roughly 7500 gallons). Take a guess at how much, and the lead time? You'd be wrong. $12,500 delivered. 7 days. And a 3 year warranty against ANY leaking
<Mmmm, I'd have you do a bit more look/seeing here. There are "quality differences" in the acrylic material being used... Some are far more appropriate for aquarium use than others... This "tank" may not be/stay
very clear>
The company in question asked not to be named, as this isn't their bread-and-butter,
<? Makes me feel dubious re the use of their products... is this simply a liability issue?>
but they told me that any chemical safety company ought to be able to do the work in the cost ballpark. For
comparison, I got quotes from 4 reputable aquarium builders for the exact same spec tank - the lowest quote was $32K, and the highest was $71K.
<Seems about in the range...>
Thanks again for your great site, and great advise. The sharks are doing great still, eating krill every 2-3 days.
<Keep studying... RMF>

What would you do? Choosing a tank, acrylic manuf. 11/21/08
After searching many LFS and doing much research on www etc, I have decided that my 180-gallon 72x24x24 upgrade will be an acrylic tank since I live in California.
<A good decision.>
I have my choices narrowed down to two acrylic tanks and I cannot decide.
Please tell me if you would go with choice 1 or 2.
1. CASCO/SeaClear with 3/8" acrylic on the sides and 1/2" on top and bottom.
2.Clear For Life 1/2" acrylic all the way around for $82 more than the Casco.
<Both quality tanks, but worth the extra cash for the thicker tank IMO. In the long run the tank is small in terms of overall cost, the thicker tank will have a higher resale too.>
I would really appreciate your opinion. One more question, I plan on getting 2-overflows, not in the corners but offset on the back wall.
Should I have the return pipe come through the overflow for nice clean plumbing and look. Or is it much better to not have the return pipe coming out of the overflow, and put it far away from the overflow.
<You can certainly have it come back up inside the overflow, come over the top of the box with LocLine. This will allow you to easily direct the flow about the tank. Do also inquire about throughput sizes on the overflow.
Now is the time to make sure you have enough not only to handle your planned sump flow, but allow for redundancy.>
Thank You!
<Welcome, Scott V.>

On the road to a museuum, Poor English self-promotion re acrylic manuf.  – 09/15/08
yes!, i have built a road to send all cast acrylic aquaria to the museumm.
You dont believe me?. There is a record of our e- mails from some time
ago.I am a custom caster of Methyl Methacrylate Monomer.You dont know
what that is?. Let me tell you, that means i cast acrylic plastic to
size shape and any, repeat any form.Guess what?. I am making a mold to
make seamless and cementless round aquaria.Ninty five percent
finished.Thirty six inches od, Actually i can make any size or shape,i
have over forty years experience casting mma,[Methyl Methacrylate
Monomer],my skills are the highest in the industry,I am the guy who
went to China to teach them to make very thick cast acrylic sheet.
Dupont recomended me. I was a consultant to the largest plastic firms
in the world, including Reynolds Polymer.I find people like to play me
down so the guy making the inquiry wont hire me, so he wont get what i
taught them,[inquired firm] in the first place.I developed a process
to make the finest [defect free] large diameter cast acrylic rods for
the furniture industry in the world.
The large diameter cast acrylic tube with the skinney bottom cemented
on belonges in a museuum,i have the mold,the industry is about to
change.The wall thickness will be increased [really] and the bottom
will be much thicker, all of course depending on the size of the
unit.One seamless and cementless piece.All in one piece.Never leak,
never fall apart.Which would anybody buy?
I am one of one on the web, www.angelfire.com/pro2/frisky
I am talking about ods of 36 48 65 72 80 inches.I work as a consultant
as well.
Any questions??.Please see my website, there is more to me then this.
912 462 7212 I would love to have Bob Fenners e- mail address.
<Best to write me here Robert. My pers. email (fennerrobert@hotmail.com) has troubles at times. BobF>
Thanks for your time,
ROBERT WIENER 912 462 7212
PS- I will put a very heavy guarantee, better then any other, on this
unit.How about twenty five years?.The price will be less then units of
comparable size.

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