Small Tank Specs

Discussion in 'General Discussions and Advice' started by scubaninja, 1 Dec 2008.

  1. scubaninja

    scubaninja

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    Hi hennie
    I'm going to build a small tank to sit beside my main tank as a sump extension for my skimmer(sump space issues). I was thinkin something along the lines of 600(H)X350(W)X400(L). maybe a bit smaller, but thought i would post the largest dimensions i was thinking of using as a smaller tank would then be of lower risk.
    The glass thickness calculator suggests a glass thickness of 6mm, which i think is adequate aswell, and it suggests a bottom glass thickness of 13.9. That is pretty thick, but if i put 6mm in the base section the safety factor goes down to 0.7. I guess i can buy two base panes of 6mm thick and then glue those two together to make twelve, how would i need to go about this or would a 6mm only base still be ok even though the safety factor is 0.7? how prone to a crack or something along those lines would i be?
     
  2. AdS Guest




    to hide all adverts.
  3. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    I must rush, and will answer in more detail at a later stage.

    No, a safety factor of less than 1 is an indication that the glass will break VERY easily, and I would not consider it.

    Your problem is with the 600mm height. Consider that even if the tank is 600 high, your water level will only be around 550 - re do the calcs with that figure.

    Two 6mm panes will not be as strong as one 12mm pane. I would suggest that you try to get a 10mm pane for the bottom - 10mm is not so expensive, and is more readily available.

    Hennie
     
  4. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    thanks hennie, i figured that it was the height being the issue when i was playing around with the figures. will try the 10mm glass
     
  5. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    i also want to get a hole cut in one of the glass panes for an overflow, what would this do to affect the strength of the design?
     
  6. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    i did the calculations with that height because that is the height of the water, i forgot to increase the glass size to account for this but basically that is the water volume. I need to drill a hole in the side of the tank for an overlflow, which pane of glass would be the safest one to drill into? How far below the top of the glass do i have to drill for it to be safe? I will be getting the glass company to drill all the holes so it will be done properly and not by me, and for the trouble of having reduced the strength of the structure, should i just build a small over flow? if that would be the case the overflow would then have to go on the shorter side(ie not the length)

    After taking proper measurements of my needs of the tank it comes to 620(H)X540(L)X380(W).
     
  7. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Even the shorter side (width) of the tank will allow more surface water to overflow than a hole drilled in a pane. I personally have a weir overflow across the one side of my tank, and can vouch that it works very well.

    Even a professionally drilled hole will still result in weakening the glass it is drilled in, so I would recommend that you rather go for the weir-type overflow.

    Hennie
     
    scubaninja likes this.
  8. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    thanks hennie, this is to put my skimmer in as my sump is not tall enough, so surface skimming isn't really a factor, i think. do you have a pick of your overflow?
     
  9. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    hennie, what do you think of perspex? do you think this little tank can be made out of perspex with a decent degree of safety? I've managed to get in contact with a very good fabricator as he is doing my skimmer holes etc, and he says it would be alright. 5mm be alright? to be safe i would put in some euro bracing
     
  10. keyaam

    keyaam

    Joined:
    28 Jul 2008
    Posts:
    2,502
    Likes Received:
    16
    Location:
    Cape Town
    Its gonna cost more. perspex is expensive scuba
     
  11. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    I really don't have any personal experience with Perspex tanks, so I really cannot comment. At a wild guess, I would think that 5mm Perspex will not be sufficient for a 600mm water pressure, even with bracing.

    Perhaps someone else with experience can comment?

    Hennie
     
  12. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    thanks hennie. i saw a tank built out of perspex today when i went to the fabricator. the bonds seemed very strong, but it did flex a little. but it was only three mil perspex. i think that if i brace down the body of the tank too i might get away with it but i was assured it would be ok. i thought it may be nice, if this is all cheaper than glass that is:) so i will let you know:)
     
  13. Shaun

    Shaun Retired Moderator

    Joined:
    29 Aug 2007
    Posts:
    5,274
    Likes Received:
    15
    Location:
    KZN
    Are you sure it was perspex and not acrylic.
     
  14. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    i think they know the difference
     
  15. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Actually, Perspex is just a trade name for acrylic. What's more important is to distinguish between cast (good) and extruded (not so good) acrylic, Perspex makes both types, so be careful...

    Here's a few links:
    Working with Acrylic
    Perspex South Africa

    Hennie
     
  16. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
    Perspex South Africa recommends the following:
    • 600mm deep x 300mm wide - 8mm thickness
    • 600mm deep x 600mm wide - 13mm thickness
    • 600mm deep x 900mm to 1800mm wide - 16mm thickness
    Hope this helps...

    Hennie
     
  17. Shaun

    Shaun Retired Moderator

    Joined:
    29 Aug 2007
    Posts:
    5,274
    Likes Received:
    15
    Location:
    KZN
    Their is a big price dif between the 2. Maizey Plastics called them perspex and then acrylic. They are similar and look the same, but their is a big difference between the 2 what ever it is called.
     
  18. scubaninja

    scubaninja Thread Starter

    Joined:
    20 Jul 2008
    Posts:
    6,739
    Likes Received:
    21
    Location:
    Durban
    well i hoped they would know the difference cause i don't. but after finding out the prices i'm just goin to go with the glass:) will look nicer i think when i put black silicon on it:)
     
  19. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,769
    Likes Received:
    582
    Location:
    Sandton
    on a side note, where can i find these "calculators"? and anyone got a pic of euro-bracing?
     
  20. Reef Maniac

    Reef Maniac MASA Contributor

    Joined:
    15 May 2007
    Posts:
    2,899
    Likes Received:
    112
    Location:
    Bloemfontein
  21. dallasg

    dallasg Moderator MASA Contributor

    Joined:
    14 Dec 2008
    Posts:
    16,769
    Likes Received:
    582
    Location:
    Sandton
    thanks
     
Recent Posts

Loading...
Similar Threads - Small Tank Specs Forum Date
[wtd] Small running tank Wanted 22 Sep 2016
existing tank with gha to smaller frag tank Beginner Discussions 6 Sep 2016
[wtd] small tank wanted Wanted 13 Jan 2016
Small Grey Star Fish in Tank General Discussions and Advice 2 Nov 2015
small reef tank New Members 25 Aug 2015
[wtd] looking for small nano tank-boyu ideally Wanted 10 Jan 2015
Comp: How I cured my too small tank syndrome Competitions 3 Nov 2014