Warren

For some reason people think poly fixes up all erros in a stand design. From my previous post you can see the poly has almost no load on it if the stand is properly designed so it will not deform to take up errors. It's important to get the stand correct. Therefore 40mm poly will do nothing more than 10-12mm poly. As previously stated, 50mm minimum composite under the tank if supported as you suggest... Ply would be ok (2 x 25mm marine ply) or 50mm tri-board. The only purpose the poly serves is to take up very small point-loads like a slightly proud screw head or a piece of grit you missed when cleaning the stand or bottom of the tank. Other than insulation and point-loads it serves almost no other purpose.

Thick about for a second - divide the surface area of the tank bottom by the surface area of the stand members and this ends up as the multiplier for force on the poly... A tank of 2400mm x 1200mm = 2880000mm² If the stand has 50mm wide top members spaced at approx 300mm this means 9 members 1100 long + 2 across the front at 2400 long so; 9 x 1100mm x 50mm + 2 x 2400mm x 50mm = 495000mm² + 240000mm² = 735000mm² so the multiplier is 2880000 / 735000 so approximately 4. If the tank weighs 2000kg this equates to 2000/2880000 = 0.6944g/mm² so basically nothing. If there is no bottom support it will be 2000/735000 = 2.72g/mm² so 4 x as much. You would need to see if this loading short-term and long-term will cause the poly to crush so the metal directly contacts the glass. Adding a decent thickness of laminated wood under the tank helps the bottom glass significantly and lowers the loading on the poly.

All front to rear bracing should be 200-250mm wide and along the front and back edges should be 125-150mm. Both should be minimum 10mm thick but 12mm would be a lot better as the width of the silicone connection to the front and rear glass will be 20% wider. The front and rear pieces should also be ground along their length so they are dead-flat. This will allow a very thin silicone joint for added strength due to a more uniform pressure loading.

I went away from all-glass tanks for this very reason some time ago. I'll only go with steel frame tanks with the base integrated into the design. This way the glass is pressing into the silicone at the joints and the water pressure actually helps keep things together. The silicone is no longer a structural component of the aquarium and becomes only a sealant and virtually all the strength comes from the steel and other composite components making up the complete tank. The tank can also be secured to the floor with bolts or put on an isolation platform - whichever is your preference. Having a well braced stand will not stop the tank shaking apart however and the silicone is about as likely to tear as the glass to break in a good shake on a tank this size... When you do build a stand that properly supports the tank (almost no flex) so the bottom glass is evenly supported you will also have built a stand that will resist earthquakes as a side effect...

A tank this size could be over 2000kg. If you use gravel to a depth of 75mm that alone will be around 750kg... 25mm tube is way too small. The strength of the tube is fairly linearly proportional to the thickness of the wall - eg, you double the wall, it's twice as strong. The strength based on tube size is close to a cube law in strength however. If you double the overall width (say 25mm to 50mm) it's close to 8 times stronger. For a tank this size I would use 75mm x 50mm x 3mm RHS as a minimum and it would need to be supported by a vertical leg every 600mm minimum + have appropriate diagonal bracing. Under the tank I would run a front to back member of the same size every 600mm as well (so to line up with the legs). You may also need a row of legs along the middle of the tank (not just front and back). I'd also put diagonals between the front to back members for stabilty and extra support. You will need about 50mm thick board under the tank - something like tri-board. I would simple fix this to the steel frame with no-more-nails. You put the no-more-nails on the steel, sit the single sheet of tri-board on top, place about 12mm poly on top and then sit the empty tank on top of this. This will force the board to conform to the shape of the tank bottom and the glue will act as a filler between the wood and steel as you will never get the steel stand perfectly straight or level. Good luck with anything smaller - come talk to me after and good sized earthquake and then we'll see if this was overboard...

Hi Henward, Most of the articles and calculators found on the internet at present are based on my original article here: http://www.fnzas.org.nz/?p=1732 A lot of them have actually asked for permission to reproduce the arcticle or use the calculator but some have simply plagiarised it an taken the credit for themselves. The two links in your post are both based on my original but only the aquatools has bothered to ask permission to use it. This statement is incorrect. The calculation already assume euro bracing of adequate quality is used so the safety factor calculated is the actual safety factor. In the tank photo shown above the strip of glass running along the front an back edges is too narrow to add significant strength as is at risk of breaking. If there were 2 front to back braces instead of one it would be better. Alternatively, if the strips were twice as wide it would be ok. The glass thickness article states 'all four sides simply supported'. This means all four edges of the glass have support as if it were as very rigid steel frame that does not flex under the load. It is possbile to have no top bracing but you have to modify the alpha and beta constants to cater for this. I've added another Excel file with the ability to calculate the glass thickness for unsupported top edges. There are 3 sheets in the file, siderest, sidefree, bottompanel. Siderest automatically changes the aplha and beta constants as you change the length and width but the other 2 sheets require you to change the values manually - don't forget to do this. siderest - standard tanks with Euro bracing sidefree - Open top tanks with no top bracing at all sottompanel - bottom panel

Although, I find too much vodka makes it more difficult to remove. 8)

Yup, Cyno thrives when phosphase are too high or too low, when Nitrogen is in excess and CO2 is too low relative to the light level. It can only thrive when the balance optimal for plant growth is upset. It can also thrive if there is too much UV vs nutrient balance and CO2. In tanks with no plants cyno says YAY!!!! - Especially when nitrogen is in abundance.

:rolfl:

If it's a bimetal type thermostat it will draw no power when the contacts are open - exactly the same as if it was unplugged. If it's an electronic thermostat then it will draw considerably less power than a stereo in standby while it's monitoring the temperature and not heating. We'd be talking about a few cents a year to pay for it and the power draw will not add more than a few mW of heating to the tank. Actually, lets work it out; Lets say 10mW usage in the electronic thermostat when not heating. so, 1W/0.01W = 100 seconds to use 1J of energy (1W = 1J/s) 1kWhr = 1kJ x 60 seconds x 60 minutes = 3600kJ = 3600000J since it takes 100 seconds to use 1J it takes 3600000 x 100 = 360000000 seconds to use 1kWh of chargeable power. There are approx 31536000 seconds in a year so the cost is 31536000 / 360000000 = 0.0879 x your kWh charge. Mine is about 20c/kWh so the cost of the heater running all year in standby is about 1.75c so basically nothing. Hopefully this is about right...

Should be all go now - you may have to log-off and log-on though.

That will be because to don't have access rights set to get into this area. What club do you belong to and have they paid their capitations and sent us their membership list to update the site users for access?

Anyone can attend. The FNZAS is an incorporated society and its affairs are therefore open to the public. The AGM is restricted to the committee and 2 delegates from each affiliated society but observers are welcome and often get to speak if they want to on matters of discussion, they just can't vote on anything. The AGM is usually only a small part of the event with the bulk of it being social with many different things happening. It's a chance to catch up with old mates and make new ones.

Hi Everyone, The conference 2013 details and registration form are now available on the FNZAS front-end. http://www.fnzas.org.nz/?page_id=3195

Probably not, you just needed to refresh your cookies.

Adrienne, please try logging off, then logging on again (on the main part of the site, not the forum). If this doesn't work you may have to clear your FNZAS cookies. Everything is ok with your account so it should work.

It may be. Since it appears you can't log in I'll reset your password and send it to you by PM.

You may have to log off and log on again...

Try now, you weren't set up...

Ok, try now.

Are you a financial member of the FNZAS or just a website member? Oops - just re-read your post and you are a financial member so I'll check this out If you are a financial member but your details have not been forwarded to Zev then your status will not have been changed to allow viewing of the members pages. We have had some issues with information not being sent to us. In Adrienne's case, her access is correctly set and should be able to view anything in the members area. You do have to log in to gain access though. If you are a financial member, do have the access rights granted, have logged in and still can't access the members area, let me know and I'll try to work out what is going on. I can see it ok but also have the highest level access rights. Worst case I'll set up a test user to check its functionality.

The 'Members' section of the forum is disabled for privacy reasons. The current version of phpBB will show anyone all details of all members even if they are a guest. It's not possible to limit this to registered members only or have controls over what can be seen - it's all or nothing. We've opted for nothing to protect everyone's privacy rather than spam engines trolling for contact details...

Caryl, I was thinking of doing one version with a knob and one version with buttons so it should keep you happy!!

I need to write an article for the next Aquarium World. I think I might just write one on how to DIY your own temperature controller. Unfortunately to do this yourself using electronic bits you will need to know a bit about electronics but at least the info will be there for anyone who wants to give it a go.

It's possible you got very small areas of very local low pH after adding the pH-down that were 1 or 2 points lower than the average. If the fish swam through this it could damage the gills. After a time this will mix in and average out to the pH you measured. If you are going to add products to adjust pH you need to remove several litres of tank water, mix the pH modifying product into this to seriously dilute it then very slowly dribble it back into the tank over about 30 minutes and it must be added to an area of high-flow to force it to be distributed evenly. Dripping the pH-down product directly into the tank will create small areas of concentrated low pH until it has time to properly mix in. As fish are naturally inquisitive they will often swim over near your hand where you are adding the drops - bad news...