# Having a lid cut, what's the best option ?



## stu_ (9 Sep 2014)

Hi
i'm looking to have a glass lid cut to fit over my open top tank, 5mm glass thickness.
What's the best option, cut to sit ontop of the sides, or narrower & use clips to hold in place?
Is one option better than the other, or does it just come down to asthetics?
It's mainly to cut down on evaporation in the winter months, as the room gets a couple of degs colder than the water temp.

Thanks


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## James D (9 Sep 2014)

If you can get hold of the ADA style clips I'd do it smaller personally. I'd prefer to use acrylic though because it can be more easily cut to accomodate for pipe work etc.


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## Trevor Pleco (9 Sep 2014)

I understand light travels better though plexiglass than glass and it's lighter and easier to work with, as James suggests. I've used just 3mm and it works fine, but it depends on the size of tank. You also need some vent spaces or gaps otherwise a perfectly cut piece of glass or plexiglass quickly condenses up...

My situation works quite well as the heat from the T5s a few inches above stops the condensation during the day if I decide or forget to leave the covers on.


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## Tim Harrison (9 Sep 2014)

What sort of thickness works best?...I've used 3mm in the past and it bowed significantly to below the water surface


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## James O (9 Sep 2014)

3-5mm Perspex shouldn't bend, has good light transmission and is lighter than glass


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## James D (9 Sep 2014)

Depends on the size of the tank, I'd use 5mm at least.


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## stu_ (9 Sep 2014)

Thanks for the replies chaps
The tank footprint is 600mm x 410mm & the T8 luminaire is about 100mm above top of tank.


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## Trevor Pleco (9 Sep 2014)

I have two equal size 3mm pieces on a large 1800mm tank, so about 900 by 600 each, bending is minimum and it's nice and light weight. It was a compromise choice as I wanted something thin to allow as much light as possible to pass through it as I sometimes leave for work and don't have time to take the covers off.  There were two grades of plexiglass available over the counter so mine is evidently the stronger and does not break easily if dropped I'm told. I also have 3mm plexiglass on my ATI unit which comes standard, this bends badly mainly because of the heat and is annoying as it can easily slip out of the aluminium channel, so it must be a different grade or something ? I recently needed some more covers for another large tank, but could not remember if I had 3mm or 4mm so ordered the thicker, I was surprised how much thicker it was compared to the 3mm and this certainly dos not bend. It slides in plastic channels/tracks on this tank and I much prefer it to the previous glass I had.  I would suggest 5mm is over the top especially for a 600 tank.

In the first tank described the plexiglass sits on top of the sides, it might not look as neat but is easy to handle and take off.


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## James D (10 Sep 2014)

It's obviously true as you can see it with your own eyes but I'm surprised at that Trevor, maybe your 900 x 600 sheets are something other than acrylic? I still would still recommend at least 5mm.


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## clonitza (10 Sep 2014)

3mm acrylic is more than enough, have one on my tank atm, cheap and easy to cut at home, glass lids make me nervous


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## stu_ (10 Sep 2014)

Thanks all.
looks like i'll have a go at cutting some acrylic at the weekend.
Guess i can make the decision about whether to sit it on top,or use clips, when i've got it.....


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## Trevor Pleco (10 Sep 2014)

James D said:


> It's obviously true as you can see it with your own eyes but I'm surprised at that Trevor, maybe your 900 x 600 sheets are something other than acrylic? I still would still recommend at least 5mm.


James, it does bed a little sure, but these are big pieces compared to Stu's tank, I just turn it over and it straightens itself, I feel 3mm or max 4mm would be 100s for Stu's tank, 5mm is damn chunky imo..


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## Lindy (13 Sep 2014)

I had 8mm cut for my 60x30cm tank but it must have been poor grade or something because is bowed terribly and because there were cut outs for pipes and stuff I couldn't just turn it over. I have the ada glass clips and I find them a bit annoying as they are easily knocked into the tank or down the back during maintenance. They also provide only a very small lip for the glass to sit on. My favorites are the clear plastic ones I got with the dennerle tanks so I'd try to find some plastic ones on ebay. I'm sure I've seen some on there.


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## stu_ (13 Sep 2014)

Like these 
http://www.ebay.co.uk/itm/231067900210?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT


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## OllieNZ (14 Sep 2014)

I liked the plastic ones but no one does them for 10mm glass, so looked at the ada ones and decided I didn't like the price but the idea was sound so I diyed 


Lindy have you tried pinching your ada ones a touch to make them grip the tank better?


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## Andy D (14 Sep 2014)

I use these 10mm clips for my tanks - http://www.ebay.co.uk/itm/171188492104 

I had some 4mm Polycarbonate cut to fit my 600mm x 300mm and it does bow in the middle. Another set of clips in the middle would sort this out though.


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## stu_ (14 Sep 2014)

Just realised,nobody has given an opinion on whether just to sit it on top of tank.
Does it look naff?


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## James O (14 Sep 2014)

If it's a perfect match for the top of the tank it's not too bad.

However you'll be knocking it in all the time so I'd make up some clips, cut the sheet to sit inside and the drill a hole so you lift it with a finger


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## Andy Thurston (14 Sep 2014)

Possible condensation running down the outside of tank if its on top


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## James O (14 Sep 2014)

but with the built in sag it just drops into the tank again


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## Andy D (14 Sep 2014)

I would be concerned with it dripping down the side if it covered the rim completely and wouldn't it be a problem with gas exchange?


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## James O (14 Sep 2014)

Drill a hole or two.  With adequate surface movement you should be good to go

Having said that, a small gap around the edge (internal lid on clips) will be more than enough


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## stu_ (14 Sep 2014)

There'll be a gap at the side where the Lily pipe sits.
It's low tech atm.
Will use clips and thick acrylic.
Thanks for all the info everyone


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## Trevor Pleco (14 Sep 2014)

I gave an opinion on a previous post


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## stu_ (14 Sep 2014)

Trevor Pleco said:


> I gave an opinion on a previous post


So you did Trevor,and I thank you for it.
I lost sight of it,amongst all the talk of 3,4,5 mm, will or won't bow.


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## Trevor Pleco (15 Sep 2014)

to confuse you further I have an old 5mm perspex lid which is bending quit a bit. I also have glass with your clips on another small 25cm planted tank and that's a bit of a fiddle and pain to get off each time I want to do do something in the tank, whatever the case keep a reasonable gap at the back for reducing condensation, piping and to feed.


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