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Acrylic tank question


bubbarockies

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That's something called crazing - and it's fairly common in acrylic tanks. I know this because I had to do a ton of research after my brand new 240 started crazing on all the seems within a month. That was bad.

 

This doesn't seem that bad - and it's a weird spot to see it. Usually you get crazing from things moving under pressure - so the seems.  I don't know what forces would be pulling just that section. Are the seems all OK? Do you see any crazing around any joints?

 

Generally speaking - most people think minimal crazing is nothing to be OVERLY worried about, but it means that something is being affected by the water pressure, which can't be good forever. Have you filled it before? How bad is the bow? Mine was bowing over 1/4"....crazy stuff.

 

I drained that one and moved on.

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This is on a non-stress area so my guess is that it is likely from heat exposure from the metal halides that were running on it as there was some significant heat build-up inside the canopy despite the fans.  This area (top center) was closest to the lamps and didn't have the advantage of a localized heat sink (i.e. water).  As Bevo5 notes, this is more common at seams or other pressure spots typically.  You can also see it if you happen to expose the acrylic to certain alcohols so not always a stress/flex reaction - which is why I would be suspicious of localized heat in this case. Doubt it will be an issue with your light setup and I wouldn't expect it to worsen.  Just my thoughts...

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Couple of additional thoughts.  Another potential contributor to that bit of crazing (in addition to the heat) would be some stray UV. Although the MH fixtures used single ended bulbs - which have their own UV protective enclosure - it is still possible that there was a bit of leakage due to an imperfection that could have contributed.  The bottom of the fixtures were basically only 6 inches off the top of the tank at that spot.  Regardless, I wouldn't be concerned about this as a structural problem or an ongoing issue since you are using LEDs (if I recall correctly).

 

If you want to be extra careful (not a bad thing at all) you could get some of the thickened acrylic cement (TAP has it) and run a bead along all the internal seams before filling it up. Since this basically "re-welds" the plastic you have to be careful not to let it run/drip onto the visual surfaces (hence the thickened version).  It is quick and easy to do and gives you some peace of mind. I just had a small acrylic tank I was using for a fuge spring a seam leak and had to drain and reseal it. I have some left over if you want to try it but might be easier to find it near you at a Lowes, Home Depot or something.

 

Hope this helps.

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I'll double check tonight but I think it's mostly isolated to the top.

I'm considering adding some t5s to supplement the LEDs.

 

Sent from my SM-G900V using Tapatalk

 

I don't think that would be anything to worry about as you wouldn't have either the heat or the UV potential even with the T5s.  Let me know if you want to try some of the thickened cement.

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You might as well reseal it along that seam while the tanks is empty - easy to get to. It isn't a high pressure or wet seam like the verticals but might as well play it safe. Just make sure you have the tank setting in a way that will minimize the chances of dripping down the surface and maybe even mask that off just to be sure. Also make sure to get the thickened cement.

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You might as well reseal it along that seam while the tanks is empty - easy to get to. It isn't a high pressure or wet seam like the verticals but might as well play it safe. Just make sure you have the tank setting in a way that will minimize the chances of dripping down the surface and maybe even mask that off just to be sure. Also make sure to get the thickened cement.

Sounds like a plan!

 

Sent from my SM-G900V using Tapatalk

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