Tank Light Keeps Turning On And Off?

The light in my tank has started to turn itself on and off it's an old light about 8 years old and when it first turned off today I assumed the bulb had just gone but a few minutes later it turned itself back on again it did this about 2-3 times, I then turned it off and checked the plug was in properly and switched it back on again it repeated the same thing so when it went off again I then turned it off and attempted to turn it on but it didn't light then I waited a few minutes and it worked, would a bulb do this if they are about to fail? I always though they just go off and that's it or could there be some other problem? the light unit is old so may have some water ingress perhaps, would this cause those symptoms? if it's any help the bulb is a 24" fluorescent plant growth lamp from Arcadia and I do have a spare if need be.

The last bulb i had did this, flicked on and off for a while, but eventually it just stopped alltogether, replaced the bulb and now everthing is fine. Does the canopy have two bulbs in? to check if its the canopy try another bulb

Hi, thanks for the reply, it only has the one bulb I guess it must just be on it's way out I'll replace it and see what happens

betta fish said:

Hi, thanks for the reply, it only has the one bulb I guess it must just be on it's way out I'll replace it and see what happens

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First off its a lamp not a bulb thats what you grow in the garden it could either be the lamp the started or the ballast (gear) try the lamp first if not the next cheapest thing to replace is the starter

walkers101 said:

betta fish said:

Hi, thanks for the reply, it only has the one bulb I guess it must just be on it's way out I'll replace it and see what happens

Click to expand...

First off its a lamp not a bulb thats what you grow in the garden it could either be the lamp the started or the ballast (gear) try the lamp first if not the next cheapest thing to replace is the starter

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Just have a look at the ends of the lamp. If their turning black or discoloured then then on their last legs and should be replaced.

helterskelter said:

walkers101 said:

betta fish said:

Hi, thanks for the reply, it only has the one bulb I guess it must just be on it's way out I'll replace it and see what happens

Click to expand...

First off its a lamp not a bulb thats what you grow in the garden it could either be the lamp the started or the ballast (gear) try the lamp first if not the next cheapest thing to replace is the starter

Click to expand...

Just have a look at the ends of the lamp. If their turning black or discoloured then then on their last legs and should be replaced.

Click to expand...

The ends have a purplish hue to them so yep it looks like it's on it's way out, I'll change it, thanks for all the replies

Replace the lamp and expect things to start working for you. If you have an older fixture, it may well have a starter in the fixture that can be replaced for under a dollar. I bought a twin pack of them and used both in different fixtures but only spent about $1.50 for the twin pack. By the time a typical fluorescent is on its last legs, the starter needs to be replaced too.

I am trying to replace the lamp and have unscrewed the end caps but they don't appear to move very far and the lamp isn't budging I don't want to apply to much pressure incase I break it is there a knack to changing these? if it's any help the replacement lamp has prongs at the end.

betta fish said:

I am trying to replace the lamp and have unscrewed the end caps but they don't appear to move very far and the lamp isn't budging I don't want to apply to much pressure incase I break it is there a knack to changing these? if it's any help the replacement lamp has prongs at the end.
View attachment 60778
View attachment 60779

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Unscrew the end cap then pull the lamp towards your self, the ends are fixed and do not move.
Look at the first pic, you can see 2 holes on the cap, this is where the pins slide out once unscrewed.

Hi, many thanks I managed to replace the bulb and the new bulb was fine for a few minutes and then turned itself off! so I have just purchased a new starter hopefully all should be well though I did notice one of the old lamp ends had a bit of rust on the prongs and within the fitting as if water had got in

walkers101 said:

First off its a lamp not a bulb thats what you grow in the garden it could either be the lamp the started or the ballast (gear) try the lamp first if not the next cheapest thing to replace is the starter

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Wrong, its a flourescent tube, a lamp is complete unit or fixture , bettafish is pretty close with bulb, essentially the same thing give or take the shame and the mixture of gases etc

Everyone knew what was being asked, so why correct something that didnt need correcting? now go to the back of classes and write 100 times 'I will not point of things that are incorrect without checking them first'.



Anyway, back on topic...

I had the same issue and it turned out to be the tube itself and not the unit.

if the seal has broken though around the screw caps its time for a new unit too

§tudz said:

walkers101 said:

First off its a lamp not a bulb thats what you grow in the garden it could either be the lamp the started or the ballast (gear) try the lamp first if not the next cheapest thing to replace is the starter

Click to expand...

Wrong, its a flourescent tube, a lamp is complete unit or fixture , bettafish is pretty close with bulb, essentially the same thing give or take the shame and the mixture of gases etc

Everyone knew what was being asked, so why correct something that didnt need correcting? now go to the back of classes and write 100 times 'I will not point of things that are incorrect without checking them first'.



Anyway, back on topic...

I had the same issue and it turned out to be the tube itself and not the unit.

if the seal has broken though around the screw caps its time for a new unit too

Click to expand...

thanks I don't think the seal has broken around the screw caps I will double check though I do know that the unit is no longer firmly attached to the hood as the screws have corroded and broken so it's kind of just sitting on the edges not attached, there is often a lot of condensation on the lid too which ends up on the light perhaps a condensation tray will help?

If I hadnt seen the images above, I would be sure you are looking at my tank which has this issue.
I condensation tray is always good, as long as you keep it clean, as they can get all green and dirty and tint your light, and it makes it a #28### to fee the fish