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Discussion Starter · #1 ·
I'm hoping someone out there can tell me why one of my endcaps "flashed" - the plastic/rubber partially melted to the end of the T8 bulb and scorched the inside of my wooden tank hood a few months ago; and then another end cap started to burn/melt today - I suddenly smelled burning plastic/rubber and noticed it was coming from the hood - and then pulled the power. The heat was high enough on that endcap to partially melt it, burn a hole through the side and fuse it to the end of the bulb.

I suspect that the culprit is either 1) age - that either the endcaps needs to be replaced after many years use or the ballasts need to be replaced OR 2) the ballasts not being able to handle the combination of one bulb at F32 Watt and one bulb at F36 Watt 3) old electronic ballasts that need to be replaced.

I've had these endcaps and electronic ballasts in continuous daily use for about 8 years. Perhaps the endcaps become dry and more vulnerable to heat over time. I do have replacement endcaps on hand, but before I use them I'd like to find out what the cause is.

Currently I'm using the best bulb combination I've ever used - each ballast is running 2 bulbs, one Phillips Aquarelle TL89 F36T8 10,000K one Phillips Advantage F32 ADV850 5000K bulb, for a total of 4 48 inch T8 bulbs in the hood. The hood is well ventilated.

Some possibly important clues:

1) The endcaps that have fried are both on the right side of the aquarium feeding off of the red (hot) white and black wires from the ballasts (the endcaps on the other side where there was no meltdown feed off the blue wires coming from the ballasts).

2) Also, the first fried endcap was on an Aquarelle bulb; the second one today was on an ADV850. So I'm not sure if it's the bulbs. Perhaps it's the combination of the 36 Watt (Aquarelle) and the 32 Watt (ADV850) on the same ballast.

3) The first endcap to fry was fed by one ballast; the endcap that fried today is fed by the other ballast.

I'd sincerely appreciate your advice - not just for the health of my tank, but for the safety of my family and other pets!
 

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Discussion Starter · #3 ·
The lack of a fan is not the cause - I've used these end caps and the same hood with 4 T8 48" bulbs for years without any problems. Does anyone have any other suggestions?

For all of the years I've run these end caps and ballasts except for the last 6 months, I've used them with 4 identical F32T8 48" Verilux full spectrum bulbs. $ of the same bulb.

A few months before the first end cap fried, I mixed an F36T8 Aquarelle with an F32T8 ADV850 on each of the two ballasts - perhaps running an unbalanced load on each is a problem.
 

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Fishstein,

Did you say whether you were using ODNO? If not, are the ballasts mag or electronic? If using ODNO, the caps like yours are covering part of the lamps, which get much hotter than w/ NO. Don't know how good an idea that'd be anyway.

Ballasts can & do go bad. I worked in maintenance during college & replaced a lot. Normally they don't cause probs when going bad, but...
Problems w/ any ballast, esp electronic, could be intermittent - but usually aren't. But I saw a lot that'd work ok for a few days, then act up, then normal again.

Unless you have equip to test current draw, etc., it might be better to replace ballasts. How did the metal connections in the endcaps look (before melt down), and how were the pins on lamps? Make sure all connections are clean, tight and not corroded.

Do you have glass between water & lights? If not, it's a good idea. Were both ballasts same brand / model? If they're mag, don't know how flexible those are for running diff wattage lamps at same time.
 

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Discussion Starter · #5 ·
** Thanks so much for the info. See ** below for answers

Fishstein,

Did you say whether you were using ODNO? If not, are the ballasts mag or electronic? If using ODNO, the caps like yours are covering part of the lamps, which get much hotter than w/ NO. Don't know how good an idea that'd be anyway.

** By ODNO, do you mean over-driven normal output? I don't know how to set that up. My ballasts are simply standard F32T8 electronic ballasts, each designed to handle 2 bulbs. Perhaps the ballasts can't handle the 36 W bulbs or can't handle balancing a 36 watt and a 32 watt on the same ballast. I'll also ask my local lighting wholesaler - I hope they know.

Ballasts can & do go bad. I worked in maintenance during college & replaced a lot. Normally they don't cause probs when going bad, but...
Problems w/ any ballast, esp electronic, could be intermittent - but usually aren't. But I saw a lot that'd work ok for a few days, then act up, then normal again.

Unless you have equip to test current draw, etc., it might be better to replace ballasts. How did the metal connections in the endcaps look (before melt down), and how were the pins on lamps? Make sure all connections are clean, tight and not corroded.

** There may have been some corrosion after so many years, especially since I don't keep glass between bulbs and water. I'll have to check. Is it possible that all I need to do is replace the old end caps that might have corrosion on the leads?

Do you have glass between water & lights? If not, it's a good idea. Were both ballasts same brand / model? If they're mag, don't know how flexible those are for running diff wattage lamps at same time.

** I don't keep glass between the water and the bulbs because it really reduces the quality of the light getting into the water, and my tank, while it's not super deep, is a 75 gallon 48" L by 18" W and 18" H, and with this setup, and the bulbs I have, I can get great growth without using more lights and more power by not using glass. A lot of aquarists I know recommend not using glass between the bulbs and the water. The bulbs are about 6 inches above the water and the hood is very well ventilated by cutouts on the back and top of the hood.
 

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Do you have glass between water & lights? If not, it's a good idea. Were both ballasts same brand / model? If they're mag, don't know how flexible those are for running diff wattage lamps at same time.

** I don't keep glass between the water and the bulbs because it really reduces the quality of the light getting into the water, and my tank, while it's not super deep, is a 75 gallon 48" L by 18" W and 18" H, and with this setup, and the bulbs I have, I can get great growth without using more lights and more power by not using glass. A lot of aquarists I know recommend not using glass between the bulbs and the water. The bulbs are about 6 inches above the water and the hood is very well ventilated by cutouts on the back and top of the hood.
I'm sorry to say, but your aquarist friends reccomendations are making your tank electrically unsafe for the sake of a tiny light loss. Using a shield is pretty much necessary in a closed hood. If you're going to suspend lights above an open tank with a good air space, it might be better. I'm not sure who would tell you to suspend a light 6 inches above the water with no shield. This very well could be the cause of your short circuit - one fish breaking the surface of the water or a particularly high evaporation cycle would be all it would take to douse a fluorescent endcap with water. If you're worried about light problems, you can make a shield out of acrylic or fused quartz as they interfere very little with the spectra, but you need something in there to isolate the electrical system from the water area.

-Rich
 

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Discussion Starter · #8 ·
I'm using Coralife/Energy Savers water-resistant end caps (water-resistant, not waterproof). I am 99% sure the problem emanates from corrosion in the end caps.

I once dropped one of the end caps (when it was off) in the tank and though I let it dry for two days, that was the end cap that originally fried a few months later. As for the other end cap that fried, that was probably related to cumulative corrosion in the end cap over a period of 8 years. I think my best first bet is to replace the end caps with either new water-resistant end caps (I have enough spares to replace them all), or better yet, to replace them with fully waterproof end caps (just saw Ice Cap waterproof end caps for T8 here: http://www.aquariumplants.com/Ice_Cap_Endcap_T8_waterproof_single_tube_1_pair_p/ic738.htm ). Anyone know of any other waterproof end caps worth checking out?

Two things that I'd like to verify:

1) whether or not the ballasts can safely handle one 36 watt and one 32 watt on each ballast - in other words, can the dual F32 electronic ballasts handle the mixed wattage - everyone I asked in electronic stores when I bought them said yes. But I want to double check.

2) I have glass shields that go over the top of my aquarium water. However, they are very thick (about 1/4-1/3 inch glass) and do cut a lot of light, and are a real pain to keep clean and clear; they also keep the water temp higher and cut down on gas exchange to keep good oxygen in the water. What I might consider, if it was safe, is to use clear T8 tube covers the likes of which I have on my 48 in. F32 T8 Verilux full spectrum bulbs that I have in ceiling fixtures in my home office. These are clear tubes that cover the entire bulb and protect it from splashes, dust, etc. and protect people from a shattered bulb. The Question is whether these plastic sleeves, when used inside a hood (granted a hood with a lot of the back cut out for ventilation), keep too much heat around the bulb. Anyone ever use these clear plastic tube shields inside a hood?
 

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It's not a ballast/bulb combo problem and cooling fans won't stop it. The problem is the contacts in the endcap are loose. This causes a bad electrical connection, which makes for a high resistance and it sometimes arcs and always gets hot. You may be able to "squeeze" the female connectors in the endcaps a little with pliers to tighten them up. It's a common problem on molded endcaps for a lot of types of lighting.

Tommy
 

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Discussion Starter · #10 ·
Hi Tommy,

I was sure it was the end caps but I wasn't sure specifically what it was. I think you are right in the case of one of them (the one that recently blew), but the earlier one that blew had a dunking in the water and could have been corroded. I'm going to inspect all of them and replace them as soon as possible. I didn't think it was a ballast issue because I never had problems for months and the ballasts appear to be working fine.

Are you suggesting I bend the ends with a pier either outward or inward to make the connecting tighter with the leads in the end cap?
 

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Fishstein:

You should upgrade the endcaps as "moisture resistant" does not appear to be sufficient for your application.

Consider a workhorse ballast. You will get a little more light and a lot more flexibility for bulb combinations. (My WH 8 will run 4X T5HO)
 

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Discussion Starter · #12 ·
BlueRam,

Do you mean I should make the end caps waterproof and not just water resistant?

Also, is a "Workhorse" ballast a brand? My bulbs are not high output bulbs but high efficiency high energy efficiency low heat T8 bulbs. Where can I get such a ballast? How would it improve performance over my current ballast in a meaningful way? With my current setup I get plenty of high quality high photosynthetic-efficiency light to grow almost any green or red plants.
 

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Hi Tommy,

Are you suggesting I bend the ends with a pier either outward or inward to make the connecting tighter with the leads in the end cap?
If the endcaps are rubber like mine, gently squeeze the area that you can see the female brass connectors. This should make the connector ID smaller so it fits tighter on the bulb pins.


Tommy
 

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Discussion Starter · #15 ·
Hi Tommy,

I believe my end caps are made out of hard rubber (they are Coralife/Energy Savers water-resistant) and I know what you mean about squeezing the sides - however, inside the bottom between the rubber sides, there may be a plastic frame holding the leads - wouldn't this break if squeezed? I'm fairly certain most end caps are built with a plastic frame holding the leads in place.
 

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Discussion Starter · #16 ·
I tend toward adopting the simplest and least expensive solution that will work - taking everything into account, I think that the very simplest and least time consuming things to do are:

1) replace my end caps, either with the water-resistant ones I have (6 of 8 have lasted +8 years without problems) or, for $40 total, replace them with fully waterproof end caps. The problem appears to have originated from corrosion from moisture inside the end caps.

2) use polycarbonate tubes to cover my T8 bulbs to help prevent moisture from reaching the end caps and to protect the bulbs. This is simpler and easier for maintenance that using the glass tank covers I have.
 

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Discussion Starter · #18 ·
Thanks very much - which curve is the curve for optical polycarbonate? Is acrylic the same as optical polycarbonate?

These tubes are much thinner than eye glasses, so I image the transmission rate will be higher in all categories.

Also, how would the clear polycarbonate in those tubes compare with 1/4 to 1/3 in. aquarium glass?
 

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Hi Tommy,

I believe my end caps are made out of hard rubber (they are Coralife/Energy Savers water-resistant) and I know what you mean about squeezing the sides - however, inside the bottom between the rubber sides, there may be a plastic frame holding the leads - wouldn't this break if squeezed? I'm fairly certain most end caps are built with a plastic frame holding the leads in place.
I would think you're right about breaking the plastic.

Tommy
 

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Discussion Starter · #20 ·
Hi Rich,

Thanks very much - which curve is the curve for optical polycarbonate? Is acrylic the same as optical polycarbonate?

These tubes are much thinner than eye glasses, so I image the transmission rate will be higher in all categories.

Also, how would the clear polycarbonate in those tubes compare with 1/4 to 1/3 in. aquarium glass?
 
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