Open top aquaria and lights

[Mouflon44]

In researching my future "planted aquarium" I have encountered several mentions of "open top" aquaria. Am I to understand that if I suspend my lights from above, I can leave the tank without a cover of some kind? Won't the fish jump out?
Also, if I suspend the lights, do I need to get covers for the lights to prevent them from getting splashed by the fish or from evaporation?

What is the typical height above the water that most lighting types are suspended?

If my tank is 26" inches high, can I still get effective light using all fluorescent?

Thanks.... just working on some plans for a future basement aquarium.

[superjohnny]

Generally, when people have open top aquariums they have very powerful lights. The greater the distance between the light & the substrate the more time the light has to spread out so it's less intense. A lot of Amano style tanks are open top. To compensate he uses powerful metal halide lights. I have seen open top ~10g tanks that were very cool, but they had 30+watts of Power Compact light.

Yes, some fish will jump out. Nothing like finding a plattie that died months ago behind your stand. They get all dried out and hard... ewww.

There ususally isn't much splashing going on in any planted tank I have ever seen. Most of the time splashing comes from eels, crabs & things that like to try to get out.

Hope that helps

[djlen]

I have come to the conclusion that there is no advantage to an open top aquarium, unless you intend to plant with the idea that eventually the plants will flower in an immersed fashion(above the surface of the water). Some plants have beautiful flowers but will only flower if the stems are allowed to break the surface.
The disadvantages are fish loss(happens frequently), faster evaporation, and in my experience, surface scum.
I've been told by very reliable sources that keeping a glass top will not cut down appreciably on light intensity as long as you keep the glass clean.

Len

[Raithan Ellis]

In the past year or two, I had gotten the urge to try it on a couple of my tanks. Since then I've switched back to glass lids, but it was mainly because of the humidity that it added in my fishroom.

I've found that I was much more eager to throw my arm in the tanks for a little debris, rearranging this or that, tending to the plants and dosing nutrients without having lids. Surface scum was never a problem for me, but having decent surface disruption or overflows tends to help a lot.

The fish that were being kept were primarily angelfish, mollies, guppies and coryadoras. Only ones which I had any problem with were the mollies, it seemed like the females always wanted to escape.

It's defintally a nice looking tank style, but I'd only do it again if I had just one or two tanks to manage.

The loss of light from glass hoods is minimal, even if they are a little dirty. Just remember this for your lighting, every time you double the distance from a light source and your target, the intensity drops to a quarter of what it was when it was twice as close.

Cheers,
Raithan O. Ellis

[The Gipper]

I currently have an open top on my 120 gal planted tank. I have a custom made maple cabinet stand and canopy from a local craftsman. The canopy is 5-6 inches high, but has no top (lid), in other words, just the four sides. I have two 175w metal halide rectangular pendents over top. Without the six inch high sides of the canopy, the glare from the lights when looking at the tank from sitting on the couch or chairs was nasty.

I have lost one fish - and SAE that cleared the six inch high sides. My other two SAE's are still in there.

If I had a glass top, it would be brutal to feed and get into the tank. I would have to remove the canopy from the tank to get to the hinged glass top.

It's easy to feed, etc, which is what I wanted.

[superjohnny]

That's almost 3wpg and for a 120g tank that's a lot of light. Sounds cool, got any pics?

[The Gipper]

I'm in the process of buying a digital camera - will post some when I get it.

[Mouflon44]

Thanks for the replies. Now I have a lot to ponder. I like the idea of the Gipper's open top canopy. I may try some variation of this. My biggest obstacle is the size of the top. The top area will be 96x36. I could put several tops width-wise instead of lenghtwise I guess. I am still in the early planning stages at this point so I'll look into it a little more.
Being in the basement, the moisture aspect of an open top is a little concerning, although so far, the basement has never been the slightest bit damp or musty. It is actually not a true basement but a "daylight" basement.
Superjohnny, I clicked on your "pic" link and noticed one tank pic labeled "pre-uv" that was pretty clouded(algae bloom?). The other tank pics looked extremely clear. Do you attribute this to using UV? I am thinking on this too,(as well as a thousand other options) and was wondering if you have a strong opinion on UV, either pro or con. Thanks

[DIYMatt]

I have two open top plant tanks. One 75g with 2 - 175w MH's and a 45 corner with one 175 MH over it. I already owned the lights, or I probably would have gone with a little less wattage. I personally like them just for the aesthetics. I love the reflections on the ceiling. I doubt if there is really an advantge to it, though. But, if I was using RO flourescents, I think I would go with a more traditional hood. But, maybe not the glass lid. I read in an indoor gardening magazine that standard glass lenses on HID lights reduced usable output(or intensity?) by almost 20%!! More if its dirty. I will look for the magazine tonight and post if I find it and quote it. Also, I have actually sprayed water on an old flourescent tube and couldn't get it to shatter.

As far as fish jumpers, I have had very little problems until recently. The 75g has been up for 4 years it houses Pelvicachromis, cardinals, praecox rainbows, threadfin rainbows, formerly apistos, ottos, and Amano shrimp. The only things I have lost to jumping was the 6 of the danios I put into to originally cycle the tank, and a SAE. I am on my second pair of SAE's that I have had no problems with. Although, my bristlenose jumped once, but my cat alerted me to it, and she is still alive and thriving. Now, my 45 g corner tank is a little diferent. I started the tank about 4 weeks ago with existing plants, mulm, peat, and aged water from the 75. Last week I added 5 amano shrimp, 4 Ottos and my breeding pair of angels who will be the primary residents and lived an open top 30 g before. Well, I have come home to four of the shrimp crispy on the floor. And two nights ago, I awoke to a flopping sound(thetank is in my bedroom) and my cat meowing like mad on the edge of the bed. ONE of my parents had LEAPED! But, luckily I was able to get it back in he/she seems to be fine. A friend attributes the jumping to the 2 cups of Peat I put in the substrate. He says its toxic and is creating an "anaerobic" environment. I have no idea if this is true. Its strange but I think my fish owe their lives to my cat.!

Another "jump guard" idea is to make a 4-6" guard around the inside of the top of the tank out of acrylic. you can and build it yourself and its clear. I personally don't like the look of the large bulky wood hoods.

[JackDonkey]

Yes if you get an open top tank you must also get a lifeguard kitty :)

I had an open top tank for about 8 months and I lost 2 SAE's. One benefit of having an open top tank was once the clown loaches started jumping out you knew the CO2 was starting to dump. That by the way only happened in the evening when I was home so I managed to put the clown loaches back in, without getting stuck too.

I had a frame around the top of my tank that was made of 1"x6" the lights hung from that, so the lights were only a couple inches above the water, they never shattered, the reflecters have quite a few water spots though. There was a gap in my homemade frame on the front and rear, so the fish would jump and fall out the .2-.3" gap. I did have a truly open top for about 4 of those months, that is when the clown loaches would make it out.

[The Gipper]

I second what DIY Matt said about normal or even compact flurescence. I think I too would go closed top if I was using that type of lighting. I went open top because I wanted to go metal halide lighting, and only because of the metal halide lighting. With open top I didn't have to worry about fan cooling a closed canopy or hood.

A rim around the open top is a must, IMO, using whatever materials you prefer.

[RTR]

I have multiple open-topped tanks with the major pain being evaporation rate. Setting a rim around the perimeter as The Gipper suggests does block almost all the jumpers, but not 100%. My biggest losses are Amano shrimp when newly introduced to a tank. After the first few days I don't lose anymore. Even the Rainbows rarely leap out - which I was worried about.

It is pretty much an individual thing, but with the very strong lights is almost a requirement

[Hiame70]

I use 2 shoplights on my tank, with no cover, and have no problems. It's probably not the safest, but it's never been a problem for 4 years. I do lose water from evaporation more quickly.
I've tried glass tops, but my water is hard, and they end up getting are white & crusty w/ buildup.
Speaking of fish jumping out, I once slept on my sofa one night, m
(my tank is behind my sofa) and a pleco managed to leap out of a 1" opening and land on my face. Very Creepy!! Kinda painfull, they aren't exactly soft!

[Mouflon44]

How far above the water are your shop lights suspended?
Do you have a way of raising and lowering them?

[OrionGirl]

I have 2 open top tanks and 2 with lids. The 40 has 196 W of light, and glass lids for now. I will be building a canopy that has the lids sitting in a space on the canopy, and remove the glass lids. The canopy prevents jumpers, and I like the cleaner look of the canopies. My other open topped tank is a 20 that has plants in pots that grow emmersed (aluminum plant, mostly). The water is kept about 3 inches below the bottom of the trim. There are gourmies and an ACF in there, and no one has jumped. They will occassionally splash spectaculary--this past Sunday, my boyfriend was soaked by the frog as he walked by the tank. The lights are from a standard floor lamp with 75 watt grow bulbs.

Evaporation is a bit of an issue, but not so much that it's a pain. I add maybe 1 gallon of water/week, and usually less than that.

[DIYMatt]

I actually enjoy getting splashed by my Angels. I know they have spawned when start doing that. They are perfectly dostile and almost seem to interact with me(if thats possible) most of the time. But, man, from moment after they have spawned until I take the youngins out, they are visicous defenders of their young. I come near the tank at all and there is at least a splash. Or they ram the glass thrying to get at me. I almost stopped cleaning their tank because I thought they would hurt themselves attacking the gravel vac. they really put some force into it sometimes. Even when they splash, they break water and once one came all the way out of the tank when I was cleaning.

Anyways, my point was going to be, I'm happy you still have the frog, Oniongirl. My open top tanks are the main reason I don't have frogs, butterfly fish, or Killifish. I thought frogs could and would climb right out. I believe Butterfly fish and Killi's naturally will eat surface or flying insects. So, they out of instinct, they are liable to jump at stuff above the tank and out. But, I guess there is always an exception to every rule.

So, to further clarify, an open top tank may limit the types of fish you can keep in the tank.

[OrionGirl]

African clawed frogs are entirely aquatic. While they can move a bit on land, they prefer not to do so. She does not even try getting out--it was likely a gouramie that splashed. The frog spends most of her time kicking around the bottom, only surfacing to breathe.

For african butterflies, they are excellent jumpers. An enclosure of some kind--either a secure canopy or full glass lids--are a requirement. They will make it through the smallest of opening. Learned that lesson--on a covered tank that had a 1/2 wide, 3 inch long gap for the water return. Hatchets, bettas, and many loaches but specifically weather loaches are also excellent jumpers, but for them a 6 inch tall rim will prevent all but the most determined jumpers.

[Robert H]

You can also go semi open. There are compact fluorescent fixrtures such as the JBJ light that sit on legs about three or four inches above the tank. This allows you to see floating plants flower, and even enough room for plants that grow out of the water.

http://www.aquabotanic.com/abstore/media/48formosa.jpg

There is some danger of fish jumping out if you keep fish that are prone to do that. Not all fish are jumpers, in fact very few. I love open tanks, particularly truely open ones

http://www.aquabotanic.com/contest/2003/thumbs/21/3.jpg

http://www.aquabotanic.com/contest/2003/thumbs/21/5.jpg

It makes gardening possibilities endless!