Too much sunlight - El Natural

maxthedog123 · 03-06-2012, 06:54 AM

I am setting up a new NPT 46g bowfront el natural tank. This will be my 3rd el natural tank.

My question is this - the tank is going in a front window in my house that faces South. This time of year - when the pear tree in the front yard doesn't have any leaves - sunlight comes in the window from about 8am-12pm. It hits the whole tank for about 2 hours of that time - partial the other times, but still direct. When the leaves come in, the light will be diffused.

I have a 2x21w NO T5 fixture I am planning on running from about 4pm-10pm, so about 6 hours after that. (Maybe more in the summer when the leaves come in.)

What are your thoughts? Is this going to be too much sunlight on the tank? I can choose to leave the shade closed, but it is pretty much an all or nothing decision when I leave my house in the morning.

maxthedog123 · 03-06-2012, 07:08 AM

I will also add that in addition to loads of plants I have going in there later this week I also put an plastic grate on the back at the top. I plan on a full row of spider plants and philodendron that will be in the back growing emersed for "aerial advantage".

maxthedog123 · 03-06-2012, 05:07 PM

Submerged the tank tonight. I planted Vals, a sword, Hygro kompact, H. polysperma and some dwarf grass from other tanks. I have a large box of plants coming to my porch on Thursday to really blow it out. Pictures soon.

Looking forward to thoughts on the sunlight....

Hayden · 03-06-2012, 05:31 PM

I have my tank under an east window. The sun shines directly into the side of the tank from about 8 to 9:30ish. I have to scrape lots of algae of that one pane while none of the others really get any. This is my first planted tank so I'm not in a position to offer any advice, but I thought you might find this helpful.

vicky · 03-06-2012, 08:21 PM

I have/had four different tanks in south facing windows. Two had terrible algae. Taping some white paper to the window side of the tank helped a bit, and wasn't very distracting. The other two have no algae to speak of. Shrug. Don't know why. Perhaps a lighter bioload and a lower soil load. Or perhaps some other reason.

You may have no trouble at all, or may have seasonal trouble. Perhaps you will not need lights on during the day. Each tank is unique and presents its own problems with achieving balance. Be patient and you will get there.

Yes! Pictures! New tanks are so much fun.

JeffyFunk · 03-07-2012, 03:53 AM

Most of my soil substrate tanks I have in windows, including south/eastern exposures. The important thing with sunlight, as explained in 'Ecology of the Planted Aquarium' by D. Walstad, is to prevent sunlight from directly hitting the soil sub-layer. This will prevent photoxidation of Fe(III) in the substrate, making it move available to algae. To prevent this, I cover the bottom 2-3'' of my aquariums with black tape. Even with this precaution, it is not unusual to get more algae on the side that gets directly exposed to sunlight. In my tanks, I always end up w/ a little bit of green hair/fuzz algae, always right above the substrate on the side directly exposed to sunlight. It doesn't seem to harm any of the plants and is easily removed (although it then just grows back again...).

Michael · 03-07-2012, 06:01 AM

JeffyFunk's comments are right on. My "sunniest" tank also has hair algae just above the substrate on the window side.

That tank generally has more algae than my artificially lit tanks. It is not excessive, and I manage it by glass scraping and removal of the hair algae. Except I can't do that right now because my paradise fish in that tank just spawned!

maxthedog123 · 03-07-2012, 08:23 AM

Here you can see what I've planted so far as well as the awesome piece of wood I found (and soaked for days).

Lot's of sun with the window open and no leaves on the tree. The gravel extends over the frame, but none of the soil is visible. Should I still cover the exposed gravel, or do I only need to worry about the soil?

I opened the window for a bit - the sword started pearling like mad about 2 minutes after the sun hit it. I need to close the window so it doesn't cook them I guess.

My plan when the leaves come in is to run the lights from like 5-10pm and see how that goes with diffused light coming in the window.

JeffyFunk · 03-07-2012, 09:48 AM

A couple of comments... (1) Only the soil sub-layer needs to be protected from sunlight. The gravel should not have any organic matter in it to oxidize so sunlight is not a problem with gravel. (2) I really woudn't worry about the temperature of the tank in the wintertime from exposure to direct sunlight... If it is a problem, it would be for more delicate plants from colder climates like java ferns and bolbitus. I don't think sword plants would have a tough time w/ elevated temperatures. In the summertime, that could be a problem though. The temperature could easily be controlled by using a fan to promote evaporative cooling. I would just make sure the fish are comfortable and not breathing at the surface (unless they're supposed to breath at the surface...). And (3) Sword plants get HUGE!!!! Be prepared for it to dominate your tank. (That's not necessarily a bad thing, as long as you realize that and plan accordingly...)

maxthedog123 · 03-07-2012, 10:25 AM

Cool - I won't worry about the gravel then. I might put one piece of tape back there just to make sure - a very, very small amount of soil could be peeking out back there, but I'm not sure.

I know swords get big - that is a "baby" from the sword in my 55g!!

In about 3 weeks, that tree you see out the window will block almost all of the sunlight. It will only be diffused light until late October. That's why I have been asking about the sunlight - in the winter this tank will get directly sunlight from 8am-12pm. It looks like the consensus is I may have algae issues with that much light.

I will start a build thread as well when I get plants delivered on Friday. I am curious if I can beat the algae even with that much light. I have more spider plants to go on top as well as $60 bucks worth of plants coming. Among other things, I have 6 bunches of H. corymbosa, 2 more kompact hygro, 6 bunches of mixed Ludwigia, more dwarf hairgrass, java fern and some micro swords. I have a feeling I will have some plants to put in my other 4 tanks with all that is coming. I am going all in with this one as low tech. The more I think about it, I may indeed be able to out compete the algae with all of these plants!!