Lighting a deep tank ...

[trennamw]

Just 24", but it does seem harder than lighting one 18" deep. Trying to keep it medium light, low tech.

I've read, go with a high intensity light even for low tech because by the time it penetrates it's not high light anymore ... And oh it's fine with the same light ... And everything in between.

I used to do well doing the Oregon thing - we get away with full sun plants in shade outside in the summer, because of our long days. So I ran my 29 with just the marineland LED that came in the kit, with a 14 hour photoperiod. All was well for almost a year. Then I added medium light plants, Osmocote tabs, and a little excel, and added a second light fixture.

But I moved everything to a 56 column and it's not bad but it's getting iffy. I have both a touch of algae and plants seeming a tiny bit light starved. (The leaves facing the side by the window are fine, others are not).

I want to keep it at low tech medium light. Currently it has one 24" t8, and two marineland led fixtures. Running 12 hours.

I'm wondering about putting a light behind the tank, reducing the overall photoperiod, and letting the behind the tank one go a little bit midday when nobody is home to see it looks weird. Then the light is a few inches from the background plants (ruffle sword, cabomba) that need it.


Sent from my iPhone with three hands tied behind my back.

 

[Hooked on Fish]

G'day trennamw,

yep you're right, it is definitely harder to light a 24" deep tank. Having said that I wouldn't be trying to grow carpet plants at that depth. It might be better to use plants that have lower light requirements. Instead of carpeting plants I've use Crypts to fill in the front of the tank with Swords in the middle ground and bunch plants in the background. I've also added a few Anubias attached to driftwood that I've positioned on rocks to raise their height in the tank.

To save energy and get a good light spectrum I've installed 2 x PlantGlo 120 LED lighting system that I've put on a timer to create a siesta lighting schedule (5 hours on, 4 hours off, followed by 5 hours on again). The reason for this is simple, after about 4-5 hours the plants will have used all of the CO2 in the water column and stopped photosynthesizing. By turning the lights off for about 4 hours the CO2 will replenish. From the plants point of view there is no point having the lights on if there is no CO2 in the water. The only thing that will flourish under low CO2 levels is algae.

Cheers

 

[trennamw]

G'day trennamw,



yep you're right, it is definitely harder to light a 24" deep tank. Having said that I wouldn't be trying to grow carpet plants at that depth. It might be better to use plants that have lower light requirements. Instead of carpeting plants I've use Crypts to fill in the front of the tank with Swords in the middle ground and bunch plants in the background. I've also added a few Anubias attached to driftwood that I've positioned on rocks to raise their height in the tank.



To save energy and get a good light spectrum I've installed 2 x PlantGlo 120 LED lighting system that I've put on a timer to create a siesta lighting schedule (5 hours on, 4 hours off, followed by 5 hours on again). The reason for this is simple, after about 4-5 hours the plants will have used all of the CO2 in the water column and stopped photosynthesizing. By turning the lights off for about 4 hours the CO2 will replenish. From the plants point of view there is no point having the lights on if there is no CO2 in the water. The only thing that will flourish under low CO2 levels is algae.



Cheers

Hey thanks!!

That's the most cogent explanation of the siesta I've encountered. It's so obvious but I just didn't get it before (the reason extra long photoperiods help in a Oregon gardens is the unlimited co2).

Is this true even with Excel? I add a half dose once a day. I thought it has a half life of 12 hours.

Right now it's Java fern, anubias, jungle Val, and crypts on the side away from the window and swords on the side by the window.

Ruffle swords are struggling a little but perked up when I stopped letting the tannins build up so much from new driftwood. Misc swords are thriving, red Rubin swords lost all their pre-me leaves but have put out two new ones a week. Anubias give me one new leaf every 2 weeks. Cabomba has about had it but I'd not placed it well having been about done with it anyway, it makes such a mess.

I keep thinking water sprite but everyone has different opinions on its light requirement. I'd love to float pennywort-my other tank that's unfiltered has like half an inch a day to donate-but I think excel makes it melt.

There are Osmocote root tabs but when they wear out I may follow a low tech dry fert approach I read on Bare Report ... Not EI, just equilibrium and 2 others in small amounts.


Sent from my iPhone with three hands tied behind my back.

 

[Hooked on Fish]

Thanks for the compliment. I wish I could take credit for that information but I read about it in Diana Walstad's book "Ecology of the Planted Aquarium". She also has a good section on light spectrum and it's affect on aquatic plant growth.

As for your question about Excel (Glutaraldehyde) I suggest you read "Carbon in the Planted Aquarium" http://www.seachem.com/Library/Articles/Carbon_in_the_Planted_Aquarium.pdf

Basically I use both approaches. The bacteria and fish expiration definitely produce a good source of CO2 however Glutaraldehyde also has the added benefit of inhibiting algae (see Algae Control With Flourish Excel | Aquariums Life).

A build up of tannin in the water will definitely reduce the amount of light reaching your plants. As I have potting soil in my substrate I have to manage this regularly. To handle it I have a secondary filter stuffed with filter floss (pillow stuffing). If tannin becomes noticeable I add about half the recommended dose of a flocculating agent. It doesn't seem to bother the fish and it clears the water fast.

As for dosing with liquid ferts, I try to avoid it. I did add an iron supplement at one stage but it encouraged too much algal growth. I think it's better to keep the nutrient out of the water column and in the substrate. Another useful way to manage water nutrient build up is fast growing plants, especially emergent plants. They have the added advantage of being able to source CO2 directly from the atmosphere.

Enjoy.

 

[trennamw]

I've read Walsteads book a few times and just didn't have that light bulb (har har) moment on the siesta. I know I knew it but didn't really really process it yanno?

I'm definitely not switching over from inert sand any time soon, so it's either Osmocote or dry Ferts. I have read a lot of Walstad, Barr, walstad v barr, and think I'll give Barr a shot next. He's got one approach that's sort of "walstad plus a dash of 3 things each week - two dashes if you use Excel" for lower light, fewer water change, tanks.

Thanks for the link about Glut! I'm a very good terrestrial gardener and generally get sciencey stuff but a lot of the aquatic gardening just isn't linking up in my head.


Sent from my iPhone with three hands tied behind my back.