Lighting options for Low Tech 20" Deep Juwel tank

[daizeUK]

The tank is a Juwel Lido, 24" wide and 20" deep from tubes to substrate.

Currently it has 2x T8 tubes with Arcadia reflectors. My aim is to increase this without entering high light territory.

My plans for the tank are a mineralised soil substrate and no additional CO2 or LC if I can help it. I'm aiming for a Walstad-style approach. I'd like to grow a mixture of stems, echinodorus, cryptocorynes, floating plants and hopefully a Monte Carlo carpet, hence I want a medium light that will successfully punch down to substrate.

These are the options that I'm thinking about:

Option 1: Stick with T8 tubes and Arcadia reflectors. I'm concerned that my tank is too deep for this option especially with floating plants and I won't get enough light down at substrate. I could possibly add a third T8 light on the rear flap.

Option 2: Same as above but upgrade my dirt-cheap Sylvania 6500K bulbs to higher quality Life-Glo tubes. I've been told these provide a much higher PAR output than standard T8 tubes, although they cost about 5x as much.

Option 3: Keep my T8 tubes and nestle a single additional T5 tube inside the front reflector, at a cost of around £35 for the starter unit. That is assuming that Juwel high-lite tubes can be used with a standard Arcadia starter unit.

Option 4: Upgrade to a Juwel T5 high-lite unit for about £75. I've seen the graph of T5HO PAR over distance so I understand that adding high-quality reflectors would put me into unwanted high light territory. Perhaps a bare T5 bulb at the back and a fair-quality Arcadia reflector at the front together with floating plants to provide shade would be a reasonable option. That is assuming my floating plants won't shrivel directly under high output T5's ?

Option 5: Switch to an LED unit such as 2x AquaAtlantis for about £75 per unit. I don't know anything about PAR output of these tubes but I know that the lumen output is about 1.5x a single T5 tube, or somewhat halfway between a T5 with and without reflector.

I'm not sure which route to take so thoughts and advice are appreciated!

 

[Tim Harrison]

Growing a low-tech lawn is possible in relatively low light but it helps to pick the right species - http://www.ukaps.org/forum/threads/low-tech-lawns.32597/#post-346432 but it still takes time.
I'm not sure about Monte carlo tho' since I've never grown it low-energy.
But that said I think you'll run in to trouble with some of your lighting options above...IME medium to high light is not usually compatible with low-energy, and I think to have a greater chance of success you'd at least need to dose LC which would give you more flexibility regarding your lighting options.

 

[Tim Harrison]

You could always give this a go as well...http://www.ukaps.org/forum/threads/...rted-planted-tank-a-how-to-guide.18943/page-3 Scroll down to post 56 - Low-energy lawns and DSM.

 

[JamieB]

I'm growing MC fairly successfully in a low tech tank with liquid carbon, seems to be going well, I'd imagine it'd grow well without the carbon if you keep on top of it. I only dose .4ml a day of LC as its a 19L tank (EasyCarbo)

 

[Tim Harrison]

It's getting the compact growth to form a decent lawn that's difficult in a low-energy tank, especially a Walstad tank, which is typically low light.
I've got more challenging carpet plants to grow in low-energy like glosso but it doesn't look very pretty and personally I certainly can't get it to form a dense carpet.
Strictly speaking once you start adding LC the tank becomes more of a high-energy system.

 

[daizeUK]

I was hoping to avoid LC because I'd like to keep shrimp. I already have another tank with double-dosed LC which I don't dare keep shrimp in. If I have to go hi-tech then I'll probably go the whole hog with this tank and inject.

I'm flexible regarding plants, I thought MC would be a good choice but I'll happily try different types including the ones you recommend in your thread Troi. Thanks for the link.

Any thoughts regarding T5 vs T8 for this tank, bearing in mind the depth of the tank and floating plants?

 

[Tim Harrison]

Darrel does well with T5s and a fairly long photoperiod; 12hrs I think, but his tanks have a large plant biomass (including a ton of floaters) to soak up the photons.
I've experimented with hi light and low nutrients in the water column, but high nutrient soil...it worked well for about 3 months then different kinds of algae started to creep in from the edges.
Being essentially lazy my motto is "minimum effort maximum gain" so I always go T8 lighting for a stable long term tank...about 1.5 watts/gallon, without reflectors (my current low-energy tank is about 18" high, below).
Reflectors can make a difference, but this sometimes means less wriggle room, but at 20" it might be a good option...don't be afraid to experiment to find the optimum; all our tanks are different.
I always use Arcadia lamps, a mix between the Original Tropical lamp and Freshwater lamp...together the colour rendition is awesome - really makes the colours on the fish and plants pop. I've yet to see an LED that competes. And I know light quality is a contentious issue but they give good growth too...unadulterated pic...

 

[daizeUK]

Thanks Troi, I love the healthy plants in that tank. So would you also recommend that higher quality T8 tubes are better for plants than my cheap tubes? If so I might go with option 2.

 

[Tim Harrison]

IMO, not so much cheap bulbs, but those that emit the right kinda light, or spectrum - I think quality matters as much as quantity - but it's a highly contentious issue here and elsewhere in the planted tank world, and I think my point of view is in the minority.
It's a whole can o' worms http://www.ukaps.org/forum/threads/spectrum-doesnt-matter-does-it.26717/

But bottom line is, I like the colour rendition, they're good quality, and the local Dobbies garden centre does them at relatively knock down prices.

However, most bulbs that we find aesthetically attractive can also, by happy coincidence, provide plants with the quality and quantity of light that they require. It's a function of the fact that the photosynthetically active spectrum and the visual spectrum are one and the same give or take a few nm; although humans and plants perceive them slightly differently.

The following link is for T5 bulbs, but, like Arcadia, other manufactures may do them in T8 as well...at least it'll give you further ideas - Cheap HO T5 fluorescent tubes - Update with photos | UK Aquatic Plant Society

P.S. you've also given me some food for thought - my plant mass has increased since I took that photo above, so I'm going to put my reflectors back and see how it goes...

 

[daizeUK]

Thanks for the info Troi. I've been mulling it over a lot .
Have you used T8's in a setup with lots of floating plants which provide shade?

I'm now thinking about adding a TMC Aquabar alongside my existing T8's. With the option of a dimmer switch for the LED's and adding/removing reflectors for the T8's this might give me a lot of flexibility for increasing/decreasing my light as needed. I could also swap one of my T8 bulbs to the Arcadia Tropical you suggested to counterbalance the blue hue of the Aquabar.

 

[Jaap]

Hi Troi,

do you have a journal or any other information regarding this tank?

Thanks

Darrel does well with T5s and a fairly long photoperiod; 12hrs I think, but his tanks have a large plant biomass (including a ton of floaters) to soak up the photons.
I've experimented with hi light and low nutrients in the water column, but high nutrient soil...it worked well for about 3 months then different kinds of algae started to creep in from the edges.
Being essentially lazy my motto is "minimum effort maximum gain" so I always go T8 lighting for a stable long term tank...about 1.5 watts/gallon, without reflectors (my current low-energy tank is about 18" high, below).
Reflectors can make a difference, but this sometimes means less wriggle room, but at 20" it might be a good option...don't be afraid to experiment to find the optimum; all our tanks are different.
I always use Arcadia lamps, a mix between the Original Tropical lamp and Freshwater lamp...together the colour rendition is awesome - really makes the colours on the fish and plants pop. I've yet to see an LED that competes. And I know light quality is a contentious issue but they give good growth too...unadulterated pic...