# [Wet Thumb Forum]-Light limits?



## Roger Miller (Jun 19, 2004)

When I was keeping CO2-less tanks I found it impossible to grow a reasonable variety of plants in tanks with bright light. All but one or two species would waste away. The pH went very high (9+) under bright light, so I think that the best-adapted plants outcompeted the others.

I was curious what light levels people have been able to maintain in planted tanks without CO2 and still grow a variety of plants.


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## Roger Miller (Jun 19, 2004)

When I was keeping CO2-less tanks I found it impossible to grow a reasonable variety of plants in tanks with bright light. All but one or two species would waste away. The pH went very high (9+) under bright light, so I think that the best-adapted plants outcompeted the others.

I was curious what light levels people have been able to maintain in planted tanks without CO2 and still grow a variety of plants.


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## imported_RTR (Sep 11, 2003)

If your pH went 'way up, did one of the survivors happen to be Val or other plant capable of splitting out the carbon from carbonates/bicarbonates? 

Some of us don't do wide (define "reasonable"?) varieties of plants so cannot easily answer your question - I get uneasy at max six species in a 55 - it starts getting "busy" to me.

I also don't do bright light without carbon supplement - about 2.6 W/gal is my top.

"Where's the fish?" - Neptune


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## Roger Miller (Jun 19, 2004)

RTR,

Yep. Vals were one. Anubias nana, Crypt wendtii and Ceratophyllum demersum were others that made it.

"Reasonable" is probably whatever you find sufficient. I wasn't happy with being able to grow only three or four plant varieties in a tank. I thought that was unreasonable.


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## Kevin Jones (Apr 4, 2004)

I've had non-CO2 tanks at about 3 - 3.3 WPG with ultra soft (less than 5ppm hardness) where the pH would shoot to about 7.8

crypts, echinodorus species, sagitaria, mayaca sp, ferns, mosses, water sprite, and lillies did well.


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## Roger Miller (Jun 19, 2004)

JoneZay,

That's interesting. 7.8 is not that high as pH goes -- there would still be CO2 in the water. Where was the CO2 coming from?

I wonder if 3-3.3 watts/gallon is not enough light to drive plants into using bicarb.


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## MarcinB (Apr 16, 2004)

I don't have much experience with low tech tanks, but I'd shoot for about 2 WPG.

150L (40G) planted tank
click here for photo
Rate my tank!


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## imported_Svennovitch (Feb 1, 2003)

I have never tried a low tech, bright light tank before. But I do have a tank with only 18 W over a 20 gallon tank. And Anubias, Crypts, Hygrophila polysperma and Vallisneria are growing relatively well. Not that fast and strong but growing...

Sven


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## Kevin Jones (Apr 4, 2004)

I think the lower pH of my tanks was attributed to the peat being used in the substrate. that and to induce the apistos to spawn I would occaisionally use peat-soaked water in water changes.

Interestingly enough, I always had success getting the SA dwarfs in those tanks to spawn and rear their young.


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## Roger Miller (Jun 19, 2004)

JoneZay,

It sounds like that tank had three sources of CO2 -- the respiration of the fish, the CO2 produced by the breakdown of the substrate and the action of the acidic peat on any bicarb in the water. Together they were enough to keep the plants from using up all the CO2 and pushing the pH over 8.4


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## Phil Edwards (Jan 22, 2004)

I have 2 40w T12 over my 55 and things are stable. I haven't done much in the way of water changes, but I top off evaporation.


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## Vicki (Jan 31, 2003)

I have a very stable 20 high with 55 pc watts over it that has no added CO2 of any kind. I don't grow a wide variety of plants, though--several species of crypts, one sword, an anubias barteri v. barteri, java fern, java moss, watersprite and hornwort all do well. And duckweed. This is the tank where I maintain plants I don't want in most of my tanks, like the watersprite, hornwort and duckweed, for use when I need them for a new tank or a fry tank.

http://www.wheelpost.com


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## dwalstad (Apr 14, 2006)

> Originally posted by Roger Miller:
> When I was keeping CO2-less tanks I found it impossible to grow a reasonable variety of plants in tanks with bright light. All but one or two species would waste away. The pH went very high (9+) under bright light, so I think that the best-adapted plants outcompeted the others.
> 
> I was curious what light levels people have been able to maintain in planted tanks without CO2 and still grow a variety of plants.
> ...


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## Roger Miller (Jun 19, 2004)

Hi Diana,

I enjoyed talking with you in Dallas and I hope to have that opportunity again in Baltimore. Are you planning a trip north?

I usually keep the fish loads in my tanks very low compared to most people. I can see how higher fish loads would help. The substrate in those tanks was 5 or 6 years old at the time, but it wasn't anything but blasting grit. No doubt more stable organics in the substrate (or pots) would help.

Now that I have your attention, would you like to comment on the "substrate iron" thread that I started in this forum soon after the Dallas convention?

Roger Miller

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_"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein_


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## imported_Piscesgirl (Feb 19, 2004)

This topic is of great interest to me, although I have taken the plunge into various forms of DIY CO2 and am about to go into pressurized--but I still somehow want high light, no CO2 to work!


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## dwalstad (Apr 14, 2006)

> quote:
> 
> Originally posted by Piscesgirl:
> This topic is of great interest to me, although I have taken the plunge into various forms of DIY CO2 and am about to go into pressurized--but I still somehow want high light, no CO2 to work!


There are many ways to having aquariums that give us pleasure.

Diana Walstad


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## plantbrains (Mar 11, 2003)

My sister's 10 gal has 3w/gal, it's been running for a 7-8 years.

I grow hairgrass and other so called hard plants etc. 

But I will say the balance between fish waste and plant biomass needs to be achieved prior.

I add the tougher plants later, generally 3 months after. And it takes several months for some plants to fill out.

I'll pick on the easy to grow species removing a little at a time and slowly let the other species, Gloss, Hair grass etc grow in.

I add a bicarb user in every tank, so the water is softened over time but still gets a little from the tap water and the Onyx sand.

P palustris has much nicer leaf morphology when grown in non CO2 tanks vs CO2 enriched.
E azurea grows slower(thank the lord).
Many red plants will become extremely red in these tanks, the NO3 levels and the NH4 are so low but growth is slow so the plants can maintain a low N level uptake that balances well with the input. 
I find it much easier to maintain plants at low NO3 levels in a non CO2 tank, CO2 tank plants suck the NO3 out very fast makign it difficult to keep up with their needs without going outside the "red range" with NO3 dosing.
Dosing pumps, daily etc can get around it but it's a real PITA.

Regards, 
Tom Barr


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## imported_Piscesgirl (Feb 19, 2004)

You add a bicarb user = you mean like Vals? I also wonder about smaller tanks b/c as my understanding is that they require higher light levels than comparable larger tanks. Is this not so? I've been running a 10 watt CF screw in 6500K (not the spiral kind, they are for fish tanks) over my 2 gallon hex with no CO2 and it's done remarkably well with a whole mess of plants (hygrophila difforis, Ludwegia Repens (narrow leaf), stargrass, E. Tennelus). Now, I did use Excel on and off, but not consistently. No algae whatsoever. Onyx sand and gravel in there.


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## dwalstad (Apr 14, 2006)

> quote:
> 
> Originally posted by Roger Miller:
> Would you like to comment on the "substrate iron" thread that I started in this forum soon after the Dallas convention?
> ...


Diana Walstad


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## The Bishop (Mar 11, 2004)

I have noticed in my experimentation with different personal setups that CO2 injection is more of a liability than anything else. Sure, your plants grow superbly--but the fish aren't always happy and let's be honest, CO2 systems are a pain in the butt to monitor and maintain. The best part is how a CO2 tank will not hesitate to suck every nutrient out of any given substrate and subsequently cause a collapse.

I have 5.5 watts/gallon of 10000k compact fluorescent over a 46 gallon non-CO2 tank, with upwards of two dozen species of both "demanding" and "easy" plants. The substrate is 1.5 inches of soil under 1.5-2 inches of gravel. My Cabomba furcata is lipstick red, as is my Ludwigia palustris. The two Potamogetons I am growing in the tank bubble when they get within six inches of the surface, and the Ranalisma is going nuts in the foreground. The pH is around 7.6 (standard Detroit-area water).

The fish bioload in this tank is MASSIVE (about 15-20 species), and they are all as happy as can be. I had Aspidoras menezesi spawn in this setup about this time last year.

In my opinion, the trick is to let carbon be the limiting factor. This is why I use soil substrates (the plants have to work to get at the CO2).

I have had absolutely no trouble with this tank. It is algae-free, and the plants do not grow a foot a week, but they grow enough to keep me happy.









The path of least resistance will seldom lead you beyond your doorstep.


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## hubbahubbahehe (Mar 29, 2004)

yea soil is pretty awesome


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