[Wet Thumb Forum]-Light limits?

[Phil Edwards]

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]

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.

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[dwalstad]

[quote]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.


Roger Miller

Hi Roger,

It was great talking to you at the AGA Convention!

About keeping a lot of species without CO2 injection. I think it helps to keep them in pots where their roots don't have to compete with other plants.

It also helps to have a lot of well-fed fish.

For many years, I got letters from hobbyists asking how they could bring down the alkaline pH in their natural tanks and ponds. I have the same problem-- alkaline pH. I tried out chemicals (vinegar, HCl, phosphates), but nothing worked long-term without creating major problems.

It was only a few months ago that I remembered that when I had tanks packed with cichlids I often had an acidic pH.

So lately I've added more fish and more light and... guess what? The plants are doing better, and I'm growing species that I've had trouble with in the past---C. blassi, Rotala macranda, Ricci, etc.

Diana Walstad

[Roger Miller]

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

[imported_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!

[dwalstad]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>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!<HR></BLOCKQUOTE>

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

Diana Walstad

[plantbrains]

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

[imported_Piscesgirl]

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.

[dwalstad]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>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?

Hi Roger,

I don't know what's going on in Baltimore, but its a moot point, because I'm too busy.

Sorry I didn't get to your question sooner, but I wasn't sure what the question was. Also, the subject of substrate iron required a little thought and mulling over.

In any case, I'll post something in the substrate iron folder as soon as I get some time (I don't know about you, but I'm getting lost in all these folders).

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

Diana Walstad

[The Bishop]

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.