This isn't supposed to work so well.

[dskidmore]

Oh, how I wish I had a good digital camera. I looked at my tank a few days ago, and it seems like the plants in the top four inches of my aquarium are pearling!

I don't have a big budget, or a scrapyard of parts to go over, so I have a very minimalist aquarium.

Setup:
75 gallon aquarium
2x 40Watt shop light, no reflector
Heater
4' bubble wall
small sponge filter.
"paving sand" substrate (chosen for the mixture of grain sizes)
a motley crew of fish I would not have selected to swim together.

No CO2, no fertilization, no special substrate.

I'm not sure if it's the excessivly large bubble wall that's causing oxygen saturation, so the little the plants are putting off won't disolve, or if the plants are actually doing that well.

Given, some of the plants in my initial purchace could not survive in these low-light conditions, but those that have appear to be thiving. I have a little forest now of hornwort, that the fish like to hide in. (I'll have to do something about that, so I can see the fish.) The jungle val is tall enough to be in the pearling group. The corkscrew val keeps getting thicker, the other (crystal?) val has put off several babies on runners. My poor crypts rescued from a previous tank are starting to spring back.

Just thought I'd give those with budgets like mine some hope! This tank breaks a diffrent set of rules than my old 10 gallon "window ledge" aquarium, that one did pretty well too.

Thoughts:
Turbulance/air supplies are usually nixed by the high end planted aquarium folk, but an air pump does serve to keep the O2/CO2 balance in your aquarium the same as it is in the air. If you are not injecting CO2, this is actually a good thing, reducing day/night pH swings, and bringing atmospheric CO2 into the aquarium during the day, and O2 at night.

Getting the right nutrient balance to keep algae down is difficult without a larger budget, but possible. Check the nutrient balance in the food you feed. Use RO water from a grocery store vending machine to decrease total nutrient levels if your tap water is too high.

I am planning to start fertilizing sometime. I need to get another light and a few more test kits first. I still going to try to get away without injecting CO2.

[Crusis]

I don't think injected CO2 is a neccessity, just that it enhances the growth of the plants overall. I vent from my CO2 diffuser directly into the HOB filter, which sucks all the tiny bubbles into the impeller and mixes it up nicely.

Not only has this been like growth hormone for my plants, it's lowered the PH of my tank from 8.3 to 7.6, which I think is making my fish very happy too. (Various Tetras, Gold Barbs, couple of Otos, Skunk cories, kuhli loaches.)

I think if you fertilize with high light levels, you're going to have algae issues without CO2 as without the plant growth boost the plants won't be taking in as much of the nutrients.

[travis simonson]

Because of the bubble wall your tank may be close to the saturation level of O2. It doesn't matter if you're injecting CO2 or not, once your water column reaches 100% O2 saturation levels you will likely start to see pearling from your plants. Very cool This is similar to the pearling you often see after you do a water change. The tap water is very close to 100% O2 saturation when it goes into your tank so you see all of the bubbles. Nice work

[dskidmore]

Originally Posted by travis simonson

Because of the bubble wall your tank may be close to the saturation level of O2.

Or at least close to the saturation level of atmospheric gasses. I'm probably pumping in more N2 than O2 or CO2. I could get higher concentrations if I pumped in refined gasses, but nature doesn't seem to need that, neither does my aquarium.

I'm thinking of eventually replacing the bubble wall with some powerheads. The otocats I want to add tend to like high current, and I don't think the bubble wall will quite cut it. If I aim one powerhead at the surface, I should get almost as good gas exchange.