# Options on soil vs inert substrate



## Hoppy (Dec 24, 2005)

How are you determining that you are injecting enough CO2? Your plants look pretty good to me, and the Ludwigia looks about as red as it normally gets. Clay is not a good source of iron, compared to dosing Iron in the water, so I see no benefit to using clay balls unless you make clay ball fertilizer tabs with it. And, finally, I wouldn't bother with changing the substrate until you want to redo the whole tank. If you do good fertilizing and use enough CO2, the plants should be growing at the rate driven by the light intensity, which leads to: what lighting are you using?


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## Alphazygma (Mar 19, 2014)

Hello Hoppy,

Thank you for your valuable comments and questions.

As for the amount of CO2, I use two methods, a drop checker (from Ista) and the KH/PH table.
With those two, I'm a little above the recommended based on other comments to help fight the algae

I used to run my lights about 8hrs, for about 6 months until I introduced a plant that had the algae and hell broke loose.
Through the fixing time, I reduced time to 4hrs and started EI and raised the lights
Now I run the lights about 5:30 hrs, and brought the lights down again just last week.

My light fixture is a Finnex FugeRay Planted+, I've had it pretty much since the beginning (so, about 2yrs)

As for the Ludwigia, I just remember that it look very red when I first got it at the Aquatics Store.
Almost like this:








As for growth, the Ludwigia and the myriophyllum grow the fastest.


And just to reiterate, the bottom leaves start rotting soon and algae attaches to it, so I end up cutting and re-planting, so I cannot get bushy plants. (Stems)
I also notice roots growing in the middle of the plants, which lead me to believe that the plants roots are not getting to the root tabs and thus need to grow me to get nutrients from the water column.

If it is of any help, here are the dimensions of my tank (quite small)
Mr. Aqua 7.5 Gal bow front 
18"x9"x10"

I dose in alternate fashion (seachem liquid fertilizers)
* PO4, K, and N after water change
* Trace

And I dose 0.4ppm of FE almost daily.

Last note, as for the clay, I got Red clay and made tiny balls and let them dry, then added them as root tabs.


Thanks again.


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## Hoppy (Dec 24, 2005)

You are probably getting about 60-65 PAR with that light on such a low tank. That is enough that you need to have as much CO2 in the water as the fish can live comfortably with. Don't go by the KH/ph tables, they are not at all accurate, usually giving a much too high number. The drop checker will work to give you the courage to increase the CO2 bubble rate enough to get into the 20+ ppm range, but then you need to start slowly increasing the bubble rate. Increase it a small amount, watch the fish to be sure they are not starting to cluster at the water surface, or just lay still on the bottom of the tank. Watch the plants for a few days to see if they grow better - faster and more healthy looking. If the fish are ok, repeat this and keep repeating it until either the fish start showing distress or until the last increase didn't improve the plants growth. That gets you to the optimum bubble rate and concentration of CO2 in the water for the tank as it is at that time.

The green spot algae on the glass probably means you need to dose more phosphate (KH2PO4). If your water company water quality report doesn't show that you have a significant amount of magnesium in the water you need to add magnesium sulfate to your dosing, or use GH builder, like Equillibrium, after every water change.

Your water surface needs to be rippled over most of the surface, not enough to cause any splashing, just a noticeable rippling, to get as much oxygen into the water as you can.

And, you need to do a good job with weekly tank maintenance, so the water, the glass, the hoses, the filter, etc. are kept clean.

All of that so you can use high concentration of CO2 to avoid algae attacks, by keeping the plants growing as fast as the light is driving them to grow.

Or, you can hang the light about 6 inches above the top of the tank to lower the light intensity below that where you need so much CO2.


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## Nightshade259 (Nov 6, 2014)

I think that some plants are just finicky. When i added my ludwigia to my tank, i thought i killed it,but now it is a true red almost half way down the plant which is close to two feet.

As for substrate, I use pool sand with no root tabs.


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## Alphazygma (Mar 19, 2014)

I took some measurements tonight and here are the values, in case it is of any help.

NH4 = 0
NO2 = 0
NO3 = 10ppm
pH = 6.4 (while CO2 is running)
pH = 7.4 (no CO2)
KH = 3.8 degrees
GH = 6 degrees
PO4 = 2 ppm
Fe = 0ppm (was 0.4ppm when I dosed in the morning, I dose every morning)

If I were to replace the sand substrate with soil substrate (Azoo Plant Flower Bed), are there any I should be aware of?


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## kevmo911 (Sep 24, 2010)

If you're thinking of switching from sand to the Azoo because you much prefer the look of the Azoo, go for it!

But if you're hoping that it will cause your plants to grow better in any way, I think there are better ways to spend your money. Root tabs come to mind.

However, to answer your question, at that price, it had better actually include the nutrients it claims it has (other products, such as EcoComplete, make that claim and contribute exactly zero). If that's the case, you might end up with some ammonia spikes early on, so watch your parameters and be prepared to do water changes. I have no idea what the grain size is (I'd never heard of this product before you mentioned it), so it could be more difficult to get short-rooted plants to stay put, especially if you have active bottom-dwellers. My BN pleco used to pick fights with me over plant placement.


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## Alphazygma (Mar 19, 2014)

Thank you so much for your opinion, glad to know, I'll do more research.


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## keymastr (May 25, 2015)

I added a bit of Laterite gravel to my sand substrate just at the top layer because my sand was so fine that I did not think many nutrients were making it to the root zone. It seems to have helped although upping the co2 makes a far more noticeable impact.


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