# Crypt requirements and soil substrate: questions!



## skylsdale (Jun 2, 2004)

I'm planning an 80 setup I hope to get going in the near future. I want it to be very low-maintenance. The best method seems to be Diana Walstad's "natural" method, using an inch of soil for the underlayer, capped with an inch or so of gravel on top. I've spent a few days reading old threads in her forum over at All Wet Thumb, but there are a few questions I still have regarding the specific needs and habits of crypts and substrates that I thought I would direct to you guys.

I'm finally ready to start keeping chocolate gouramies (S. osphromenoides) again, and this tank will be setup for just them. I'm thinking of a pretty monospecific planting of C. cordata v. blassii, with very few other aquatic plants. The water level will be lowered so the tank is 1-2 to 2/3 full (total tank height is 23.25") and I would really like to have a lot of emmersed growth going on. Lighting will be anywhere from 1-2 WPG.

1. Now, Walstad recommends using gravel over the soil as it allows oxygen to reach the bacteria down in the soil. However, I can't really stand the uniform look of gravel--I much prefer sand that I collect myself. Does anyone know how much this will actually minimize oxygen transferring down to the soil? What if I did 2/3 of the tank with sand and 1/3 with gravel--would that provide enough oxygen? 

2. The soil I'm looking at using is a very basic potting soil I found at Wal-Mart, consisting of peat, forest material, and something else I don't remember (maybe vermiculite or perlite?). Would mixing in some peat with the soil be of any benefit? Would peat help soften the water or promote a more acidic water column? As for nutrients, it seems that after a few years crypts in this type of setup tend to slow down in their growth as much of the food get used up. Would it be beneficial to add Jobe's plant spikes into the substrate down the road?

3. The water I'll be using for this tank comes from a well, and here are the stats right out of the tap:

pH 7.5-8.0 (can't tell exactly with the test kit)
GH: 9
KH: 7

I would really like to attempt breeding chocolates again, but the best chances for that occur with a pH 5-6.5, GH 0-4, KH 0-5. I have thought about combining some RO/DI water, but according to Walstad it seems that the plants actually need the calcium, et al that comes from the tap water and using such a pure source of water wouldn't be beneficial. However, if plants are growing emmersed well enough, would that matter? What would you suggest?


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## MiamiAG (Jan 13, 2004)

skylsdale said:


> 1. Now, Walstad recommends using gravel over the soil as it allows oxygen to reach the bacteria down in the soil. However, I can't really stand the uniform look of gravel--I much prefer sand that I collect myself. Does anyone know how much this will actually minimize oxygen transferring down to the soil? What if I did 2/3 of the tank with sand and 1/3 with gravel--would that provide enough oxygen?


This is true for any substrate. You need to allow sufficient exchange between the water column and the substrate solution to result in anoxic environment. If you completely shut off this exchange, you substrate will go anaerobic and hydrogen sulfide will be created in the early stages. If you have enough roots in the substrates that carry oxygen rich water to the substrate, this may be minimized.

If I were you, I'd go with a more controllable substrate. IME and IMO, soil is too unpredictable. I would suggest you look into the use of peat, charcoal, pumice stone and green sand. I've posted about this combination in the past and it has proven to be stable. Above it, add a couple of inches of a good, porous substrate like flourite, flora base, eco-complete, or akadama.

I have used sand in the past and it shut off the needed exchange too much. Again, IME the sand has proven difficult. I'm sure there are plenty of people that will give you an opposite opinion though.



skylsdale said:


> 2. The soil I'm looking at using is a very basic potting soil I found at Wal-Mart, consisting of peat, forest material, and something else I don't remember (maybe vermiculite or perlite?). Would mixing in some peat with the soil be of any benefit? Would peat help soften the water or promote a more acidic water column? As for nutrients, it seems that after a few years crypts in this type of setup tend to slow down in their growth as much of the food get used up. Would it be beneficial to add Jobe's plant spikes into the substrate down the road?


Like other fertile substrates, its utility does become less over time for a number of reasons. Using a substrate as I've mentioned above will allow the substrate to recylce nutrients thereby extending its use.

I typically argue against Jobe's as they are not meant to be added to aquariums and can be potent. There are a number of formulas that allow you to roll your own root tabs and I'd look into those. Also, Amano has a line of root sticks that are designed for aquarium use and do work very well.



skylsdale said:


> 3. The water I'll be using for this tank comes from a well, and here are the stats right out of the tap:
> 
> pH 7.5-8.0 (can't tell exactly with the test kit)
> GH: 9
> ...


Sure, calcium, magnesium, etc. are all nutrients plants need. So the use of reverse osmosis without adding these back will result in nutrient deficiencies. The fact that a plant grows emersed is irrelevant in the sense that its aerial leaves will not obtain calcium, magnesium, etc. just like the submersed leaves. The nutrients need to be in the aquarium (either the substrate or the water column).

I would suggest you combine your tap and R/O to reach a target pH. The use of peat in the substrate will also help with this.

The important thing to remember with these types of tanks is that you need to keep an eye on the plants looking for nutrient deficiencies. As you are not adding all of the nutrients a plant needs through liquid fertilization, you need to make sure that those nutrients are present and available in the aquarium. This type of tank is not always low maintenance.


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