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laterite in the Philippines (was Long lived peat tanks)

Jonathan Uy <5js at durian_usc.edu.ph> wrote:
     
     >> I'm setting up my first plant tank in a 55g and plan it to be a low 
     tech tank with peat and sandblasting grit as the substrate.  This is 
     mainly because laterite is not available in my country and my water is 
     very hard and alkaline. Ph is 7.0, Gh is 24 dh and Kh is 12 dh on 
     cheap test kits. [snip]
     
     I am also planning to setup a 30g with clay and loam soil fertilized 
     by pond lily tabs for comparison purposes.  Read it from Jim Kelly's 
     article. Since there is no vermiculite available,  I wonder if this 
     local golden clay I found will be a good substitute?  Are all clays 
     rich in iron?  Can I test for iron by soaking the clay in a jar and 
     use an iron test kit? Haven't bought Iron test kit yet.
     
     I like to try the Dupla stuff but it isn't available here and having 
     it ship all the way to the Philippines would be too much.  <<

Kumusta Jon! My wife comes from Iligan City and we have friends there in 
Cebu.

You may have problems finding Dupla products and many other aquarium items 
we take for granted in Canada but you should be able to find places with 
natural laterite deposits in many places in the Philippines. I saw many 
deep red clay deposits in Mindanao. There is a large one just west of 
Cagayan de Oro where they use the clay to make ceramic pots. I don't know 
the Cebu country side but you should be able to find some red clay deposits 
especially if you ask the right people where to look. Light colored clay 
like your golden clay probably has much less iron than a red colored one. 
Not all clays contain large amounts of iron. The yellowish clay from the 
Philippines is probably high in aluminum oxides and hydroxides.

Look at growing plants in another way. It's all about providing the right 
nutrients in the correct proportions. The fact that certain substrate 
materials can provide some of those nutrients or bind cation nutrients at 
CEC sites is really secondary to the real concern of getting the right 
nutrients and providing a suitable environment for managing your plants. 
Often that means avoiding creating a mess with fine clays and soils or 
vermiculite flakes or fostering uncontrolled blue-green cyanobacteria or 
green water. The safest, low cost, starting method I can give people is to 
stick with plain gravel and the PMDD method using test kits. If test kits 
aren't available, a low risk, low cost method is to supplement nitrogen 
sources with a small amount of organic material like soil in the substrate 
and estimate iron availability by watching the plants especially the fast 
growing ones. Dosing potassium sulphate and epsom salts at 1/8 tsp per ten 
gal of water change will provide more than enough K and Mg. Ca could 
probably be dosed as low as 1/8 tsp per ten gal water changed or as high as 
2 tsp per ten gal water changed if you need hard water. If you have hard 
water, you probably don't even need to add any Mg or Ca as long as you 
change water frequently. With high fish loads you will probably have an 
excess of available phosphorus. At low fish loads without an alternative N 
source, you will probably be short of nitrogen. I think we almost always 
need to add potassium (K). 

I don't know what the easiest method is; it might be using a full 
complement of Lamotte test kits, the automatic Dupla nutrient dosing 
equipment and a Dupla CO2 controller. I'm not sure there really is an 
easiest method; they all are complicated in one way or another.

When I was in Iligan recently I set up a plant tank for my father-in-law 
using the local aquatic plants and small fishes which we caught there. I 
didn't know where to find peat so I used chopped up coconut husk fibers 
(small amount), red dirt and covered it with washed pea gravel used for 
making concrete. They tend to use sea sand which is full of coral bits and 
makes the pH high. I put the tank outside where it would get filtered 
sunlight and where the mosquitoes could lay eggs in it for fish food. The 
local plants I found included a submersed plant with finely divided like 
Myriophylum but with 6 branches at each stem node and a single primary 
stem. I found a picture of it but can't recall the name. There was also an 
emergent plant that looked a lot like an Hygrophila species, something else 
called "water grass" with small round leaves and kangkong which has cordate 
leaves about 3-4 inches across. Kangkong leaves and stem resemble a small 
version of philodendron but the plant is used as feed for pigs and as 
greens for soup. It's like eating spinach but with a tougher texture. The 
leaves are usually emergent and I don't know if it would grow fully 
submersed. I used emergent plants because I couldn't rig CO2 or explain how 
to use a yeast method safely.

Last I heard the plants were still growing. They had added a bunch of 
tropical fish but these had died since I had told them not to add food. I 
advised them to feed the fish if they were going to keep some but not to 
try to keep too many. My plan was to have a self-sustaining population of 
small, local fish fed by mosquitoes but this might not have been realistic. 
The plan was to add fresh water each day which should have supplemented 
most nutrients including Fe I hoped. 

I saw algae eaters in a local waterfall swimming hole which resembled SAEs 
but the coloration looked different. Impossible to catch without a trap I 
think. The small fish I had resembled some type of killie fish and had two 
bluish spots on the body, one about half way and the other near the tail. 
They figured these were Tilapia fry but I'm not so sure. Definitely there 
were Tilapia fry in that pool since my father-in-law raised two to a 
moderate size.

Where did you find peat or what did you use for a substitute?

ok, enough... ;-)

Steve in Vancouver