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Re[2]: laterite in the Philippines

     Hi Jonathan,
     We just returned from Cebu/Mindanao this July; too bad I didn't know 
     you then because I would have visited you in Cebu City.
     As for substrate, this will depend mostly upon two factors: which 
     plants you will want to grow and what chemicals you can get access to. 
     Can you get Seachem Flourish there? This is a relatively inexpensive 
     chelated iron fertilizer which also has other trace nutrients. I don't 
     know if this is over your budget or hard to find. Another alternative 
     is to get some chelated Fe trace element mix. This may be hard to find 
     in the Philippines but it is worth trying to locate it as this is the 
     cheapest way to get this kind of fertilizer. If you are really stuck, 
     I can send you some by mail.
     It is also good to use an iron rich soil as many kinds of plants 
     especially Cryptocorynes, can get iron from the substrate. The problem 
     with soil and clay especially, is it can make a mess when you uproot 
     plants. If you get cloudy water, you may need to drain all your water 
     and replace it and that can be tricky with fish in there. Still, I 
     think the improvements with soil are worth it IF you are careful. It 
     is best to find an iron rich soil such as the red soil which you 
     should be able to find if you have a friend from Mindanao or if you 
     can find it on Cebu. I think it must also be there but where? Even if 
     the soil is light red or brown, it will have enough iron. Use a 
     natural soil, not something you get in the garden store. The garden 
     store soils are very, very fertile and that is not good in an 
     If I were you I'd put a 1" layer of soil/clay in the bottom of your 
     tank and then cover this with a 1" mixture of 50% by volume of peat 
     and sand. This is about 1:10 ratio by weight. Cover that with 1" 
     coarse sand or fine gravel of about 2-3 mm in size. Try to avoid beach 
     sand as it contains lots of coral and shells and is not ideal for 
     Crypts (too much calcium). Beach sand also may contain algaes even if 
     it is long dried.
     For chemicals you need to find MgSO4 (Epsom salts), KSO4 (potassium 
     sulphate). Is it possible for you to obtain an analysis of your local water 
     from the water utility company there? This will tell you if you need to add 
     Mg or calcium (Ca). It is very probable that there is enough Mg and Ca 
     already in your water. The problem with water from the tap in Cebu is that 
     it may contain chlorine or even chlor-amine to inhibit bacteria. You can 
     remove chlorine by letting the water sit in a bucket or container for a day 
     or so but chlor-amine is harder. Do you have pH test kit? What is the pH of 
     your tap water? If it is 7.5 or higher, I think you don't need to worry 
     about Mg or Ca.
     If you use peat and soil, and keep fish in your tank, you will probably get 
     enough nitrates from that alone. Peat does not seem to liberate very much 
     nitrates (at least what I have) and decays very slowly.
     Potassium (K) is the element most like to be in short supply even from fish 
     food and soil and water. 1/8 tsp of potassium sulphate for each 10 gals of 
     water you drain out and replace will provide a steady supply. This works 
     out to around 10 ppm if I've done my math correctly and weighed the stuff 
     As for testing the clay, the best indicator is your eye. If it's red, it 
     has iron. Testing clay with water with your normal test kit won't work 
     because iron is not water soluble.
     I think you should use the Australian peat (you only need a couple of 
     pounds) because the stuff from the forest doesn't sound like real peat to 
     me. It would reduce hardness certainly; anything organic will do that but 
     what you need is something which is acidic and has had most of the soluble 
     nutrients leached out of it. Otherwise, as it decays in the substrate, it 
     produces too much nutrients and you get blue-green slime, green water or a 
     filamentous algae explosion. The only way to tell if your peat is releasing 
     nitrates is probably to measure with a test kit. Maybe somebody else knows 
     another test?
     Can you get a small container of bleach? You mix this 1 part with 19 parts 
     of water and use it to disinfect all plants which you put into your 
     aquarium to be sure they won't have any filamentous algaes. This is 
     especially important if you collect any plants from the wild. You dip the 
     plants in the bleach mixture 1-3 minutes and then rinse well with running 
     water. 1 minute for sensitive plants. 3 minutes for tough, thick leaved 
     plants if you have the dreaded Oedinum (sp?) green thread algae (feels like 
     horse hair)
     What will you use for lighting for your tank? If you cannot afford the 
     electricity and the fluorescent tubes, a cheap alternative is window light. 
     You need an east or west facing window which gets sun for 2-3 hours each 
     day. This is very strong lighting but you can reduce it by adding curtains 
     or other shading.
     What aquatic plants have you found so far?
     What will you use for CO2?
     Steve in Vancouver