pH of various substrates (updated on 20th Dec 09)

I have been testing the pH of various substrates which I had. I place the various substrates inside tupperwares and fill the tupperwares with bottled distilled water.


The results after 1-2 weeks of test are as follow:

1. plain distilled water: pH 6.6
2. GEX (light green packaging): pH 6.6
3. Kanuma soil: pH 6.4 - 6.5
4. 'Kotobuki' brand Dr Soil substrate: pH 6.5 - 6.6
5. used 'ADA' brand Amazonia + Aficana (50%:50%): pH 6.2 - 6.3
6. 'Horti' brand peat moss: pH 4.0 - 4.5
7. 'Horti' brand soil: pH 4.5
8. Lapis sand with coral chips: pH 8.0
9. Sphagnum moss from Japan (don't bother using low grade ones): pH 5.0
10. Akadama soil: pH 6.6
11. Lapis sand: pH 7.8
12. 'Muji' brand substrate: pH 7.4
13. Ketapang Leaf: pH <4.0
14. 'Aquamedi' brand Black Peat Granules: pH 4.0 - 4.5
15. Ocean Free brand Super Pro-Peat Granules: pH 4.0 - 4.5
16. Garden soil 'burnt soil': pH 8.0
17. ADA Amazonia II: pH 6.2
18. Volcanic rock: pH 7.2
19. First Layer Pure Laterite: pH 6.8
20. used ADA Amazonia: pH 6.8
21. SUDO Medaka Pink Sand: pH => 8.0
22. SUDO Crystal Orange Sand: pH 7.4
23. SUDO Real Brown Sand: pH 7.8
24. SUDO Bottom Sand: pH 7.2
25. used ADA Amazonia mixed with lapis sand: pH 7.0
26. live sphagnam moss: pH 5.0 - 5.5
27. used ADA Africana: pH 6.2 - 6.4
28. coconut husk: pH 7.0
29. Magic Soil: pH 6.4
30. lawn sand: pH 7.0

To arrange the substrates (distilled water to be used with them) in terms of ascending pH rounded to the nearest 0.5:

1. pH 4.0: 'Horti' brand peat moss, dried ketapang leaves (will cause discolouration of water readily), 'Aquamedi' brand Black Peat Granules, Ocean Free brand Super Pro-Peat Granules
2. pH 4.5: 'Horti' brand soil
3. pH 5.0: Sphagnum moss from Japan (don't bother using low grade ones), live sphagnam moss
4. pH 5.5: no suggestion so far
5. pH 6.0: ADA Amazonia II
6. pH 6.5: GEX substrate (light green packaging), Kanuma soil, 'Kotobuki' brand Dr Soil substrate, Akadama soil, used ADA Africana, Magic Soil
7. pH 7.0: First Layer Pure Laterite, Volcanic rock, used ADA Amazonia, SUDO Bottom Sand, used ADA Amazonia mixed with lapis sand, coconut husk, lawn sand
8. pH 7.5: 'Muji' brand substrate, SUDO Crystal Orange Sand
9. pH 8.0: Lapis sand, Garden soil 'burnt soil', SUDO Medaka Pink Sand, SUDO Real Brown Sand

pH tests are conducted using Zoolek Aquatest pH x 2 (4.5 - 9.0 and 6.0 - 8.0). I will add on to the list when I conduct more tests on more substrates. Hopefully these information will be useful when selecting substrates to achieve a certain pH either for potting mix or for conditioning the water for cultivating cryptocorynes.
The below are the pH of the water at the various natural habitat of various species of cryptocoryne which I had the good fortune to visit:

1. C. affinis 'West Pahang' - 7.2
2. C. auriculata 'Sungai Modor' - 6.0 to 6.5
3. C. bullosa 'Pakan' - 6.5
4. C. bullosa 'Sungai Seblak' - 5.5
5. C. cordata 'West Kalimantan' - 5.5
6. C. cordata 'Rompin' - 5.0 to 5.5
7. C. ciliata 'Sungei Sedili Besar' - about 6.5 if I never remembered wrongly
8. C. elliptica 'Perak' - 5.0 to 5.5
9. C. ferruginea 'Balai Ringin - 4.5 or less
10. C. ferruginea 'Bau' - 6.8 to 7.0
11. C. fusca 'West Kalimantan' - 5.5
12. C. griffithii 'Bintan' - 6.8
13. C. griffithii 'Karimun' - 6.5
14. C. griffithii 'Upper Thomson' - 5.5
15. C. keei 'Jambusan' - 8.0 to 8.5
16. C. keei 'West Kalimantan' - 6.5
17. C. lingua 'Sibu' - 6.5 to 7.0
18. C. longicauda 'Betong' - 4.5 or less
19. C. longicauda 'Bintan' - 6.6
20. C. longicauda 'Lachau' - 4.5
21. C. longicauda 'Pantu' - 4.5 or less
22. C. minima ' Perak' - 5.0 to 5.5
23. C. nurii 'Mersing' - 5.5 to 6
24. C. nurii 'West Pahang' - 7.0
25. C. pallidinervia 'Sibu' - 4.5 or less
26. C. striolata 'Sungai Assan' - 5.0 to 5.5
27. C. schulzei 'Kota Tinggi' - 4.5
28. C. uenoi 'Sabal Kruin' - 6.5
29. C. xpurpurea 'Tasik Bera' - 5.0 to 5.5
30. C. cf. xpurpurea 'Mersing Barat' - 5.5
31. C. yujii 'Sungai Nibong' - 4.5
32. C. sp. 'Kota Tinggi' - 6.5
33. C. sp. 'Lingga Island, Daik Timur' 'White Line' - 6.4
34. C. sp. 'Lingga Island, Reddish / Yellowish Flower' - 5.0 to 5.5
35. C. sp. 'Pahang River' - 5.5
36. C. sp. 'Peninsula Malaysia' - 5.0

Disclaimer: The accuracy of the above tests are subjected to the accuracy of the test kit used, which I have not verified via any form of calibration. There is no conclusion of the final pH that could be achieved for each substrate as I tested the pH at the 2nd week only. The amount of test substrate and distilled water used is not consistently measured. As distilled water is used, it would not be representative of the pH that could be achieved if you use say tap water instead which has more pH buffering capability?
Updated on: 20th Dec 2009